Patent Application
20080152354
Structured wiring has become commonplace in residential and industrial buildings. Structured wiring as used herein means pre-wiring and centralizing wiring such that changes, additions to and troubleshooting of the electronic infrastructure of the building will be greatly simplified. Wall switch boxes generally contain either high voltage wiring or low voltage wiring, but according to the National Electrical Code, they cannot ordinarily simultaneously contain both. Wall box dimmers for example can be interconnected using normal high voltage (115 v) house wiring, but cannot be connected together using CAT-5 communications cable because the CAT-5 cable cannot be placed inside the wall switch box. Radio frequency receivers and transmitters can be utilized to interconnect the units, but are subject to range limitations, frequency interference, and many other potential reliability issues. Centralized dimming systems are available, but they require a completely different wiring scheme from conventional wiring.
It would be beneficial for condominium or other multi-unit developers to be able to pre-wire wall switch boxes using CAT-5 communications cable at the high voltage switch box locations. This is not possible because of the NEC rule barring low and high voltage circuits entering the same wall box. The present invention provides a method and apparatus to provide low voltage control of high voltage equipment without violating any rules or safety codes. It allows pre-wiring of CAT-5 cable at all high voltage locations so that control signals from a centralized controller can be brought into that box without the need for an electrical conductor. Thus, the cost of the equipment can be passed on to the end-user as an optional feature without the need for the builder/developer to pay for the total equipment cost.
The principal object of this invention is to eliminate the problem associated with using high and low voltage in the same wall box in order to control the fixtures, appliances or equipment associated with the wall box. Another object of the invention is to provide the capability of having the control system completely hard-wired to provide a system that is inherently extremely reliable. Yet another object of the invention is to improve the resistance of household control circuits to lightning and static discharge.
A structure is pre-wired by running a standard communications cable, for example CAT-5 or equivalent cable from a central location to each location which may be later controlled. The wire is secured to the outside of the “rough-in” box by one or more attachment means. A length of the wire is then pulled inside the box so that a “smart bubble” may be later installed at that point in the cable. When the structure is finished, the owner may elect to place a device such as a wall box dimmer, fan speed controller, audio system controller, intercom, security panel, or other device at each location, or, he/she may decide to simply push the low voltage wire back out of the box into the wall and install a conventional switch/device. If a device controller is to be installed, then an electrical to optical converter or smart bubble is installed externally to the wall box and a non-conductive optical fiber is connected between the smart bubble and an optical to electrical converter inside the box connected to a control device for the structural wiring for the wall box.
The embodiments of the present invention are depicted in the appended drawings which form a portion of this disclosure and wherein:
a is a perspective view of a door with optical fibers passing through the door.
Referring to the drawings for a clearer understanding of the invention it may be seen from
At trim out time (Europeans call it the “final fixing”) a decision is made for each wall box 16 whether to trim it out with controlled or conventional devices. If conventional devices are to be installed at any given wall box location, then the CAT-5 wire is not needed. It is simply pushed back out into the wall and a door 20 covering the aperture in the wall box is installed.
If the owner wishes to be able to control the high voltage device located in the wall box 16 then it will be necessary to “trim out” the cable 11 to add a high voltage device. To trim out cable 11 at a wall box 16, cable loop 18 inside wall box 16 can be cut creating two “free” ends 21 and 22. The free ends 21, 22 are each fitted with a RJ-45 CAT-5 cable plug 23. The cable plug 23 fits into a CAT-5 cable socket 24 on a “smart bubble” 26. The “smart bubble includes a circuit board 27 connected to two RJ-45 CAT-5 cable sockets 24 and one or more fiber optic cable connectors 28 associated with an optical transmitter 31 and receiver 34 included on circuit board 27. The basic optical transmitter converts electrical input signals from MCU 12 into modulated light for transmission over an optical fiber. Depending on the nature of this signal, the resulting modulated light may be turned on and off corresponding to a digital signal or may be linearly varied in intensity between two predetermined levels. Typically a light emitting diode or laser diode is used as the light source in an optical transmitter. Fiber optic connectors 28 are connected to optical fiber 29. When the free ends 21, 22 of cable 11 are connected to the smart bubble 26, the bubble 26 and the cable ends 21, 22 are pushed through the aperture 16 with the optical fiber 29 connected to smart bubble 26 extending through an aperture into the wall box. The smart bubble is powered by the low voltage carried by the CAT-5 cable 11 and regulated by voltage regulator 43 on circuit board 27.
Alternatively, as shown in
The optical fiber 29 attaches to the controlled equipment 32, which may be an on/off switch, a three position switch, a dimmer, or any other such equipment. Controlled equipment 32 has an associated control circuit 36 mounted inside wall box 16. As seen in
The present invention thus represents a significant improvement over the invention described in U.S. Pat. No. 6,297,724 which described the use of opto-couplers which did not provide true electrical isolation between a low voltage control circuit and the AC circuit powering the controlled equipment. It should be noted that hard wired systems, including the one shown in the '724 patent are somewhat prone to lightning damage because of electrically conductive connections between devices. In opto-couplers as described in the '724 patent the physical and electrical separation between components fails to protect against higher voltage due to the close proximity of the components. In other words, the '724 device has both low and high voltage on the same board and is not acceptable for use in the applications contemplated by the present invention. The present system isolates all units from each other by means of electrically non-conductive optical fiber. It also eliminates the possibility of a low voltage copper wire becoming high-voltage live by coming into contact with a live AC circuit.
The last location on the low voltage cable 11 must have a “terminator plug” 36 installed in the open end of the “smart bubble” 26. The “terminator plug” consists of a circuit board, an RJ-45 plug, and other electronic components which are necessary for proper reliable transmission of data down the cable.
During installation, cable 11 should (but not absolutely necessary) be looped all the way back to the origination point if possible. By doing so, even if the cable is accidentally broken or cut at any point in the middle, a complete connection can be made to all the devices by starting at one end and placing a terminator plug 36 at the last good cable location. Alternatively, as shown in
In one embodiment of the system, all data connections including the connection from the MCU 12 to the cable 11 are made using optic fiber as shown in
It should also be noted that in a wall box 16 having multiple switches or control devices, each control circuit can be connected to a separate smart bubble by optical fiber, however, this is not necessary for isolation of the control cable 11 in as much a single optical fiber connection can carry the control signals for each switch. In this embodiment, the optical fiber is connected to a control circuit 36 associated with one of the controlled equipment 31 in the wall box and the signals to the other controlled equipment in the box, if any, can be transmitted over low voltage electrical connections to their associated control circuits 36. It will be appreciated that each switch, dimmer or other device will be uniquely identified in the system such that the MCU can selectively communicate with each such unit. Thus, the circuitry on each smart bubble may have resident logic components which can discriminate as to which digital signals sent by the MCU are intended for the equipment that is optically connected to that smart bubble and which will activate the optical transmitter only when it identifies a signal intended for the associated equipment. Alternatively, the circuitry inside the wall box includes resident logic which can accept or pass the signal to other devices inside the wall box, and in such circumstances the smart bubble does not need the resident logic to determine which signals to pass. In some instances, the smart bubble 26 and the low voltage control circuit inside the wall box will have both optical transmitters and receivers such that reply signals can be sent from the controlled equipment to the MCU 12 as needed. In the foregoing example, a wall box 16 may include three control elements such as two position switches controlling different lighting elements. Each switch may have an associated control circuit associated therewith. In the present invention each control circuit 36 would be uniquely digitally identified such that the MCU 12 could send control signals to the circuit to control the operation of the switch. The smart bubble 26 adjacent wall box 16 would have fiber optic connection to one of the control circuits 36 a inside the box, and that control circuit would have low voltage connection to each other control circuit such that the digital signals transmitted optically to the one control circuit could be relayed to the other control circuits 36b and c. Since each circuit is digitally identified, the logic on each circuit is responsive only to signals including its digital identifier. Likewise the smart bubble may be configured to optically pass the digital information only to the control circuits 36 with which it is in optical communication, passing non-associated digital commands along the communications cable 11 in uninterrupted fashion.
In another embodiment of the invention, shown in
While the present invention has been described with reference to multiple embodiments, it is not so limited and the embodiments described are for purposes of illustration, it being understood that the invention is limited only by the scope of the appended claims.
