Patent Application
20100308664
1. Field of the Invention
The present invention relates to light fixture having a transformed low voltage receptacle used for powering among other things an electronically coded switching system. More particularly, the present invention relates to a self-powered device that generates one or more activation signals for a low voltage switch. Electrical power in a wireless transmitter is generated by deforming a piezoelectric element while pressing the face plate or individual membrane switches on the face plate. When the face plate is depressed, the electrical power may then be used to power a RF transmitter to send one or more electronic codes to actuate a device or to perform some other command function. The system comprises one or more transmitters, receivers and repeaters that communicate specific electronic codes to each other to increase system range and reliability. The receiver is powered by a DC voltage under 60 VDC. This low voltage is acquired from a step-down transformer that transforms the switched AC voltage (or high DC voltage) to 12-24VDC. The low voltage receiver generates a low voltage DC switching signal that activates a relay to switch the high voltage switched power. The relay may have bifurcated outputs to allow switching of two or more electrical fixtures or sets of fixtures. The receiver may also operate in conjunction with one or more high or low voltage repeaters/transceivers as well as other devices such as security and motion sensors, fire alarms and emergency power activation and testing systems.
2. Description of the Prior Art
Switches and latching relays for energizing lights, appliances and the like are well known in the prior art. Typical light switches comprise, for example, single-pole switches and three-way switches. A single-pole switch has two terminals that are hot leads for an incoming line (power source) and an outgoing line to the light. Three-way switches can control one light from two different places. Each three-way switch has three terminals: the common terminal and two traveler terminals. A typical pair of three-way switches uses two boxes each having two cables with the first box having an incoming line from a power source and an outbound line to the second box, and the second box having the incoming line from the first box and an outbound line to the light.
In each of these switching schemes it is often necessary to drill holes and mount switches and junction boxes for the outlets as well as to run cable. Drilling holes and mounting switches and junction boxes can be difficult and time consuming. Also, running electrical cable requires starting at a fixture, pulling cable through holes in the framing to each fixture in the circuit, and continuing all the way back to the service panel. Though simple in theory, getting cable to cooperate can be difficult and time consuming. Cable often kinks, tangles or binds while pulling, and needs to be straightened out somewhere along the run.
Remotely actuated switches/relays are also known in the art. Known remote actuation controllers include tabletop controllers, wireless remotes, timers, motion detectors, voice activated controllers, and computers and related software. For example, remote actuation means may include receiver modules that are plugged into a wall outlet and into which a power cord for a device may be plugged. The device can then be turned on and off by a remote controller/transmitter. Other remote actuation means include screw-in lamp receiver modules wherein the receiver module is screwed into a light socket, and then a bulb screwed into the receiver module. The light can be turned on and off and can be dimmed or brightened by a remote controller/transmitter.
Another example of one type of remote controller for the above described modules is a radio frequency (RF) base transceiver. With these controllers, a transceiver base is plugged into an outlet and can control groups of receiver modules in conjunction with a hand held wireless RF remote. RF repeaters may be used to boost the range of compatible wireless remote transmitters, switches and security system sensors by up to 150 ft. per repeater. The transceiver base is required for these wireless RF remote control systems and allows control of several lamps or appliances. Batteries are also required in the hand held wireless remote control systems.
Rather than using a hand held RF remote transmitter, remote wall transmitters may be used. These wall transmitters, which are up to ¾″ thick, are affixed to a desired location with an adhesive or fastener. In conjunction with a transceiver base unit (plugged into a 110V receptacle) the remote wall transmitter may control compatible receiver/transceiver modules and their associated switches. The wireless transmitters send an RF signal to the transceiver base unit and the transceiver base unit then transmits a signal along the existing 110V wiring in the home to compatible switches or receiver modules. Each switch can be programmed with an addressable signal. These wireless transmitters also require batteries.
These remotes control devices may also control, for example, audio/video devices such as the TV, VCR, and stereo system, as well as lights and other devices using an RF to infrared (IR) base. The RF remote can control audio/video devices by sending proprietary RF commands to a converter that translates the commands to IR. IR commands are then sent to the audio/video equipment. The infrared (IR) base responds to infrared signals from the infrared remotes and then transmits equivalent commands to compatible receivers.
A problem with conventional wall switches is that extensive wiring must be run both from the switch boxes to the lights and from the switch boxes to the power source in the service panels.
Another problem with conventional wall switches is that additional wiring must be run for lights controlled by more than one switch.
Another problem with conventional wall switches is that the voltage lines are present as an input to and an output from the switch.
Another problem with conventional wall switches is the cost associated with initial installation of wire to, from and between switches.
Another problem with conventional wall switches is the cost and inconvenience associated with remodeling, relocating or rewiring existing switches.
A problem with conventional RF transmitters is that they require an external power source such as high voltage AC power or batteries.
Another problem with conventional battery-powered RF transmitters is the cost and inconvenience associated with replacement of batteries.
Another problem with conventional AC-powered RF transmitters is the difficulty when remodeling in rewiring or relocating a wall transmitter.
Another problem with conventional RF switching systems is that a pair comprising a transmitter and receiver must generally be purchased together.
Another problem with conventional RF switching systems is that transmitters may inadvertently activate incorrect receivers.
Another problem with conventional RF switching systems is that receivers may accept an activation signal from only one transmitter.
Another problem with conventional RF switching systems is that transmitters may activate only one receiver.
Another problem with conventional RF switching systems is that multiple signals from transmitters and/or repeaters may inadvertently activate or deactivate a receiver switching mechanism.
Another problem with conventional RF switching systems is that receivers may have their reception blocked by building obstacles.
Another problem with conventional RF switching systems is that multiple types of receivers are necessary depending on the type of input voltage that is available.
Another problem with conventional RF switching systems is that receivers are not isolated from the voltage passed through the relay they control.
Accordingly, it would be desirable to provide a network of transmitters, receivers, repeaters, switch initiators, and/or latching relay devices that overcomes the aforementioned problems of the prior art.
The present invention provides a self-powered electronically coded switching system or device using an electroactive transducer. The piezoelectric element in the electroactive transducer is capable of deforming with a high amount of axial displacement, and when deformed by a mechanical impulse generates an electric field. The electroactive transducer is used as an electromechanical generator for generating an electrical signal that actuates a switch, actuator relay and/or locking mechanism. The electroactive transducer is used as an electromechanical converter/generator for generating an electrical signal that, with the accompanying circuitry, generates an RF signal that initiates a latching or relay mechanism. The latching or relay mechanism thereby turns electrical devices such as lights and appliances on and off or provides an intermediate or dimming signal, or initiates other functions.
A receiver controls the relay or other switching device. Preferably the receiver is located within/on a lighting fixture adapted to receive and retain the receiver. The fixture has a step down transformer therein for transforming the line voltage, e.g., 120 or 277 VAC to a low DC voltage, e.g., 12-24 VDC for powering the receiver and/or other devices. The receiver is programmable to perform many different command functions for controlling a variety of electrical devices such as lights, sensors, fan motors, emergency lighting or the like. The receiver, therefore, may have multiple connection points, in order to provide the correct logic output to the controlled devices. Alternately, the lighting fixture may have multiple low voltage connection points for control of those devices either through an already established wiring system, or for wireless control through the receiver. The fixture may also have a battery therein for providing emergency power to lighting, sensors, alarms and the like. The emergency power/battery testing is controllable wirelessly by the receiver.
Co-owned U.S. Pat. No. 6,630,894 entitled “Self-Powered Switching Device,” which is hereby incorporated by reference, discloses a self-powered switch where the electroactive element generates an electrical pulse. Co-owned U.S. Pat. No. 6,812,594 entitled “Self-Powered Trainable Switching Network,” which is hereby incorporated by reference, discloses a network of switches such as that disclosed in U.S. Pat. No. 6,630,894, with the modification that the switches and receivers are capable accepting a multiplicity of coded RF signals. Co-owned U.S. Pat. No. 7,084,529 entitled “Self-Powered Switch Initiation System,” which is hereby incorporated by reference, discloses a network of switches such as that disclosed in U.S. Pat. Nos. 6,630,894 and 6,812,594, with additional modifications to the coded RF signals, multiple training topologies, and an improved mounting and actuation means, as well as circuitry to support the output electrical signal of the transducer. Co-owned U.S. Pat. No. 7,126,497 entitled “Self-Powered Switch Initiation System,” which is hereby incorporated by reference, discloses a network of switches such as that disclosed in U.S. Pat. Nos. 6,630,894 and 6,812,594, with additional modifications to the actuation mechanism, and further incorporating rechargeable batteries for the receiver, transmitter and/or transceivers. Co-owned U.S. Pat. No. 7,161,276 entitled “Self-Powered, Electronic Keyed Multifunction Switching System,” which is hereby incorporated by reference, discloses a network of switches such as that disclosed in U.S. Pat. Nos. 6,630,894 and 6,812,594, with additional modifications that the transmitters incorporate membrane switches for multiple function codes.
The mechanical actuating means for the electroactive generator element applies a suitable mechanical impulse to the electroactive generator element in order to generate an electrical signal, such as a pulse, multiple pulses and/or waves having sufficient magnitude and duration to power and actuate downstream circuit components. A mechanism similar to a light switch or pressure switch, for example, may apply pressure through a toggle, snap action, paddle, plunger, plucking and/or ratchet mechanism. Larger or multiple electroactive generator elements may also be used to generate the electrical signal.
In the present invention a self-powered switch initiation system uses an electroactive element to develop an oscillating electrical signal. The accompanying circuitry is designed to work with that signal and generate a coded RF transmission. The codes are preferably a 32-bit binary code comprising a unique (i.e., one of 224 to 230 combinations) transmitter identification code and a function code. To further enhance the system, the system uses a repeater/transceiver system to increase transmission range and reliability of receipt of transmitted signals. The codes sent by the transmitter are modified and rebroadcast by the repeater(s). The response action by the receiver and repeaters to codes either from a transmitter or another repeater depends on the nature of the received code. The nature of the information contained in the code e.g., identification, function and source, is further described. Repeaters also use a poling/initialization routine to assign times slots to each repeater to prevent interference between repeaters.
In one embodiment of the invention, the electroactive generator output signal powers an RF transmitter which sends an RF signal to an RF receiver which then actuates the relay. In yet another embodiment, the electromagnetic or electroactive generator output signal powers a transmitter, which sends a pulsed (coded) RF signal to an RF receiver which then actuates the relay. Digitized RF signals are coded (as with a garage door opener) to only activate the relay that is trained to receive that digitized coded RF signal. The transmitters may be capable of developing one or more coded RF signals and the receivers likewise are capable of receiving one or more coded RF signals. Furthermore, the receivers may be “trainable” to accept coded RF signals from new or multiple transmitters and repeaters. In another embodiment of the invention, rechargeable batteries are used to capture some of the electrical output of the generator and apply the stored energy to circuit components. In another embodiment of the invention uses a transceiver/repeater and transmission circuit to receive and retransmit RF signals within the system.
In the preferred embodiment, the receiver is powered by a low DC voltage, e.g., 12-24 VDC, and sends a low voltage actuation signal to a relay controller. The low voltage is obtained via a power pack and/or transformer that steps down the switched voltage, e.g., 120 or 277 VAC, to the low voltage. This transformer is preferably located in the light fixture, and provides low voltage outputs to one or more devices, including outputs for a low voltage receiver, a sensor, a light, an alarm, emergency lighting or the like. The receiver generates a low voltage actuation signal activates the relay that switches the high switched voltage. The receiver may also generate a low voltage activation signal for actuating or testing the low voltage sensor, a light, an alarm, emergency lighting or the like. The low voltage transformer may also supply a battery for emergency power to alarms, sensors, emergency lighting and other health and safety devices. Testing or operation of these health and safety devices can be activated from the receiver.
Preferably the receiver has an output of at least three activation signals corresponding to “ALL OFF”, “ALL ON”, and “HALF ON” which signals are directed through one or more relay controllers to the bifurcated/three-way output(s) of the switched relay. Alternately, the receiver may have multiple output ports, which are selectable dependent upon the device to be controlled. The receiver is programmable to control multiple devices, i.e., the receiver is programmed to control many different devices, and the programming varies dependent upon the operating mode of the device to be controlled. Each of the output ports of the receiver has access to different programs/operating modes within the receiver. Therefor, attaching a device to defined output ports allows those devices to be controlled with the appropriate programming/control modes from a single receiver.
Accordingly, it is a primary object of the present invention to provide a switching system in which an electroactive or piezoelectric element is used to power an RF transmitter for activating an electrical device.
It is another object of the present invention to provide a device of the character described in which transmitters may be installed without necessitating additional wiring.
It is another object of the present invention to provide a device of the character described in which transmitters may be installed without cutting holes into the building structure.
It is another object of the present invention to provide a device of the character described in which transmitters do not require external electrical input such as 120 or 220VAC or batteries.
It is another object of the present invention to provide a device of the character described incorporating an electroactive converter that generates an electrical signal of sufficient duration and magnitude to power a radio frequency transmitter for activating a latching relay and/or switch initiator.
It is another object of the present invention to provide a device of the character described incorporating a transmitter that is capable of developing at least one coded RF signal.
It is another object of the present invention to provide a device of the character described incorporating a receiver capable of receiving at least one coded RF signal from at least one transmitter.
It is another object of the present invention to provide a device of the character described incorporating a receiver capable of “learning” to accept coded RF signals from one or more transmitters.
It is another object of the present invention to provide a device of the character described for use in actuating multiple command functions for electrical devices and other fixtures in a building.
It is another object of the present invention to provide a device of the character described which uses a repeater system for extending the range of transmission and reception reliability between transmitters and receivers.
It is another object of the present invention to provide a device of the character described in which a power pack is used to provide low voltage DC power to a receiver.
It is another object of the present invention to provide a device of the character described in which a low voltage output transformer built into a light fixture is used to provide low voltage DC power to multiple devices, including a receiver, repeater, sensor, alarm, battery or emergency lighting.
It is another object of the present invention to provide a device of the character described in which a low voltage DC receiver is used to provide a low voltage DC signal to a relay controller within a power pack.
It is another object of the present invention to provide a device of the character described in which low voltage DC receiver is used to provide one or more low voltage DC signals to one or more relay controllers for providing two or more switching options.
It is another object of the present invention to provide a device of the character described in which low voltage DC receiver is used to provide one or more low voltage DC signals to one or more relay controllers for providing two or more switching options.
It is another object of the present invention to provide a device of the character described in which a low voltage DC powered receiver has multiple outputs for control of multiple DC powered devices including a sensor, alarm, lighting, battery or emergency lighting.
It is another object of the present invention to provide a device of the character described in which a lighting fixture includes a low voltage transformer as well as retention means for a low voltage receiver.
Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description thereof.
a is an elevation view showing the details of construction of the flextensional piezoelectric generator of
a is an elevation view showing the details of construction of the flextensional piezoelectric generator of
a-7c show an alternate clamping mechanism for retention of an end of a flextensional piezoelectric transducer in undeflected and deflected states;
a-a-c show the electrical signal generated by the transducer, the electrical output signal of the rectifier at the junction with the capacitor and the regulated electrical signal respectively;
a and 11b are elevation views of the preferred deflector assembly of the present invention showing the transducer in the undeflected and deflected positions respectively;
c is a plan view of the preferred deflector assembly of the present invention showing the transducer in the undeflected position;
a-a-e are elevation views of one embodiment of a plucker paddle mechanism as in
Piezoelectric and electrostrictive materials (generally called “electroactive” devices herein) develop an electric field when placed under stress or strain. The electric field developed by a piezoelectric or electrostrictive material is a function of the applied force and displacement causing the mechanical stress or strain. Conversely, electroactive devices undergo dimensional changes in an applied electric field. The dimensional change (i.e., expansion or contraction) of an electroactive element is a function of the applied electric field. Electroactive devices are commonly used as drivers, or “actuators” due to their propensity to deform under such electric fields. These electroactive devices when used as transducers or generators also have varying capacities to generate an electric field in response to a deformation caused by an applied force. In such cases they behave as electrical generators.
Electroactive devices include direct and indirect mode actuators, which typically make use of a change in the dimensions of the material to achieve a displacement, but in the present invention are preferably used as electromechanical generators. Direct mode actuators typically include a piezoelectric or electrostrictive ceramic plate (or stack of plates) sandwiched between a pair of electrodes formed on its major surfaces. The devices generally have a sufficiently large piezoelectric and/or electrostrictive coefficient to produce the desired strain in the ceramic plate. However, direct mode actuators suffer from the disadvantage of only being able to achieve a very small displacement (strain), which is, at best, only a few tenths of a percent. Conversely, direct mode generator-actuators require application of a high amount of force to piezoelectrically generate a pulsed momentary electrical signal of sufficient magnitude to activate a latching relay.
Indirect mode actuators are known to exhibit greater displacement and strain than is achievable with direct mode actuators by achieving strain amplification via external structures. An example of an indirect mode actuator is a flextensional transducer.
Flextensional transducers are composite structures composed of a piezoelectric ceramic element and a metallic shell, stressed plastic, fiberglass, or similar structures. The actuator movement of conventional flextensional devices commonly occurs as a result of expansion in the piezoelectric material which mechanically couples to an amplified contraction of the device in the transverse direction. In operation, they can exhibit several orders of magnitude greater strain and displacement than can be produced by direct mode actuators.
The magnitude of achievable deflection (transverse bending) of indirect mode actuators can be increased by constructing them either as “unimorph” or “bimorph” flextensional actuators. A typical unimorph is a concave structure composed of a single piezoelectric element externally bonded to a flexible metal foil, and which results in axial buckling (deflection normal to the plane of the electroactive element) when electrically energized. Common unimorphs can exhibit transverse bending as high as 10%, i.e., a deflection normal to the plane of the element equal to 10% of the length of the actuator. A conventional bimorph device includes an intermediate flexible metal foil sandwiched between two piezoelectric elements. Electrodes are bonded to each of the major surfaces of the ceramic elements and the metal foil is bonded to the inner two electrodes. Bimorphs exhibit more displacement than comparable unimorphs because under the applied voltage, one ceramic element will contract while the other expands. Bimorphs can exhibit transverse bending of up to 20% of the Bimorph length.
For certain applications, asymmetrically stress biased electroactive devices have been proposed in order to increase the transverse bending of the electroactive generator, and therefore increase the electrical output in the electroactive material. In such devices, (which include, for example, “Rainbow” actuators (as disclosed in U.S. Pat. No. 5,471,721), and other flextensional actuators) the asymmetric stress biasing produces a curved structure, typically having two major surfaces, one of which is concave and the other which is convex.
Thus, various constructions of flextensional piezoelectric and ferroelectric generators may be used including: indirect mode actuators (such as “moonies” and, CYMBAL); bending actuators (such as unimorph, bimorph, multimorph or monomorph devices); prestressed actuators (such as “THUNDER” and rainbow” actuators as disclosed in U.S. Pat. No. 5,471,721); and multilayer actuators such as stacked actuators; and polymer piezofilms such as PVDF. Many other electromechanical devices exist and are contemplated to function similarly to power a transceiver circuit in the invention.
Referring to
The THUNDER element 12 is as a composite structure, the construction of which is illustrated in
During the cooling step of the process (i.e. after the adhesive layers 66 and 66a have re-solidified) the ceramic layer 67 becomes compressively stressed by the adhesive layers 66 and 66a and pre-stress layer 64 due to the higher coefficient of thermal contraction of the materials of the adhesive layers 66 and 66a and the pre-stress layer 64 than for the material of the ceramic layer 67. Also, due to the greater thermal contraction of the laminate materials (e.g. the first pre-stress layer 64 and the first adhesive layer 66) on one side of the ceramic layer 67 relative to the thermal contraction of the laminate material(s) (e.g. the second adhesive layer 66a) on the other side of the ceramic layer 67, the ceramic layer deforms in an arcuate shape having a normally convex face 12a and a normally concave face 12c, as illustrated in
Referring to
Alternately, the second prestress layer 68 may comprise the same material as is used in the first prestress layer 64, or a material with substantially the same mechanical strain characteristics. Using two prestress layers 64, 68 having similar mechanical strain characteristics ensures that, upon cooling, the thermal contraction of the laminate materials (e.g. the first pre-stress layer 64 and the first adhesive layer 66,) on one side of the ceramic layer 67 is substantially equal to the thermal contraction of the laminate materials (e.g. the second adhesive layer 66a and the second prestress layer 68) on the other side of the ceramic layer 67, and the ceramic layer 67 and the transducer 12 remain substantially flat, but still under a compressive stress.
Alternatively, the substrate comprising a separate prestress layer 64 may be eliminated and the adhesive layers 66 and 66a alone or in conjunction may apply the prestress to the ceramic layer 67. Alternatively, only the prestress layer(s) 64 and 68 and the adhesive layer(s) 66 and 66a may be heated and bonded to a ceramic layer 67, while the ceramic layer 67 is at a lower temperature, in order to induce greater compressive stress into the ceramic layer 67 when cooling the transducer 12.
Referring now to
Referring now to
Referring again to
A flexible insulator may be used to coat the convex face 12a of the transducer 12.
This insulative coating helps prevent unintentional discharge of the piezoelectric element through inadvertent contact with another conductor, liquid or human contact. The coating also makes the ceramic element more durable and resistant to cracking or damage from impact. Since LaRC-SI is a dielectric, the adhesive layer 67a on the convex face 12a of the transducer 12 may act as the insulative layer. Alternately, the insulative layer may comprise a plastic, TEFLON or other durable coating.
Electrical energy may be recovered from or introduced to the generator element 12 (or 12D) by a pair of electrical wires 14. Each electrical wire 14 is attached at one end to opposite sides of the generator element 12. The wires 14 may be connected directly to the electroplated 65 and 65a faces of the ceramic layer 67, or they may alternatively be connected to the pre-stress layer(s) 64 and or 68. The wires 14 are connected using, for example, conductive adhesive, or solder 20, but most preferably a conductive tape, such as a copper foil tape adhesively placed on the faces of the electroactive generator element, thus avoiding the soldering or gluing of the conductor. As discussed above, the pre-stress layer 64 is preferably adhered to the ceramic layer 67 by LaRC-SI material, which is a dielectric. When the wires 14 are connected to the pre-stress layer(s) 64 and/or 68, it is desirable to roughen a face of the pre-stress layer 68, so that the pre-stress layer 68 intermittently penetrates the respective adhesive layers 66 and 66a, and makes electrical contact with the respective electroplated 65 and 65a faces of the ceramic layer 67. Alternatively, the Lam-SI adhesive layer 66 may have a conductive material, such as Nickel or aluminum particles, used as a filler in the adhesive and to maintain electrical contact between the prestress layer and the electroplated faces of the ceramic layer(s). The opposite end of each electrical wire 14 is preferably connected to an electric pulse modification circuit 10.
Prestressed flextensional transducers 12 are desirable due to their durability and their relatively large displacement, and concomitant relatively high voltage that such transducers are capable of developing when deflected by an external force. The present invention however may be practiced with any electroactive element having the properties and characteristics herein described, i.e., the ability to generate a voltage in response to a deformation of the device. For example, the invention may be practiced using magnetostrictive or ferroelectric devices. The transducers also need not be normally arcuate, but may also include transducers that are normally flat, and may further include stacked piezoelectric elements.
Although in the preferred embodiment of the invention, the electro-mechanical generator comprises a THUNDER actuator 12 or other electroactive element, it is within the scope of the invention to include other types of electromechanical generators. For example. The electromechanical generator may comprise a series of coils and one or more magnets. When the buttons of the keypad are pressed the coils and magnets have motion relative to each other, and this induces a current in the coils.
In operation, when a force is applied to a face 12a or 12c of the actuator 12, the force deforms the piezoelectric element 67. The force may be applied to the piezoelectric actuator 12 by any appropriate means such as by application of manual pressure directly to the piezoelectric actuator 12, or by other mechanical means. The force may also be applied to an edge of the actuator 12. More specifically, the actuator 12 has first and second ends 121, 122. One of the ends 121 is preferably in a fixed, i.e., non-moveable position via appropriate fixation means such as clamps and/or screws. The opposite end, or free end 122 may be deflected by appropriate deflection means. The mechanical impulse (or removal thereof) is of sufficient force to cause the actuator 12 to deform quickly and accelerate over a distance (approximately 1-5 mm) which generates an electrical signal of sufficient magnitude to activate an electronic circuit. In the embodiments of the invention in
A description of the various means of applying a releasing a force to deflect the edge 122 of the actuator 12 (both flat and arcuate), thereby producing the desired electrical signal is included in: commonly owned U.S. Pat. No. 6,630,894 entitled “Self-Powered Switching Device”; co-owned U.S. Pat. No. 6,812,594 entitled “Self-Powered Trainable Switching Network”; co-owned U.S. Pat. No. 7,084,529 entitled “Self-Powered Switch Initiation System”; co-owned U.S. Pat. No. 7,126,497 entitled “Self-Powered Switch Initiation System”; and co-owned U.S. Pat. No. 7,161,276 entitled “Self-Powered, Electronic Keyed Multifunction Switching System,” all of which are hereby incorporated by reference.
As previously mentioned, the applied force causes the piezoelectric transducer 12 to deform. By virtue of the piezoelectric effect, the deformation of the piezoelectric element 67 generates an instantaneous voltage between the faces 12a and 12c of the transducer 12, which produces a pulse of electrical energy. Furthermore, when the force is removed from the piezoelectric transducer 12, the transducer 12 recovers its original arcuate shape. This is because the bending of the substrate (and attached layers) stores mechanical (spring) energy which is released upon removal of the force. Additionally, the substrate or prestress layers 64 and 68 to which the ceramic 67 is bonded exert a compressive force on the ceramic 67, and the transducer 12 thus has an additional restoring force that causes the transducer 12 to return to its undeformed neutral state. On the recovery stroke of the transducer 12, the ceramic 67 returns to its undeformed state and thereby produces another electrical pulse of opposite polarity. The downward (applied) or upward (recovery) strokes cause a force over a distance that is of sufficient magnitude to create the desired electrical pulse. The duration of the recovery stroke, and therefore the duration of the pulse produced, is preferably in the range of 50-100 milliseconds, depending on the mechanical properties of the transducer, including its natural frequency of vibration.
Referring to FIG. 4.: In the preferred embodiment of the invention, the transducer 12 is clamped at one end 121 and the mechanical impulse is applied to the edge on the free end 122, i.e., at the end opposite to the clamped end 121 of the transducer 12. By applying the force to the edge on the free end 122 of the transducer 12 and releasing it, the actuator oscillates between the release position, to another position past the undeformed position, and then dampedly oscillates between the deformed positions returning to the undeformed position, by virtue of the substrates (spring steel) restoring force. Therefore, the electrical pulse that is generated upon removal of the force is an oscillating wave (rather than a single pulse as with the prior actuating means disclosed above).
Referring again to
One end 121 of a transducer 12 is placed between the mating surfaces 70a and 75a of the base and clamping plates 70 and 75. The mating surfaces 70a and 75a are then urged towards each other with the screw 76 to rigidly hold the end 121 of the transducer 12 in place between the base and clamping plates 70 and 75 with the opposite end 122 of the transducer 12 free to be moved by a mechanical impulse applied manually or preferably by a deflector assembly 72. The transducer 12 may further be aligned and securely retained between the base plate 70 and clamping plate 75 by means of one or more pins (not shown) on the base plate 70 and/or clamping plate 75 and holes (not shown) in the end 121 of the transducer 12.
Referring now to
The clamping assembly 75 holds the transducer 12 in place in its relaxed, i.e., undeformed state above the base plate 70 with the free end 122 of the transducer 12 in close proximity to a deflector 72 assembly. More specifically, the transducer 12 is preferably clamped between the mating surfaces 70a and 75a of the base and clamping plates 70 and 75 with the convex face 12a of the transducer 12 facing the base plate 70. Since the transducer 12 in its relaxed state is arcuate, the convex face 12a of the transducer 12 curves away from the upper surface 70a of the base plate 70 while approaching the free end 122 of the transducer 12. Mechanical force may then be applied to the free end 122 of the transducer 12 in order to deform the electroactive element 67 to develop an electrical signal.
Because of the composite, multi-layer construction of the transducer 12 it is important to ensure that the clamping member 75 not only holds the transducer 12 rigidly in place, but also that the transducer 12 is not damaged by the clamping member 75. In other words, the transducer 12, and more specifically the ceramic layer 67, should not be damaged by the clamping action of the clamping member 75 in a static mode, but especially in the dynamic state when applying a mechanical impulse to the transducer 12 with the plunger 72. For example, referring to
Referring again to
As can be seen in
The recess 80 is designed not only to prevent damage to the ceramic layer 67, but also to provide a surface along which electrical contact can be maintained with the electrode 68 on the convex face of the transducer 12. The recess 80 extends into the base plate 70 and has a variable depth, preferably being angled to accommodate the angle at which the convex face 12a of the transducer 12 rises from the recess 80 and above the top surface 70a of the base plate 70. More specifically, the recess 80 preferably has a deep end 81 and a shallow end 82 with its maximum depth at the deep end 81 beneath the clamping member 75 and substrate 12 just before where the ceramic layer 67 extends into the recess 80 at point C. The recess 80 then becomes shallower in the direction approaching the free end 122 of the transducer 12 until it reaches its minimum depth at the shallow end 82.
The recess 80 preferably contains a layer of compliant material 85 (preferably rubber, but alternately cork, urethane, silicone, felt or the like) along its lower surface which helps prevent the ceramic layer 67 from being damaged when the transducer 12 is deformed and the lower edge C of the ceramic layer 67 is pushed into the recess 80. Preferably the compliant layer 85 is of substantially uniform thickness along its length, the thickness of the compliant layer 85 being substantially equal to the depth of the recess 80 at the shallow end 82. The length of the compliant layer 85 is preferably slightly shorter than the length of the recess 80 to accommodate the deformation of the compliant layer 85 when the transducer 12 is pushed into the recess and compliant layer 85.
The compliant layer 85 preferably has a flexible electrode layer 90 overlying it to facilitate electrical contact with the aluminum layer 68 on the ceramic layer 67 on the convex face 12a of the transducer 12. More preferably, the electrode layer 90 comprises a layer of copper overlaying a layer of KAPTON film, as manufactured by E.I. du Pont de Nemours and Company, bonded to the compliant layer 85 with a layer of adhesive, preferably CIBA adhesive. The electrode layer 90 preferably extends completely across the compliant layer 85 from the deep end 81 to the shallow end 82 of the recess 80 and may continue as far as desired beyond the recess 80 along the top surface 70a of the base plate 70.
In the preferred embodiment of the invention, the end 121 of the transducer 12 is not only secured between the clamping plate 75 and the base plate 70, but the second prestress layer 68 covering the ceramic layer 67 of the transducer 12 is in constant contact with the electrode layer 90 in the recess 80 at all times, regardless of the position of the transducer 12 in its complete range of motion. To this end, the depth of the recess 80 (from the top surface 70a to the electrode 90) is at least equal to a preferably slightly less than the thickness of the laminate layers (adhesive layers 66, ceramic layer 67 and prestress layer 68) extending into the recess 80. The electrode layer is preferably adhered to either or both the aluminum layer 68 and the compliant layer 85, with a suitable adhesive, including for example, conductive adhesives.
An assembly was built having the following illustrative dimensions. The transducer 12 comprised a 1.59 by 1.79 inch spring steel substrate that was 8 mils thick. A 1-1.5 mil thick layer of adhesive having a nickel dust filler in a 1.51 inch square was placed one end of the substrate 0.02 inch from three sides of the substrate (leaving a 0.25 inch tab on one end 121 of the transducer 12). An 8-mil thick layer of PZT-5A type piezoelectric material in a 1.5 inch square was centered on the adhesive layer. A 1-mil thick layer of adhesive (with no metal filler) was placed in a 1.47 inch square centered on the PZT layer. Finally, a 1-mil thick layer of aluminum in a 1.46 inch square was centered on the adhesive layer. The tab 121 of the transducer 12 was placed in a recess in a clamping block 76 having a length of 0.375 inch and a depth of 4 mils. The base plate 70 had a 0.26 in long recess 80 where the deep end 81 of the recess had a depth of 20 mils and tapered evenly to a depth of 15 mils at the shallow end 82 of the recess 80. A rubber compliant layer 85 having a thickness of 15 mils and a length of 0.24 inches was placed in the recess 80. An electrode layer of 1 mil copper foil overlying 1 mil KAPTON tape was adhered to the rubber layer and extended beyond the recess 1.115 inches. The clamping member 75 was secured to the base plate 70 with a screw 76 and the aluminum second prestress layer of the transducer 12 contacted the electrode 90 in the recess 80 substantially tangentially (nearly parallel) to the angle the transducer 12 thereby maximizing the surface area of the electrical contact between the two.
As shown in
As shown in
Referring now to
As can be seen in
Electrical contact to each of the faces 12a, 12c of the transducer 12 may be provided by use of wires 14 soldered to each face 12a, 12c. Alternately, conductive foil may be adhered to each face 12a, 12c of the transducer 12. As yet another alternative, by using metallic projections 185-188 on the clamping plates 175, 177, electrical contact with each of the faces 12a, 12c of the transducer 12 may be maintained, and conductors 14 may be attached to one or both of the projections 185, 186 and 187, 188 on each side 12a, 12c of the transducer 12, or alternately to the projections 185, 186 and 187, 188 via each of the plates 175, 177. By making electrical connections to conductive projections 185-188, bending and point stresses are eliminated from the conductors 14 electrically connected to each face 12a, 12c of the transducer 12 as it is bent.
Referring to
Referring now to
Referring again to
Referring again to
Referring again to
Thus, when the crossbar 265 is depressed, the second ends 261b, 262b of the pivot arms 261, 262 move upwardly and contact the first ends 271a, 272a of the rocker arms 271, 272, causing the rocker arms 271, 272 to rotate about the rocker arm pins 274. This causes the second ends 271b, 272b of the rocker arms 271, 272 to be depressed. As the second ends 271b, 272b of the rocker arms 271, 272 are depressed, they contact the rollers 305 with a downward force, and the plucker assembly 300 is guided by the slide pins 304 and slide grooves 308 to cause the plucker paddle 301 to move simultaneously downward and away from the free end of 122 the transducer 12. The minimum or lowest position of the plucker assembly is beyond the free end 122 of the transducer 12, and therefore, as the plucker paddle 301 moves downward and outward, the free end 122 of the transducer 12 is released by the plucker paddle 301. Thus as the plucker assembly is depressed, the free end 122 of the transducer 12 is depressed from its neutral position 291 to a deflected position 292 at which position the paddle 301 releases the free end 122 of the transducer 12. The free end 122 of the transducer 12 then oscillates between positions 291 and 292.
Referring now to
The transducer 12 is typically is curved along its length, i.e., the longitudinal dimension and this curvature allows the element 12 to be bent or “plucked” substantially before it reaches a flattened state. The transducer 12 is also curved across its transverse dimension, i.e., the transverse dimension normal to the thickness and longitudinal dimensions. To ensure a quick “release”, the shape of the edge 301a of the plucking paddle 300 should generally match this transverse curve. The radius curvature of the transducer 12 in the transverse plane is approximately 6 inches, and therefore the same radius should be used for the curve edge 301a in the transverse plane of the paddle 301. Different sized transducers 12 will have higher or lower transverse radii of curvature, so regardless of the size of the transducer 12, the radius of curvature for the curved edge 301a in the transverse plane of the paddle 301 should substantially match the transverse curvature of the transducer 12.
Although both paddle 301 dimensions affect durability, and both dimensions affect performance, the tip radius has more of an effect on element 12 performance, while the transverse curve has a greater effect on the element's 12 substrate wear, and therefore is more of an influence on its life expectancy. This is because the transverse radius determines how much of the paddle 301 contacts the element 12. A greater contact area is equates with less wear and longer substrate life, i.e., durability. As stated above, by manufacturing the paddle 301 from sufficiently hard or hardened materials, the edge 301a of the paddle 301 can be made with very small radius. The tip 301a of the plucking paddle 301 may be coated with a very hard material with low friction, thereby lowering the plucking resistance. Hardened, low friction materials are useful in increasing the power output of a transducer 12 without increasing the required displacement or amount of bending, or allowing the generation of similar electrical energy output with lower “button force”, and increasing wear resistance.
Referring again to
Referring now to
Referring again to
A force applied to the deflector assembly 72 described above causes the piezoelectric transducer 12 to deform from position 291 to position 292 and by virtue of the piezoelectric effect, the deformation of the piezoelectric element 67 generates an instantaneous voltage between the faces 12a and 12c of the transducer 12, which produces an electrical signal. Furthermore, when the force is removed from the piezoelectric transducer 12, i.e., when released by the plucker assembly 300 at position 292, the transducer 12 oscillates between positions 291 and 292 until it gradually returns to its original shape. As the transducer 12 oscillates, the ceramic layer 67 strains, becoming alternately more compressed and less compressed. The polarity of the voltage produced by the ceramic layer 67 depends on the direction of the strain, and therefore, the polarity of the voltage generated in compression is opposite to the polarity of the voltage generated in tension. Therefore, as the transducer 12 oscillates, the voltage produced by the ceramic element 67 oscillates between a positive and negative voltage for a duration of time. The duration of the oscillation, and therefore the duration of the oscillating electrical signal produced, is preferably in the range of 100-250 milliseconds, depending on the shape, mounting and amount of force applied to the transducer 12. The wave form of the oscillating voltage is illustrated in
When the end 122 of the transducer 12 is deflected and then released (either manually or using a deflector assembly 72 such as in
The applied force, whether by manual or other mechanical deflection means 72 causes the piezoelectric transducer 12 to deform and by virtue of the piezoelectric effect, the deformation of the piezoelectric element 67 generates an instantaneous voltage between the faces 12a and 12c of the transducer 12, which produces an electrical signal. Furthermore, when the force is removed from the piezoelectric transducer 12, the transducer 12 oscillates between positions 291 and 292 until it gradually returns to its original shape. As the transducer 12 oscillates, the ceramic layer 67 strains, becoming alternately more compressed and less compressed. The polarity of the voltage produced by the ceramic layer 67 depends on the direction of the strain, and therefore, the polarity of the voltage generated in compression is opposite to the polarity of the voltage generated in tension. Therefore, as the transducer 12 oscillates, the voltage produced by the ceramic element 67 oscillates between a positive and negative voltage for a duration of time. The duration of the oscillation, and therefore the duration of the oscillating electrical signal produced, is preferably in the range of 100-500 milliseconds, depending on the shape, mounting and amount of force and number of plucks applied to the edge of the transducer 12.
The electrical signal generated by the transducer 12 is applied to downstream circuit elements via wires 14, and conductive foil, solder or conductive adhesive connected to the transducer 12. More specifically, a first wire 14 is connected to the electrode 90 which extends into the recess 80 and contacts the electrode 68 on the convex face 12a of the transducer 12 or to a foil adhered to the lower face 12a of the transducer 12. Preferably the wire 14 is attached to a conductive foil (not shown) adhered to the face 12a of the transducer 12 situated above the recess 80 and compliant layer 85. Alternately, the wire 14 is connected to the electrode 90 outside of the recess close to the end of the base plate 70 opposite the end having the clamping member 75. A second wire 14 is connected directly to the first prestress layer 64, i.e., the substrate 64 which acts as an electrode on the concave face 12c of the transducer 12.
Referring now to
Surrounding the button 210 and mounted to the base plate 70 is a frame 250 having four walls 251, 252, 253 and 254 which extend perpendicularly from the top surface 70a of the base plate 70. There are preferably one or more clips along one or more of the wall 251, 252, 253 and 254 edges that engage with the edge of the bottom face 70b of the base 70.
The frame walls 251, 252, 253 and 254 may also have a tapered or beveled portion 225 above the vertical portion of the walls (where the walls attach to and surround the underlying base 70) beveling inward towards the button 210 in the center of the frame 250. The frame 250 is removable from the base 70 and when removed allows access to other components, for example the hinge 216 pins to which the button 210 is attached, or to access screw holes 228 in the base 70, which may be used to attach the base 70 to a wall or other mounting surface.
In each embodiment of a self powered RF signal generator, the transducer 12, base 70 and associated transmission circuitry are enclosed in a case, such as described above having a base 200, a button 210 and a frame 250. The case may be made of a variety of materials including plastics and metal or combinations thereof. Most preferably, the case 200 comprises plastic. It has been discovered that the character of the RF signal radiated from the antenna 60 in the transmitter circuit 126 varies with the placement of the antenna 60 in relation to parts of the casing 200 as well as other obstructions placed in proximity to the antenna. To this end it is preferred that the antenna 60 be fixedly mounted to the base 70. Most preferably, the antenna 60 is affixed to the casing in a channel in the base 70/200. Furthermore, it is preferable that at least a portion of the base 70 be made of metal. Objects (i.e., in walls) to which the base 70 is mounted may cause interference with the signal radiated from the antenna 60. Therefore a portion of the base 70 is preferred to be metallic in order to shield the antenna from any interference. Most preferably, a metallic foil 400 is affixed to the back face 70b of the base 70 in proximity to the antenna 60 on the opposite face 70a of the base 70.
The pulse of electrical energy is transmitted from the transducer or generator 12 via the electrical wires 14 connected to each of the transducer 12 to a switch or relay 90. The pulse of electrical energy is of sufficient magnitude to cause the switch/relay 90 to toggle from one position to another. Alternatively and preferably, the electrical pulse is first transmitted through a pulse modification circuit 10 in order to modify the character, i.e, current, voltage, frequency and/or pulse width of the electrical signal.
Referring to
The transducer 12 is first connected to a rectifier 31. Preferably the rectifier 31 comprises a bridge rectifier 31 comprising four diodes D1, D2, D3 and D4 arranged to only allow positive voltages to pass. The first two diodes D1 and D2 are connected in series, i.e., the anode of D1 connected to the cathode of D2. The second two diodes D3 and D4 are connected in series, i.e., the anode of D3 connected to the cathode of D4. The anodes of diodes D2 and D4 are connected, and the cathodes of diodes D1 and D3 are connected, thereby forming a bridge rectifier. The rectifier is positively biased toward the D2-D4 junction and negatively biased toward the D1-D3 junction. One of the wires 14 of the transducer 12 is electrically connected between the junction of diodes D1 and D2, whereas the other wire 14 (connected to the opposite face of the transducer 12) is connected to the junction of diodes D3 and D4. The junction of diodes D1 and D3 are connected to ground. A capacitor C11 is preferably connected on one side to the D2-D4 junction and on the other side of the capacitor C11 to the D1-D3 junction in order to isolate the voltages at each side of the rectifier from each other. Therefore, any negative voltages applied to the D1-D2 junction or the D3-D4 junction will pass through diodes D1 or D3 respectively to ground. Positive voltages applied to the D1-D2 junction or the D3-D4 junction will pass through diodes D2 or D4 respectively to the D2-D4 junction. The rectified waveform is shown in
The circuit also comprises a voltage regulator U2, which controls magnitude of the input electrical signal downstream of the rectifier 31. The rectifier 31 is electrically connected to a voltage regulator U2 with the D2-D4 junction connected to the Vin pin of the voltage regulator U2 and with the D1-D3 junction connected to ground and the ground pin of the voltage regulator U2. The voltage regulator U2 comprises for example a LT1121 chip voltage regulator U2 with a 3.3 volts DC output. The output voltage waveform is shown in
The output of the voltage regulator U2 is preferably used to power an encoder 40 or tone generator comprising a peripheral interface controller (PIC) microcontroller that generates a pulsed tone. This pulsed tone modulates an RF generator section 50 which radiates an RF signal using a tuned loop antenna 60. The signal radiated by the loop antenna is intercepted by an RF receiver 270 and a decoder 280 which generates a relay pulse to activate the relay 290.
The output of the voltage regulator U2 is connected to a PIC microcontroller, which acts as an encoder 40 for the electrical output signal of the regulator U2. More specifically, the output conductor for the output voltage signal (nominally 3.3 volts) is connected to the input pin of the programmable encoder 40. Types of register-based PIC microcontrollers include the eight-pin PIC12C5XX and PIC12C67x, baseline PIC16C5X, midrange PIC16CXX and the high-end PIC17CXX/PIC18CXX. These controllers employ a modified Harvard, RISC architecture that support various-width instruction words. The datapaths are 8 bits wide, and the instruction widths are 12 bits wide for the PIC16C5X/PIC12C5XX, 14 bits wide for the PIC12C67X/PIC16CXX, and 16 bits wide for the PIC17CXX/PIC18CXX. PICMICROS are available with one-time programmable EPROM, flash and mask ROM. The PIC17CXX/PIC18CXX support external memory. The encoder 40 comprises for example a PIC model 12C671. The PIC12C6XX products feature a 14-bit instruction set, small package footprints, low operating voltage of 2.5 volts, interrupts handling, internal oscillator, on-board EEPROM data memory and a deeper stack. The PIC12C671 is a CMOS microcontroller programmable with 35 single word instructions and contains 1024×14 words of program memory, and 128 bytes of user RAM with 10 MHz maximum speed. The PIC12C671 features an 8-level deep hardware stack, 2 digital timers (8-bit TMR0 and a Watchdog timer), and a four-channel, 8-bit ND converter.
The output of the PIC may include square, sine or saw waves or any of a variety of other programmable waveforms. Typically, the output of the encoder 40 is a series of binary square waveforms (pulses) oscillating between 0 and a positive voltage, preferably +3.3 VDC. The duration of each pulse (pulse width) is determined by the programming of the encoder 40 and the duration of the complete waveform is determined by the duration of output voltage pulse of the voltage regulator U2. A capacitor C5 is preferably connected on one end to the output of the voltage regulator U2, and on the other end to ground to act as a filter between the voltage regulator U2 and the encoder 40.
Thus, the use of an IC as a tone generator or encoder 40 allows the encoder 40 to be programmed with a variety of values. The encoder 40 is capable of generating one of many unique encoded signals by simply varying the programming for the output of the encoder 40. More specifically, the encoder 40 can generate one of a billion or more possible codes. It is also possible and desirable to have more than one encoder 40 included in the circuit in order to generate more than one code from one transducer 12 or transmitter. Alternately, any combination of multiple transducers and multiple pulse modification subcircuits may be used together to generate a variety of unique encoded signals. Alternately the encoder 40 may comprise one or more inverters forming a series circuit with a resistor and capacitor, the output of which is a square wave having a frequency determined by the RC constant of the encoder 40.
The DC output of the voltage regulator U2 and the coded output of the encoder 40 are connected to an RF generator 50. A capacitor C6 may preferably be connected on one end to the output of the encoder 40, and on the other end to ground to act as a filter between the encoder 40 and the RF generator 50. The RF generator 50 consists of tank circuit connected to the encoder 40 and voltage regulator U2 through both a bipolar junction transistor (BJT) Q1 and an RF choke L1. More specifically, the tank circuit consists of a resonant circuit comprising an inductor L2 and a capacitor C8 connected to each other at each of their respective ends (in parallel). Either the capacitor C8 or the inductor L2 or both may be tunable in order to adjust the frequency of the tank circuit. An inductor L1 acts as an RF choke, with one end of the inductor L1 connected to the output of the voltage regulator U2 and the opposite end of the inductor L1 connected to a first junction of the L2-C8 tank circuit. Preferably, the RF choke inductor L1 is an inductor with a diameter of approximately 0.125 inches and turns on the order of thirty and is connected on a loop of the tank circuit inductor L2. The second and opposite junction of the L2-C8 tank circuit is connected to the collector of BJT 01. The base of the BJT Q1 is also connected through resistor R2 to the output side of the encoder 40. A capacitor C7 is connected to the base of a BJT Q1 and to the first junction of the tank circuit. Another capacitor C9 is connected in parallel with the collector and emitter of the BJT Q1. This capacitor C9 improves the feedback characteristics of the tank circuit. The emitter of the BJT Q1 is connected through a resistor R3 to ground. The emitter of the BJT Q1 is also connected to ground through capacitor C10 which is in parallel with the resistor R3. The capacitor C10 in parallel with the resistor R3 provides a more stable conduction path from the emitter at high frequencies.
The RF generator 50 works in conjunction with a tuned loop antenna 60. In the preferred embodiment, the inductor L2 of the tank circuit serves as the loop antenna 60. Alternatively, the inductor/loop antenna L2 comprises a single rectangular loop of copper wire having an additional smaller loop or jumper 61 connected to the rectangular loop L2. Adjustment of the shape and angle of the smaller loop 61 relative to the rectangular loop L2 is used to increase or decrease the apparent diameter of the inductor L2 and thus tunes the RF transmission frequency of the RF generator 50. In an alternate embodiment, a separate tuned antenna may be connected to the second junction of the tank circuit. Most preferably, the antenna 60 comprises a metallic wire whose length determines the radiated strength of the RF signal. This wire may have one or more “S-bends” to increase the overall length of the antenna. The antenna 60 is affixed, preferably with hot glue, to the top face 70 of the base 70. Attachment of the antenna 60 to the base affects the impedance of the antenna and the characteristics of the radiated signal. A metallic shield 500 may be provided adjacent the antenna 60 on the opposite side 70b of the base 70 to reduce interference with the RF signal.
In operation: The positive voltage output from the voltage regulator U2 is connected the encoder 40 and the RF choke inductor L1. The voltage drives the encoder 40 to generate a coded square wave output, which is connected to the base of the BJT Q1 through resistor R2. When the coded square wave voltage is zero, the base of the BJT Q1 remains de-energized, and current does not flow through the inductor L1. When the coded square wave voltage is positive, the base of the BJT Q1 is energized through resistor R2. With the base of the BJT Q1 energized, current is allowed to flow across the base from the collector to the emitter and current is also allowed to flow across the inductor L1. When the square wave returns to a zero voltage, the base of the BJT Q1 is again de-energized.
When current flows across the choke inductor L1, the tank circuit capacitor C8 charges. Once the tank circuit capacitor C8 is charged, the tank circuit begins to resonate at the frequency determined by the circuit's LC constant. For example, a tank circuit having a 7 picofarad capacitor and an inductor L2 having a single rectangular loop measuring 0.7 inch by 0.3 inch, the resonant frequency of the tank circuit is 310 MHz. The choke inductor L1 prevents RF leakage into upstream components of the circuit (the PIC) because changing the magnetic field of the choke inductor L1 produces an electric field opposing upstream current flow from the tank circuit. To produce an RF signal, charges have to oscillate with frequencies in the RF range. Thus, the charges oscillating in the tank circuit inductor/tuned loop antenna L2 produce an RF signal of preferably 310-430 MHz. As the square wave output of the inverter turns the BJT Q1 on and off, the signal generated from the loop antenna 60 comprises a pulsed RF signal having a duration of 100-250 milliseconds and a pulse width determined by the encoder 40, (typically of the order of 0.1 to 5.0 milliseconds thus producing 20 to 2500 pulses at an RF frequency of approximately 310-430 MHz. The RF generator section 50 is tunable to multiple frequencies. Therefore, not only is the transmitter capable of a great number of unique codes, it is also capable of generating each of these codes at a different frequency, which greatly increases the number of possible combinations of unique frequency-code signals.
The RF generator 50 and antenna 60 work in conjunction with an RF receiver 270. More specifically, an RF receiver 270 in proximity to the RF transmitter 60 (within 300 feet) can receive the pulsed RF signal transmitted by the RF generator 50. The RF receiver 270 comprises a receiving antenna 270 for intercepting the pulsed RF signal (tone). The tone generates a pulsed electrical signal in the receiving antenna 270 that is input to a microprocessor chip that acts as a decoder 280. The decoder 280 filters out all signals except for the RF signal it is programmed to receive, e.g., the signal generated by the RF generator 50. An external power source is also connected to the microprocessor chip/decoder 280. In response to the intercepted tone from the RF generator 50, the decoder chip produces a pulsed electrical signal. The external power source connected to the decoder 280 augments the pulsed voltage output signal developed by the chip. This augmented (e.g., 120VAC) voltage pulse is then applied to a conventional relay 290 for changing the position of a switch within the relay. Changing the relay switch position is then used to turn an electrical device with a bipolar switch on or off, or toggle between the several positions of a multiple position switch. Zero voltage switching elements may be added to ensure the relay 290 activates only once for each depression and recovery cycle of the flextensional transducer element 12.
Electronic Digital Switching System
An electronic digital entry system comprises one or more electroactive devices 12 and keys or a keypad for entry of a digital code or sequence, as well as an circuit for using the electrical energy of the electroactive device(s) 12 and interpretation of the sequence entered into the keypad.
Referring again to
The individual buttons 321, 322 on the keypad 320 are easily depressible buttons that may take a variety of forms. As an example of types of keypad buttons that may be used are flat membrane switches 321, 322, and domed membrane switches 321, 322 and may further include LEDs or the like as indicators of the switch or button state. For example, flat membrane switches 321, 322 comprise a button overlay material of polyester or polycarbonate with circuit connectors installed thereunder and are depressible with an applied force of 70-120 grams. Domed membrane switches 321, 322 have a better sense of touch and may be actuated with an operating force of 150-400 grams. The overlay material comprises a flexible yet durable material such as plastic, polyester or polycarbonate with electrical connectors installed thereunder.
Basically, a membrane switch 321, 322 as its name implies an electrical switch created on a thin film or membrane. They are typically low power with maximum current ratings of around 1/10 of an amp. The circuitry for these devices is often somewhat elaborate since they frequently provide connections for a host of different input functions. Perhaps the most common application for membrane switches 321, 322 is in a keyboard of some type. While not all keyboards are made of flexible materials, a great many are. The most common layouts are matrix type (i.e., rows and columns) and common line connections (i.e., a common trace plus some number of switches). Other structures are possible depending on the needs of the user including integration of electronic circuits, including passives devices, such as resistors, and land patterns for component mounting.
The conductor material used for membrane switches 321, 322 varies by application. Copper and polymer thick film (PTF) inks are the most common choices. Cost is normally a key factor when making the choice. Because of this, a substantial number of membrane switches have screen-printed PTF conductors consisting of metal-filled ink. Obviously, the normally much lower conductivity of printed inks limits the conductivity but they are not normally meant to carry current. Rather they are designed to send a simple signal pulse. Copper is employed when there is need to solder devices to the membrane or higher conductivity is needed, however, conductive adhesives have proven quite acceptable in most applications.
The switch-life of a membrane contact can vary significantly from several thousand to many millions. The life-determining factors are many, and include such matters as materials of construction, contact design, switch travel, and operating conditions among many others.
One of the key elements of membrane switch design is involved in determining tactile feedback. This is that little snap or click that can be felt when a switch is pressed. Determining the right amount of force to be applied (the actuation pressure) is both an art and a science. There are basically two approaches to getting tactile feed back: metal dome contacts and polymer dome contacts. Metal dome tactile switches have spring metal dome over the contact area. When pressed, it snaps down to complete a circuit and snaps back when released. The shape and thickness of the metal (commonly spring stainless steel) will determine actuation force. They offer a long life but are not well suited to use with flex circuits. In contrast, polymer dome switches are embossed into the plastic film overlying the circuit. It is possible to get a good tactile feel from such contact, and though their life expectation is heavily influenced by their use environment, they can still endure millions of cycles. Furthermore, they have the advantage when it comes to cost since they reduce the number of parts, thus assembly time and complexity. Depending on the application, one can opt to not use tactile feedback. To this end, an auditory response method may be employed such as a small beep. Because of their extreme simplicity, these tend to be the lowest cost contacts of all.
Basic membrane switch contact designs are shown without an over layer in
The contact area design is another important and interesting element of a membrane switch. Contact finish can vary. Gold, nickel, silver and even graphite have been used. The layout will vary with the type of contact used. For example, for a shorting contact, interdigitated fingers are often used. However, when a metal dome contact is employed, a central contact with a surrounding ring is frequently seen.
In one embodiment of the invention a polyester or polycarbonate overlay material having twelve switch buttons 321, 322 thereon is used with an individual THUNDER element 12 lying beneath each button. As shown in
The overlay of buttons and the underlying THUNDER element(s) are preferably retained in the face plate section 330 of the keypad assembly. The face plate section 330 of the keypad assembly has one or more recesses 331, 332 therein which retain the overlay material and underlying THUNDER element(s). The face plate section 330 is preferably the same shape as the overlay 320, and more preferably a square plate having a flat surface and a lip around the periphery of the flat surface which forms the recess 331, 332. The recess 331, 332 is suitable for retaining the overlay 320 about its edge between the flat surface of the face plate and the lip. In the embodiment of
The face plate may also comprise additional recesses for retaining the individual smaller THUNDER elements. The recesses are 331, 332, 335-7 in the flat surface of the face plate and are the substantially the same shape as the THUNDER element retained therein. The shape of the THUNDER button recesses allows them to be retained within the recess yet allows some room for the THUNDER element to extend further thereinto when the THUNDER element is deformed by the pressing of a membrane switch. Preferably, the recess 331, 332, 335-7 retains the edges of the THUNDER element 12 in its neutral arcuate shape and also deep enough to accommodate the THUNDER element in its deformed flattened state. In the embodiment of
In operation, when one button 321, 322 is pressed, the THUNDER element 12 underlying the button or buttons is deformed. More specifically, when a button 321 of the keypad 320 of
As previously mentioned, the applied force causes the piezoelectric actuator 12 to deform. By virtue of the piezoelectric effect, the deformation of the piezoelectric element 67 generates an instantaneous voltage between the faces 12a and 12c of the actuator 12, which produces a pulse of electrical energy. Furthermore, when the force is removed from the piezoelectric actuator 12, the actuator 12 recovers its original arcuate shape. This is because the substrate or prestress layers 64 and 68 to which the ceramic 67 is bonded exert a compressive force on the ceramic 67, and the actuator 12 thus has a coefficient of elasticity that causes the actuator 12 to return to its undeformed neutral state. On the recovery stroke of the actuator 12, the ceramic 67 returns to its undeformed state and thereby produces another electrical pulse of opposite polarity. The downward (applied) or upward (recovery) strokes should cause a force over a distance that is of sufficient magnitude to create the desired electrical pulse. The duration of the recovery stroke, and therefore the duration of the pulse produced, is preferably in the range of 5-100 milliseconds, depending on the amount of force applied to the actuator 12.
The electrical signal generated by the actuator 12 is applied to downstream circuit elements via wires 14 connected to the actuator 12. More specifically, a first wire 14 is connected to the electrode 90 which extends into the recess 80 and contacts the electrode 68 on the convex face 12a of the actuator 12. Preferably the wire 14 is connected to the electrode 90 outside of the recess close to the end of the base plate 70 opposite the end having the clamping member 75. A second wire 14 is connected directly to the first prestress layer 64, i.e., the substrate 64 which acts as an electrode on the concave face 12c of the actuator 12.
Referring to
The circuit also comprises a voltage regulator U2, which controls magnitude of the input electrical signal downstream of the rectifier 31. The rectifier 31 is electrically connected to a voltage regulator U2 with the D2-D4 junction connected to the Vin pin of the voltage regulator U2 and with the D1-D3 junction connected to ground and the ground pin of the voltage regulator U2. The voltage regulator U2 comprises for example a LT1121 chip voltage regulator U2 with a 3.3 volts DC output. The output voltage waveform is shown in
Preferably however, the output voltage is connected through an encoder 40 to an RF generation section 50 of the circuit.
Referring now to
A keypad to register successive button entries for a coded entry system may be disclosed. Input power to the circuit is provided by the output of the voltage regulator. When an acceptable code is entered into the self powered keypad, the keypad circuit or logic component sends an actuation signal to a switching device (such as a transistor) located between the storage device (capacitor or rechargeable battery) and the entry mechanism or other switching device. The switching device is normally in the open position when no code or the wrong code has been entered. After the correct code is entered the logic component sends a signal to the switching device to close. This allows the capacitor/battery to discharge through the switch to the entry mechanism.
The keypad logic circuit components comprise an IC which is a quad 2 input “AND” gate, such as a CMOS 4081. These gates only produce a HIGH output, when BOTH the inputs are HIGH. When the key wired to ‘E’ is pressed, current through R1 and D1 switches Q5 on. The relay energizes; and Q5 is latched on by R8. Thus, the alarm is set by pressing a single key, say one of the two non-numeric symbols.
The circuit will switch off when the 4 keys connected to “A,B,C,D” are pushed in the right order. The circuit works because each gate ‘Stands’ upon its predecessor. If any key other than the correct key is pushed, then gate 1 is knocked out of the stack, and the code entry fails. Pin 1 is held high by R4. This ‘Enables’ gate 1; and when button ‘A’ is pressed, the output at pin 3 will go high. This output does two jobs. It locks itself ‘ON’ through R2 and it ‘Enables’ gate 2, by taking pin 5, high. Now, if ‘B’ is pressed, the output of gate 2, at pin 4 will go high. This output does two jobs. It locks itself ‘ON’ through R3 and it ‘Enables’ gate 3 by taking pin 12 high.
Now, if ‘C’ is pressed, the output of gate 3 will lock itself ‘ON’ through R5 and, by taking pin 8 high, ‘Enable’ gate 4. Pressing ‘D’ causes gate 4 to do the same thing; only this time its output, at pin 10, turns Q4 ‘ON’. This takes the base of Q5 to ground, switching it off and letting the relay drop out.
Any keys not connected to ‘A B C D E’ are wired to the base of Q1. Whenever ‘E’ or one of these other keys is pressed, pin 1 is taken low and the circuit is reset. In addition, if ‘C’ or ‘D’ is pressed out of sequence, then Q2 or Q3 will take pin 1 low and the circuit will reset. Thus nothing happens until ‘A’ is pressed. Then if any key other than ‘B’ is pressed, the circuit will reset. Similarly, after ‘B’, if any key other than ‘C’ is pressed, the circuit will reset. The same reasoning also applies to ‘D’. The Keypad needs to be the kind with a common terminal and a separate connection to each key. On a 12 key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. Wire the common to R1 and your chosen code to ‘A B C D’. Wire ‘E’ to the key you want to use to switch the alarm on. All the rest go to the base of Q1.
The code can be chosen to include the non-numeric symbols. The number of combinations of codes available is in excess of 10 000 with a 12 key pad. If a more secure code desired, one can add another 4081 and continue the process of enabling subsequent gates. Also one may simply use a bigger keypad with more “WRONG” keys. It is required that the 4k7 resistors protect the junctions while providing enough current to turn the transistors fully on. Capacitors (C1 C2 C3 C4 C5) are there to slow response time and overcome any contact bounce.
Referring to
For extra security these systems may turn off and sound a local alarm after a preset number of wrong combinations. One can put a temporary code in for a baby-sitter or house-keeper and then erase it all by yourself right at the keypad. One can control an electric garage door and unlike the very cheap keypads being sold through the home centers, with this keypad one can have a high security locking system that can't be opened. One can have more than one combination so each person will have a unique code. When controlling an electric lock or strike the relay can be set so it's timed to open or close for a pre-determined period. This is called a momentary closure of the relay. Most keypads can also be set for latching, which means that when the correct code is entered, the relay will fire (open or close). It will remain that way until the code is entered again. With the master code one can erase and add new codes any time. You can hook up more than one unit to control a lock such as one on the outside and one on the inside similar to a double cylinder lock.
Some of these keypads are actually part of a two piece system in that the keypad is attached to a separate small box that contains the electronics. These two part systems are inherently more secure because the box is installed inside in a secure are. The two part systems will specify this. Some applications require a special output format know as Wiegand. The Wiegand output is different from the output of most keypads. Most keypads are made to open or close a relay to activate a lock. A Weigand format keypad will instead produce a certain voltage pattern that will be recognized by the systems electronics. Many of these keypads can also be ordered in the Wiegand format and in addition a very secure 26 bit format, at about the same price as regular keypads.
Referring now to
Referring again to
The output of the voltage regulator U2 is connected to a PIC microcontroller, which acts as an encoder 40 for the electrical output signal of the regulator U2. More specifically, the output conductor for the output voltage signal (usually 3.3 volts, but can range from 1.7-5.0 volts) is connected to the input pin of the programmable encoder 40. Types of register-based PIC microcontrollers include the eight-pin PIC12C5XX and PIC12C67X, baseline PIC16C5X, midrange PIC16CXX and the high-end PIC17CXX/PIC18CXX. These controllers employ a modified Harvard, RISC architecture that support various-width instruction words. The datapaths are 8 bits wide, and the instruction widths are 12 bits wide for the PIC16C5X/PIC12C5XX, 14 bits wide for the PIC12C67X/PIC16CXX, and 16 bits wide for the PIC17CXX/PIC18CXX. PICMICROS are available with one-time programmable EPROM, flash and mask ROM. The PIC17CXX/PIC18CXX support external memory. The encoder 40 comprises for example a PIC model 12C671. The PIC12C6XX products feature a 14-bit instruction set, small package footprints, low operating voltage of 2.5 volts, interrupts handling, internal oscillator, on-board EEPROM data memory and a deep stack. The PIC12C671 is a CMOS microcontroller programmable with 35 single word instructions and contains 1024×14 words of program memory, and 128 bytes of user RAM with 10 MHz maximum speed. The PIC12C671 features an 8-level deep hardware stack, 2 digital timers (8-bit TMR0 and a Watchdog timer), and a four-channel, 8-bit A/D converter.
The output of the PIC may include square, sine or saw waves or any of a variety of other programmable waveforms. Typically, the output of the encoder 40 is a series of binary square waveforms (pulses) oscillating between 0 and a positive voltage, preferably +3.3 VDC. The duration of each pulse (pulse width) is determined by the programming of the encoder 40. The duration of the complete waveform is determined by the duration of output voltage pulse of the voltage regulator U2. A capacitor C5 is preferably be connected on one end to the output of the voltage regulator U2, and on the other end to ground to act as a filter between the voltage regulator U2 and the encoder 40.
Thus, the use of an IC as a tone generator or encoder 40 allows the encoder 40 to be programmed with a variety of values. The encoder 40 is capable of generating a multiplicity of unique encoded signals by simply varying the programming for the output of the encoder 40. More specifically, the encoder 40 can generate any one of a 32 bit combination of (5 billion or more) possible codes. It is also possible and desirable to have more than one encoder 40 included in the circuit in order to generate more than one code from one actuator or transmitter. Alternately, any combination of multiple actuators and multiple pulse modification subcircuits may be used together to generate a variety of unique encoded signals. Alternately the encoder 40 may comprise one or more inverters forming a series circuit with a resistor and capacitor, the output of which is a square wave having a frequency determined by the RC constant of the encoder 40.
Referring to
A capacitor C6 may preferably be connected on one end to the output of the encoder 40, and on the other end to ground to act as a filter between the encoder 40 and the RF generator 50. The RF generator 50 consists of tank circuit connected to the encoder 40 and voltage regulator U2 through both a bipolar junction transistor (BJT) Q1 and an RF choke. More specifically, the tank circuit consists of a resonant circuit comprising an inductor L2 and a capacitor C8 connected to each other at each of their respective ends (in parallel). Either the capacitor C8 or the inductor L2 or both may be tunable in order to adjust the frequency of the tank circuit. An inductor L1 acts as an RF choke, with one end of the inductor L1 connected to the output of the voltage regulator U2 and the opposite end of the inductor L1 connected to a first junction of the L2-C8 tank circuit. Preferably, the RF choke inductor L1 is an inductor with a diameter of approximately 0.125 inches and turns on the order of thirty and is connected on a loop of the tank circuit inductor L2. The second and opposite junction of the L2-C8 tank circuit is connected to the collector of BJT Q1. The base of the BJT Q1 is also connected through resistor R2 to the output side of the encoder 40. A capacitor C7 is connected to the base of a BJT Q1 and to the first junction of the tank circuit. Another capacitor C9 is connected in parallel with the collector and emitter of the BJT Q1. This capacitor C9 improves the feedback characteristics of the tank circuit. The emitter of the BJT Q1 is connected through a resistor R3 to ground. The emitter of the BJT Q1 is also connected to ground through capacitor C10 which is in parallel with the resistor R3. The capacitor C10 in parallel with the resistor R4 provides a more stable conduction path from the emitter at high frequencies.
Referring again to
In operation: The positive voltage output from the voltage regulator U2 is connected the encoder 40 via a default pin and to one or more different pins through one or more respective membrane switches 321, 322. The positive voltage output from the voltage regulator U2 is also connected the RF choke inductor L1. The voltage drives the encoder 40 to generate a coded square wave output (which code depends on the pin energized), which is connected to the base of the BJT Q1 through resistor R2. When the coded square wave voltage is zero, the base of the BJT Q1 remains de-energized, and current does not flow through the inductor L1. When the coded square wave voltage is positive, the base of the BJT Q1 is energized through resistor R2. With the base of the BJT Q1 energized, current is allowed to flow across the base from the collector to the emitter and current is also allowed to flow across the inductor L1. When the square wave returns to a zero voltage, the base of the BJT Q1 is again de-energized.
When current flows across the choke inductor L1, the tank circuit capacitor C8 charges. Once the tank circuit capacitor C8 is charged, the tank circuit begins to resonate at the frequency determined by the circuit's LC constant. For example, a tank circuit having a 7 picofarad capacitor and an inductor L2 having a single rectangular loop measuring 0.7 inch by 0.3 inch, the resonant frequency of the tank circuit is 310 MHz. The choke inductor L1 prevents RF leakage into upstream components of the circuit (the PIC) because changing the magnetic field of the choke inductor L1 produces an electric field opposing upstream current flow from the tank circuit. To produce an RF signal, charges have to oscillate with frequencies in the RF range. Thus, the charges oscillating in the tank circuit inductor/tuned loop antenna L2 produce an RF signal of preferably 310 MHz. As the square wave output of the inverter turns the BJT Q1 on and off, the signal generated from the loop antenna 60 comprises a pulsed RF signal having a duration of 10-250 milliseconds and a pulse width determined by the encoder 40, (typically of the order of 0.1 to 5.0 milliseconds thus producing 20 to 2500 pulses at an RF frequency of approximately 310 MHz. The range of the radiated signal is from 200-1000 MHz and most preferably approximately 430 Mhz. The RF generator section 50 is tunable to multiple frequencies. Therefore, not only is the transmitter capable of a great number of unique codes, it is also capable of generating each of these codes at a different frequency, which greatly increases the number of possible combinations of unique frequency-code signals.
The RF generator 50 and antenna 60 work in conjunction with an RF receiver 101. More specifically, an RF receiver 101 in proximity to the RF transmitter 60 (within 300 feet) can receive the pulsed RF signal transmitted by the RF generator 50. The RF receiver 101 comprises a receiving antenna 270 for intercepting the pulsed RF signal (tone or code). The tone generates a pulsed electrical signal in the receiving antenna 270 that is input to a microprocessor chip that acts as a decoder 280. The decoder 280 filters out all signals except for the RF signal it is programmed to receive, e.g., the signal generated by the RF generator 50. An external power source is also connected to the microprocessor chip/decoder 280. In response to the intercepted code from the RF generator 50, the decoder chip produces a pulsed electrical signal. The external power source connected to the decoder 280 augments the pulsed voltage output signal developed by the chip. This augmented (e.g., 120VAC) voltage pulse is then applied to a conventional relay 290 for changing the position of a switch within the relay. Changing the relay switch position is then used to turn an electrical device with a bipolar switch on or off, or toggle between the several positions of a multiple position switch. Zero voltage switching elements may be added to ensure the relay 290 activates only once for each depression and recovery cycle of the flextensional transducer element 12.
Switch Initiator System with Trainable Receiver
Several different RF transmitters may be used that generate different tones for controlling relays that are tuned to receive that tone. In another embodiment, digitized RF signals may be coded and programmable (as with a garage door opener) to only activate a relay that is coded with that digitized RF signal. In other words, the RF transmitter is capable of generating at least one tone, but is preferably capable of generating multiple tones. Most preferably, each transmitter is programmed with one or more unique coded signals. This is easily done, since programmable ICs for generating the tone can have over 230 possible unique signal codes which is the equivalent of over 1 billion codes. Most preferably the invention comprises a system of multiple transmitters and one or more receivers for actuating building lights, appliances, security systems and the like. In this system for remote control of these devices, an extremely large number of codes are available for the transmitters for operating the lights, appliances and/or systems and each transmitter has at least one unique, permanent and nonuser changeable code. The receiver and controller module at the lights, appliances and/or systems is capable of storing and remembering a number of different codes corresponding to different transmitters such that the controller can be programmed so as to actuated by more than one transmitted code, thus allowing two or more transmitters to actuate the same light, appliance and/or system.
The remote control system includes a receiver/controller for learning a unique code of a remote transmitter to cause the performance of a function associated with the system, light or appliance with which the receiver/controller module is associated. The remote control system is advantageously used, in one embodiment, for interior or exterior lighting, household appliances or security system. Preferably, a plurality of transmitters is provided wherein each transmitter has at least one unique and permanent non-user changeable code and wherein the receiver can be placed into a program mode wherein it will receive and store two or more codes corresponding to two or more different transmitters. The number of codes which can be stored in transmitters can be extremely high as, for example, greater than one billion codes. The receiver has a decoder module therein which is capable of learning many different transmitted codes, which eliminates code switches in the receiver and also provides for multiple transmitters for actuating the light or appliance. Thus, the invention makes it possible to eliminate the requirements for code selection switches in the transmitters and receivers.
Referring to
In the invention, each transmitter, such as transmitters 126 and 128, has at least one unique code which is determined by the tone generator/encoder 40 contained in the transmitter. The receiver unit 101 is able to memorize and store a number of different transmitter codes which eliminates the need of coding switches in either the transmitter or receiver which are used in the prior art. This also eliminates the requirement that the user match the transmitter and receiver code switches. Preferably, the receiver 101 is capable of receiving many transmitted codes, up to the available amount of memory locations 247 in the microprocessor 244, for example one hundred or more codes.
When the controller 290 for the light or appliance is initially installed, the switch 222 is moved to the program mode and the first transmitter 126 is energized so that the unique code of the transmitter 126 is transmitted. This is received by the receiver module 101 having an antenna 270 and decoded by the decoder 280 and supplied to the microprocessor unit 244. The code of the transmitter 126 is then supplied to the memory address storage 247 and stored therein. Then if the switch 222 is moved to the operate mode and the transmitter 126 energized, the receiver 270, decoder 280 and the microprocessor 244 will compare the received code with the code of the transmitter 126 stored in the first memory location in the memory address storage 247 and since the stored memory address for the transmitter 126 coincides with the transmitted code of the transmitter 126 the microprocessor 244 will energize the controller mechanism 290 for the light or appliance to energize de-energize or otherwise operate the device.
In order to store the code of the second transmitter 128 the switch 222 is moved again to the program mode and the transmitter 128 is energized. This causes the receiver antenna 270 and decoder 280 to decode the transmitted signal and supply it to the microprocessor 244 which then supplies the coded signal of the transmitter 128 to the memory address storage 247 where it is stored in a second address storage location. Then the switch 222 is moved to the operate position and when either of the transmitters 126 and 128 are energized, the receiver decoder 280 and microprocessor 244 will energize the controller mechanism 290 for the light or appliance to energize de-energize or otherwise operate the device. Alternately, the signal from the first transmitter 126 and second transmitter 128 may cause separate and distinct actions to be performed by the controller mechanism 290.
Thus, the codes of the transmitters 126 and 128 are transmitted and stored in the memory address storage 247 during the program mode after which the system, light or appliance controller 290 will respond to either or both of the transmitters 126 and 128. Any desired number of transmitters can be programmed to operate the system, light or appliance up to the available memory locations in the memory address storage 247. In addition, not all transmitters need be self-powered. That is to say, a battery or AC powered transmitter may be installed that “speaks the same language” as the other transmitters, and as such will transmit a code that the receiver is capable of responding to. All that is necessary for such a powered transmitter is that the regulated input voltage pass through and encoder and RF transmitter circuit that uses the same coding (i.e., unique codes) as well as an RF transmission circuit that is modulated with the code (and any other communications protocols) described further herein below and transmitting at the same frequency and pulsewidth as the other RF transmission circuits described above. Thus, a self-powered system may be augmented by transmitters that are powered through a separate AC or DC voltage.
This invention eliminates the requirement that binary switches be set in the transmitter or receiver as is done in systems of the prior art. The invention also allows a controller to respond to a number of different transmitters because the specific codes of a number of the transmitters are stored and retained in the memory address storage 247 of the receiver module 101.
In yet another more specific embodiment of the invention, each transmitter 126 or 128 contains two or more unique codes for controlling a system, light or appliance. One code corresponds in the microprocessor to the “on” position and another code corresponds in the microprocessor 244 to the “off” position of the controller 290. Alternately, the codes may correspond to “more” or “less” respectively in order to raise or lower the volume of a sound device or to dim or undim lighting for example. Lastly, the unique codes in a transmitter 126 or 128 may comprise four codes which the microprocessor interprets as “on”, “off”, “more” and “less” positions of the controller 290, depending on the desired setup of the switches. Alternatively, a transmitter 126 or 128 may only have two codes, but the microprocessor 244 interprets repeated pushes of “on” or “off” signals respectively to be interpreted as dim up and dim down respectively.
In another embodiment of the invention, receiver modules 101 may be trained to accept the transmitter code(s) in one-step. Basically, the memory 247 in the microprocessor 244 of the receiver modules 101 will have “slots” where codes can be stored. For instance one slot may be for all of the codes that the memory 247 accepts to be turned on, another slot for all the off codes, another all the 30% dimmed codes, etc.
Each transmitter 126 has a certain set of codes. For example one transmitter may have just one code, a “toggle” code, wherein the receiver module 101 knows only to reverse its current state, if it's on, turn off, and if it's off, turn on. Alternatively, a transmitter 126 may have many codes for the complex control of appliances. Each of these codes is “unique”. The transmitter 126 sends out its code set in a way in which the receiver 101 knows in which slots to put each code. Also, with the increased and longer electrical signal that can be generated in the transmitter 126, a single transmission of a code set is achievable even with mechanically produced voltage. As a back-up, if this is not true, and if wireless transmission uses up more electricity than is available, some sort of temporary wired connection (jumper not shown) between each transmitter and receiver target is possible. Although the disclosed embodiment shows manual or mechanical interaction with the transmitter and receiver to train the receiver, it is yet desirable to put the receiver in reprogram mode with a wireless transmission, for example a “training” code.
In yet another embodiment of the invention, the transmitter 126 may have multiple unique codes and the transmitter randomly selects one of the multitude of possible codes, all of which are programmed into the memory allocation spaces 247 of the microprocessor 244.
In yet another embodiment of the invention, the transmitter 126 signal need not be manually operated or triggered, but may as easily be operated by any manner of mechanical force, i.e., the movement of a window, door, safe, foot sensor, etc. and that a burglar alarm sensor might simultaneously send a signal to the security system and a light in the intruded upon room. Likewise, the transmitter 126 may be combined with other apparatus. For example, a transmitter 126 may be located within a garage door opener which can also turn on one or more lights in the house, when the garage door opens.
Furthermore, the transmitters 126, 128 can transmit signals to a central system or repeater which re-transmits the signals by wired or wireless means to lights and appliances. In this manner, one can have one transmitter/receiver set, or many transmitters interacting with many different receivers, some transmitters talking to one or more receivers and some receivers being controlled by one or more transmitters, thus providing a broad system of interacting systems and wireless transmitters. Also, the transmitters and receivers may have the capacity of interfacing with wired communications like SMARTHOME or BLUETOOTH, and ZIGBEE.
It is seen that the present invention allows a receiving system to respond to one of a plurality of transmitters which have different unique codes which can be stored in the receiver during a program mode. Each time the “program mode switch” 222 is moved to the program position, a different storage can be connected so that the new transmitter code would be stored in that address. After all of the address storage capacity has been used additional codes would erase all old codes in the memory address storage before storing a new one.
Referring now to FIGS. 18 and 20-21: While in the preferred embodiment of the invention, the actuation means has been described as from mechanical to electric, it is within the scope of the invention to include batteries in the transmitter to power or supplement the power of the transmitter. For example, long life rechargeable batteries 430 may be included in the transmitter circuitry and may be recharged through the electromechanical transducers 12. These rechargeable batteries 430 may thus provide backup power to the transmitter 50. The circuits illustrated in the figures are the same as those described herein above, with the exception of the addition of rechargeable batteries 430 in the circuit. In the circuit of
Referring now to FIGS. 18 and 20-21: The circuit of
Referring again to FIGS. 18 and 20-21: In another embodiment of a self-powered transmitter circuit, the rechargeable battery 430 not only provides power for transmission of a coded signal, but also provides power to a low power consumption receiver 450. In the preferred embodiment, the receiver/transmitter comprises a single transceiver 450. The transceiver 450 is electrically connected to the battery. However, in addition to transmitting in response to a trigger signal from the transducer 12 to energize the switch S1, the transceiver 450 will also transmit in response to the receiver portion of the transceiver's reception of an RF signal. In the preferred embodiment of the transceiver based circuit, when the transceiver 450 receives a coded signal corresponding one or more codes stored in the transmitter PIC (i.e., a polling code), then the transmitter portion of the transceiver 450 will transmit its coded RF signal. The transmitter RF code signal may correspond for example, to a transmission code of its current state for use as or to supplement an error detection code or a verification code. The battery supplemented transceivers 450 are preferably made compatible with present low-cost, very low power consumption, two-way, digital wireless communications standards such as ZIGBEE and BLUETOOTH.
In the embodiments of the invention in
The individual buttons 321, 322 are easily depressible buttons that may take a variety of forms. As an example of types of keypad buttons that may be used are flat membrane switches 321, 322 and domed membrane switches 321, 322 and may further include LEDs or the like as indicators of the switch or button state. For example, flat membrane switches 321, 322 comprise a button overlay material 323 (on which is printed the alphanumeric or other command symbol) of polyester or polycarbonate with circuit connectors installed thereunder and are depressible with an applied force of 70-120 grams. Domed membrane switches 321, 322 have a better sense of touch and may be actuated with an operating force of 150-400 grams. The overlay 323 material comprises a flexible yet durable material such as plastic, polyester or polycarbonate with electrical connectors (such as in
Basically, a membrane switch 321, 322 as its name implies an electrical switch created on a thin film or membrane. They are typically low power with maximum current ratings of around 1/10 of an amp. The circuitry for these devices is often somewhat elaborate since they frequently provide connections for a host of different input functions.
The most common application for membrane switches 321, 322 is in a keyboard of some type. While not all keyboards are made of flexible materials, a great many are. The most common layouts are matrix type (i.e., rows and columns) and common line connections (i.e., a common trace plus some number of switches). Other structures are possible depending on the needs of the user including integration of electronic circuits, including passives devices, such as resistors, and land patterns for component mounting.
The conductor material used for membrane switches 321, 322 varies by application. Copper and polymer thick film (PTF) inks are the most common choices. Cost is normally a key factor when making the choice. Because of this, a substantial number of membrane switches have screen-printed PTF conductors consisting of metal-filled ink. Obviously, the normally much lower conductivity of printed inks limits the conductivity but they are not normally meant to carry current. Rather they are designed to send a simple signal pulse. Copper is employed when there is need to solder devices to the membrane or higher conductivity is needed, however, conductive adhesives have proven quite acceptable in most applications. The switch-life of a membrane contact can vary significantly from several thousand to many millions. The life-determining factors are many, and include such matters as materials of construction, contact design, switch travel, and operating conditions among many others.
One of the key elements of membrane switch design is involved in determining tactile feedback. This is that little snap or click that can be felt when a switch is pressed. Determining the right amount of force to be applied (the actuation pressure) is both an art and a science. There are basically two approaches to getting tactile feed back: metal dome contacts and polymer dome contacts. Metal dome tactile switches have spring metal dome over the contact area. When pressed, it snaps down to complete a circuit and snaps back when released. The shape and thickness of the metal (commonly spring stainless steel) will determine actuation force. They offer a long life but are not well suited to use with flex circuits. In contrast, polymer dome switches are embossed into the plastic film overlying the circuit. It is possible to get a good tactile feel from such contact, and though their life expectation is heavily influenced by their use environment, they can still endure millions of cycles. Furthermore, they have the advantage when it comes to cost since they reduce the number of parts, thus assembly time and complexity. Depending on the application, one can opt to not use tactile feedback. To this end, an auditory response method may be employed such as a small beep. Because of their extreme simplicity, these tend to be the lowest cost contacts of all.
Basic membrane switch contact designs are shown without an overlay in
Referring now to
In operation: The positive voltage output from the voltage regulator U2 is connected the encoder 40 via a default pin and to one or more different pins through one or more respective membrane switches 321, 322. The positive voltage output from the voltage regulator U2 is also connected the RF choke inductor L1. The voltage drives the encoder 40 to generate a coded square wave output (which code depends on the pin energized), which is connected to the base of the BJT Q1 through resistor R2. When the coded square wave voltage is zero, the base of the BJT Q1 remains de-energized, and current does not flow through the inductor L1. When the coded square wave voltage is positive, the base of the BJT Q1 is energized through resistor R2. With the base of the BJT Q1 energized, current is allowed to flow across the base from the collector to the emitter and current is also allowed to flow across the inductor L1. When the square wave returns to a zero voltage, the base of the BJT Q1 is again de-energized.
Several different RF transmitters 126, 128 may be used that generate different codes for controlling relays that are trained to receive that code. In another embodiment, digitized RF signals may be coded and programmable (as with a garage door opener) to only activate a relay that is coded with that digitized RF signal. In other words, the RF transmitter is capable of generating at least one code, but is preferably capable of generating multiple codes. Most preferably, each transmitter is programmed with one or more unique coded signals. This is easily done, since programmable ICs for generating the code can have over 230 possible unique signal codes which is the equivalent of over 1 billion codes. Most preferably the invention comprises a system of multiple transmitters and one or more receivers for actuating building lights, appliances, security systems and the like. In this system for remote control of these devices, an extremely large number of codes are available for the transmitters for operating the lights, appliances and/or systems and each transmitter has at least one unique, permanent and non-user changeable code. The receiver and controller module at the lights, appliances and/or systems is capable of storing and remembering a number of different codes corresponding to different transmitters (or different function buttons/membrane switches on a single transmitter) such that the controller can be programmed so as to be actuated by more than one transmitted code, thus allowing two or more transmitters to actuate the same light, appliance and/or system.
The remote control system includes a receiver/controller for learning one or more unique codes of a remote transmitter to cause the performance of a function associated with the system, light or appliance with which the receiver/controller module is associated. The remote control system is advantageously used, in one embodiment, for interior or exterior lighting, household appliances or security system. Preferably, a plurality of transmitters is provided wherein each transmitter has at least one unique and permanent non-user changeable code and wherein the receiver can be placed into a program mode wherein it will receive and store two or more codes corresponding to two or more different transmitters. The number of codes which can be programmed into transmitters can be extremely high as, for example, greater than one billion codes. The receiver has a decoder module therein which is capable of learning many different transmitted codes, which eliminates code switches (dipswitches) in the receiver and also provides for multiple transmitters for actuating the light or appliance. Thus, the invention makes it possible to eliminate the requirements for code selection switches in the transmitters and receivers.
Referring to FIGS. 15 and 17-18: The receiver module includes an antenna 270 for receiving radio frequency transmissions from one or more transmitters 126 and 128 and supplies a received RF signal as an input to a decoder 280 which provides an output to a microprocessor unit 244. The microprocessor unit 244 is connected to a relay device 290 or controller which switches the light or appliance between one of two or more operation modes, i.e., on, off, dim, or some other mode of operation. A switch 222 is mounted on a switch unit 219 connected to the receiver and also to the microprocessor 244. The switch 222 is a two position switch that can be moved between the “operate” and “program” positions to establish operate and program modes.
In the invention, each transmitter, such as transmitters 126 and 128, has at least one unique code which is determined by the tone generator/encoder 40 contained in the transmitter. The receiver unit 101 is able to memorize and store a number of different transmitter codes which eliminates the need of coding switches in either the transmitter or receiver which are used in the prior art. This also eliminates the requirement that the user match the transmitter and receiver code switches. Preferably, the receiver 101 is capable of receiving many transmitted codes, up to the available amount of memory locations 247 in the microprocessor 244, for example one hundred or more codes.
When the controller 290 for the light or appliance is initially installed, the switch 222 is moved or pressed to initiate the program mode and the first transmitter 126 is energized so that the unique code of the transmitter 126 is transmitted. This is received by the receiver module 101 having an antenna 270 and decoded by the decoder 280 and supplied to the microprocessor unit 244. The code of the transmitter 126 is then supplied to the memory address storage 247 and stored therein. Then if the switch 222 is moved to the operate mode and the transmitter 126 energized, the receiver 270, decoder 280 and the microprocessor 244 will compare the received code with the code of the transmitter 126 stored in the first memory location in the memory address storage 247 and since the stored memory address for the transmitter 126 coincides with the transmitted code of the transmitter 126 the microprocessor 244 will energize the controller mechanism 290 for the light or appliance to energize de-energize or otherwise operate the device.
In order to store the code of the second transmitter 128 the switch 222 is moved (or pressed) again to the program mode and the transmitter 128 is energized. This causes the receiver antenna 270 and decoder 280 to decode the transmitted signal and supply it to the microprocessor 244 which then supplies the coded signal of the transmitter 128 to the memory address storage 247 where it is stored in a second address storage location. Then the switch 222 is moved to the operate position and when either of the transmitters 126 and 128 are energized, the receiver antenna 270, decoder 280 and microprocessor 244 will energize the controller mechanism 290 for the light or appliance to energize de-energize or otherwise operate the device. Alternately, the signal from the first transmitter 126 and second transmitter 128 may cause separate and distinct actions to be performed by the controller mechanism 290.
Thus, the codes of the transmitters 126 and 128 are transmitted and stored in the memory address storage 247 during the program mode after which the system, light or appliance controller 290 will respond to either or both of the transmitters 126 and 128. Any desired number of transmitters can be programmed to operate the system, light or appliance up to the available memory locations in the memory address storage 247.
Referring to
Preferably the self-contained relay 290 connects into a junction box 700 with threaded connectors allowing the relay control wires 605, 606 to enter through the hollow fitting into the junction box for wiring. The transformer 650, e.g., 120/277VAC to 24VDC, may be contained within the same enclosure as the relay, and the transformer wires into the junction box through the same connector. Alternately, the transformer 650 may be self-contained within its own separate enclosure and may further be connected by plug-in or threaded electrical connectors. The self-contained transformer 650 may be selectable from a wide variety of input AC or DC voltages and output DC voltages, and connectable in a like manner (by nippled or threaded connectors) to the relay 290 portion or to the junction box.
The operating voltage connection of the low voltage receiver 600 is connected via the wire(s) 655 (or may be directly connected) to the output of the Hi-Low voltage transformer which transforms the input line (AC or DC) voltage to a DC voltage under 60 VDC. The output of the low voltage receiver 600 (which is also a low voltage switching signal under 60 VDC) is connected via wire(s) 605, 606 to the input of the low voltage relay controller 660. The low voltage relay controller 660 generates the signal that switches the higher switched voltage, i.e., the same voltage that has been transformed, or separate high switched voltage. The relay 290 also isolates the DC receiver 600 from the switched voltage.
Referring to
Because the receiver 600 uses a low operating voltage to generate switching signals, it may be easily located for accessibility and maximum reception. That is to say, when a receiver is co-located with the switched relay as in
Referring to
The lighting fixture also preferably has a mounting area or socket 680 for attachment and retention of a low voltage receiver 600 as well as connection of the receiver to one of the outputs of the low voltage transformer 650. The low voltage receiver 650, which may be wired to the transformer 650 or plugged into a socket 680 is adapted to selectably control the lighting level of the lighting fixture to which it is attached. The low voltage receiver 600 is connected to a low voltage relay controller 660 which is connected to one or more relays 290 that control the lights within the fixture. The relay controller is preferably a 3-position controller that can vary the lighting level from “ALL ON”, “ALL OFF” and “50% ON”. Alternately, the receiver 600 may only be connected to one of the lights within the fixture. In this manner, the light fixture (and receiver) may be energized using the already wired conventional AC wall switch. A transmitter may be used to energize and de-energize the receiver, thereby turning on or off one of the two lights (or half of the total lights) within a lighting fixture.
In the embodiment of
In the embodiment of
The receiver is also capable of sending a variety of coded signal to the devices to which it is attached. For example a transmission of a “test” test code may disconnect lighting, sensor or alarm fixtures in order to test the battery backup for the emergency lighting, sensor or alarms. Another “test” code may perform a functional test of the alarm or sensors, and a “reset” code may deactivate an alarm that was set off for a test or otherwise (i.e., inadvertently by a power surge). Sending and “activate” code may engage a pump or fan motor for smoke and water clearance or it may switch motion sensors between an occupancy and a security/alarm mode. With the thermostat function of the receiver, the receiver may receive a temperature status to activate or deactivate heating and cooling devices. Obviously, On and Off control of all these devices is also a function that con be performed through the receiver. Also, the low voltage system extender increases reliability of reception of signals transmitted by the transmitter(s). Furthermore, the battery backup can provide power not only to emergency and health and safety devices in the building, but may also provide backup power to the receiver and/or system extender in order to provide backup power for activating and deactivating any device that the receiver is connected to.
In the preferred embodiment of the low voltage receiver with multiple outputs 685, the output wire(s) and receiver output connections for controlling the low power devices are color coded. For example, the fire/smoke alarm output port of the receiver may be colored red, and is adapted to receive red tipped wires from the smoke detector/fire alarm. The output ports and cooperating wire fittings adapted to be received therein may be specially shaped (i.e., circular, square, triangular, hexagonal) so that they can only be received in the appropriate port. Each of these ports is also specialized in that each port only has access to command functions within the receiver appropriate to that device. For example, the fire alarm port may only have test, reset and activate signals sent therefrom, but does not have an off signal which would remove the fire alarm from the power circuit. Again, such programming of command function outputs to specific output ports of the receiver is easily done on the PIC chip within the receiver. The output ports for connection to low power devices have fitting suitable for retention of the wires to the low voltage devices and may comprise spring loaded fittings, tensioned clips, friction fittings, push in and quick release fitting.
In the present invention a self-powered switch initiation system uses an electroactive element to develop an oscillating electrical signal. The accompanying circuitry is designed to work with that signal and generate a coded RF transmission. The system comprises one or more transmitters, receivers and repeaters that use that coded RF transmission to communicate specific electronic codes to each other to increase system range and reliability.
Referring to
The codes used by the transmitter and accepted for performing an action at the receiver or transceiver are preferably a 32-bit binary code comprising a unique (i.e., one of 224 to 230 combinations) transmitter identification code and a function code. These codes are programmed into the internal PIC/logic component during manufacture of the transmitter and are not changeable by the user of the device, although the user may have the ability to select one from a multiplicity of codes by using membrane switches or a selector device. The transmitters and transceivers are also programmed to send out a handshake code to establish the “language” and timing of signals among the transceivers and receivers.
Referring to FIGS. 16 and 22-23: The transmitters and transceivers use a “handshake” procedure to establish communications with other receivers and/or transceivers. The first code transmitted is the alternating portion of the handshake code which is a 4-20 bits of alternating ones (1) and zeros (0), each bit having defined a duration or pulsewidth. The number of bits as well as the pulsewidth defines the “language” that receivers and transceivers are programmed to accept before performing their desired function. Receivers and transceivers are programmed to respond only if they receive a certain number of those 1s and 0s at the defined pulswidth (say 12-15 out of 20). This handshake procedure also comprises a defined “dead time” after the number of alternating bits has been received. The typical handshake routine takes from 2-12 milliseconds. Upon receipt of the minimum number of bits in the alternating portion of the handshake, the receiver or transceiver is programmed to expect a time period having no transmission signal there, for example 6 to 8 cycles of the pulsewidth defined by the alternating portion. Upon receipt of an appropriate “handshake”, the receiver or transceiver will then listen to an incoming coded signal to determine whether receiver action or transceiver retransmission is necessary as defined by the internal programming of the receiver or transceiver.
In a system comprising two or more transceivers 460, the transceivers use a poling operation, which is programmed into each transceiver at manufacture, to assign channels or time slots for each transceiver. This operation prevents two transceivers from transmitting simultaneously or near simultaneously, thereby preventing out-of-phase transmission from interfering with each other. When a first transceiver is initially connected to a power source, the transceiver sends a signal corresponding to a setup mode, thereby “announcing” its presence in the system. This setup signal may correspond to the unique identification code of that transceiver, or a timing/handshake signal, or to a time slot/channel that that transceiver is assigned, or any combination of ID, handshake, timing or channel information. Alternately, and most preferably, rather than the “announcement code” being transmitted automatically upon connection to a power source, the transceivers have a setup mode which is activated by the user. The setup mode may be selected by moving a switch or pushing a button, for example.
Other transceivers 460 in the system are programmed to respond to this “announcement” signal with their own announcement code, containing at least the time slot to which the other transceivers are assigned. If the first transceiver does not receive a response from other transceivers in response to its “announcement” poling signal, that transceiver assigns itself the first time slot/channel. If a response is received from other transceivers, the first transceiver assigns itself the next sequential time slot, e.g., after receiving responses from two transceivers; the first transceiver assigns itself to the third time slot. Transceivers are typically programmed to have 4-16, and preferably 8 broadcast time slots/channels as this is sufficient to provide broad coverage within the transmission range of two or more repeaters.
As mentioned above, the codes generated by the transmitter and accepted for performing an action at the receiver or transceiver (after a handshake) are preferably a 32-bit binary code comprising a unique (i.e., one of 224 to 230 combinations) transmitter identification code and a function code. As shown in
Referring again to
The transmitters may be capable of developing one or more coded RF signals and the receivers likewise are capable of receiving one or more coded RF signals. The receivers have a memory therein for storing a number of codes, for example 5-50 code “slots”, and most preferably 30 codes. This permits the receivers to be “trainable” to accept coded RF signals from new or multiple transmitters and repeaters. The receiver is programmed to respond to codes from both transmitters and repeaters, and provide the same response action whether the trailing digit is a 0 from a transmitter or a trailing 1 from a repeater.
It is seen that the present invention allows a receiving system to respond to one of a plurality of transmitters which have different unique codes which can be stored in the receiver during a program mode. Each time the “program mode switch” 222 is moved to the program position, a different storage can be connected so that the new transmitter code would be stored in that address. After all of the address storage capacity has been used additional codes would erase an old code (i.e., FIFO) in the memory address storage before storing a new one.
Receivers are also programmed with a “dead time”, i.e., the repeater has a delay programmed into it so that it will only respond to one command within 1-2 seconds. This prevents the repeater from toggling multiple times in response to the reception of multiple transmitter and/or repeater codes within a certain time. Thus, if a receiver receives a code wherein the response is to toggle or change states, upon reception of that signal the receiver program initiates a delay period of 1-2 seconds wherein the receiver will not respond to any further received codes from transmitters or receivers.
A low voltage system extender 460 may also be used in conjunction with a low voltage receiver 600 as in
While in the preferred embodiment of the invention, the actuation means has been described as from mechanical to electric, it is within the scope of the invention to include batteries in the transmitter to power or supplement the power of the transmitter. For example, rechargeable batteries may be included in the transmitter circuitry and may be recharged through the electromechanical actuators. These rechargeable batteries may thus provide backup power to the transmitter.
This invention is safe because it eliminates the need for 120 VAC (220 VAC in Europe) lines to be run to each switch in the building. Instead the higher voltage overhead AC lines are only run to the appliances or lights, and they are actuated through the self-powered switching device and relay switch. The invention also saves on initial and renovation construction costs associated with cutting holes and running the electrical lines to/through each switch and within the walls. The invention is particularly useful in historic structures undergoing preservation, as the walls of the structure need not be destroyed and then rebuilt. The invention is also useful in concrete construction, such as structures using concrete slab and/or stucco construction and eliminate the need to have wiring on the surface of the walls and floors of these structures. Furthermore, the present invention has specific utility in commercial buildings where energy conservation has been mandated and energy savings (as well as government subsidies) can be realized, by allowing individual fixtures to have a 50% reduced lighting level. Further savings are realized because by having a low voltage power source available at every light fixture (through the transformer), other sensors and devices that use low voltage may be installed without having to have a dedicated or separate circuit for that device.
While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible, for example:
In addition to piezoelectric devices, the electroactive elements may comprise magnetostrictive or ferroelectric devices;
Rather than being arcuate in shape, the actuators may normally be flat and still be deformable;
Multiple high deformation piezoelectric actuators may be placed, stacked and/or bonded on top of each other;
Multiple piezoelectric actuators may be placed adjacent each other to form an array.
Larger or different shapes of THUNDER elements may also be used to generate higher impulses.
The piezoelectric elements may be flextensional actuators or direct mode piezoelectric actuators.
Other means for applying pressure to the actuator may be used including simple application of manual pressure, rollers, pressure plates, toggles, hinges, knobs, sliders, twisting mechanisms, release latches, spring loaded devices, foot pedals, game consoles, traffic activation and seat activated devices.
AC or DC power sources may be used rather than a deflected electroactive generator to power transmitters that communicate with the receivers and repeaters in the system.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US08/06679 | May 2008 | US | national |
This application claims priority to PCT Application Serial No. PCT/US08/06679, filed on May 27, 2008, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/931,572 filed May 24, 2007 entitled “Lighting Fixture with Low Voltage Transformer & Self-Powered Switching System.
