Patent Application
20100052846
1. Field of Invention
The present invention relates to a control system for garage door, and more particularly to a control system comprising a wall keyboard which outputs different potentials to represent outputting different instructions by operating different keys.
2. Description of Related Arts
In a garage door operator system, the user inputs instructions via an operation keyboard provided on a wall, wherein the electric circuit of the keyboard transfers states of the keys into electric signals of different values and then sends to a controller via one or more wires, and at last the controller controls a motor or other actuators to open or close the garage door, and turn on or turn off the working light.
The door operator ordinarily adopts the reactance method to transfer states of the keys into electric signals of different values, wherein the wall keyboard of the garage door operator is connected with the controller via one or more wires and sends key signals to the controller. The reactance-typed keyboard has each key connected with a reactor of different value, whose reactance is realized by capacitor. When a key is pressed, a driving circuit begins to charge the capacitor connected with the key, wherein the controller measures voltage change of the capacitor to make sure that whether a key is pressed. Afterward, because capacitors of different values have different discharge time, the controller measures the charge time and the discharge time of the capacitor to determine that which key is pressed. However, values of the capacitors of the above structure are easy to be changed under the influence of time and environmental factors such as temperature and humidity. The change of capacitor value causes the change of charge time and discharge time, and therefore causes the controller to misjudge the keys and the garage door to misact. In addition, capacitors have limited service life, and the price thereof is higher than resistors.
To overcome the above drawbacks existing in the prior art, the present invention provides a control system and method for a garage door, which improves the control signal transmission from keyboard to the controller thereof to fulfill the objects of increasing the operation liability and extending the service life of the keyboard.
Accordingly, the control system of the present invention comprises:
a motor;
a controller controlling operation of the motor; and
a keyboard for inputting an instruction into the controller, comprising a plurality of keys, a plurality of resistors corresponding to the keys, wherein each key is connected with one of the resistors in series to form a key mapping signal shunt, and the key mapping signal shunts are connected in parallel to form a group of key mapping signal shunts, a divider resistor for sharing voltage connected with the group of key mapping signal shunts in series to form a series circuit, wherein a driving voltage is applied on the series circuit, and a voltage signal output circuit for transmitting a voltage on the group of key mapping signal shunts to the controller.
Therefore, when the keyboard is idle, each key is disconnected to cut every key mapping signal shunt, thereby the voltage output by the voltage signal output circuit is equal to the provided driving voltage; when a key is pressed, the key mapping signal shunt where the key locates is connected and forms a series circuit with the divider resistor. Because the resistors respectively connected with the keys in series are different, the voltage on the key mapping signal shunt is different when different key is pressed. The voltage on the key mapping signal shunt is transmitted to the controller via the voltage signal output circuit for the controller to determine the corresponding key by the voltage on the key mapping signal shunt, so as to take correct action to operate the garage door and a working light. The present invention adopts resistors of different values to distinguish different keys. As comparing to capacitors, resistors have more stable parameters, are less affected by factors such as environmental temperature and humidity, and therefore reduce misjudgment of keys; besides, resistors have longer service life, low cost and low failure rate; and the keyboard has simple circuit structure, and needs only two wires connected with the driving circuit of the keyboard of the controller, and therefore is convenient to connect, simple and reliable.
To further perfect and supplement the above embodiment, the present invention have the following features or combination of the features.
The group of key mapping signal shunts has a first end connected with the divider resistor in series, and a second end grounded. The divider resistor has a first end connected with the group of key mapping signal shunts, and a second end connected and applied with a signal of the driving voltage. The voltage signal output circuit extends to the controller from a connection point between the group of key mapping signal shunts and the divider resistor.
The keyboard further comprises a key locking circuit. The key locking circuit is connected to a locking signal output terminal of the controller. When the controller sends a locking signal, the key locking circuit keeps the voltage output by the group of key mapping signal shunts unchanged, and therefore any key is disenable. When the controller sending a unlocking signal, the voltage output by the group of key mapping signal shunts is changed by the keys.
The key locking circuit comprises a NPN transistor which has a collector and a grounded emitter connected with the group of key mapping signal shunts in parallel. The locking signal output terminal of the controller is grounded via a tandem connected current limit resistor and pull-down resistor. The NPN transistor has a base connected with a node between the current limit resistor and the pull-down resistor. In an unlocking manner, the locking signal output terminal outputs a low electric level signal, such that the base of the transistor has no current, and the transistor is off, when the voltage output by the group of key mapping signal shunts is responded to the keys. In a locking manner, the locking signal output terminal outputs a high electric level signal, such that the current limit resistor and the pull-down resistor have current passing through to provide current to the base, and the transistor is on, in such a manner that the group of key mapping signal shunts is in short circuit, and when any key is pressed, the voltage output by the group of key mapping signal shunts approximates zero, and the controller judges to take no action.
The key locking circuit further comprises a diode provided between the locking signal output terminal and the current limit resistor to prevent adverse current to the controller.
The keyboard further comprises an indicating circuit connected with the group of key mapping signal shunts in parallel and comprising a LED and a LED current limit resistor which are connected in series. When the key is pressed effectively, the LED indicates a corresponding state.
The keyboard comprises five key mapping signal shunts respectively corresponding to keys of switching, travel learning, remote control learning, remote control locking, and light controlling, so as to instruct the controller to take actions of opening or closing the garage door, setting an upper limit position and a lower limit position of the garage door, learning a remote controller, locking the remote controller, and controlling an indicating and illuminating lamp.
The control system for the garage door further comprises an infrared alarm means for monitoring if there is an obstruction under the garage door.
The control system for the garage door further comprises a remote controller for controlling the garage door remotely when it is not convenient to operate the keyboard.
The control system for the garage door further comprises a motion detecting device for detecting a position, a speed and other information of the garage door.
The wall keyboard with the improvement by present invention has the advantages of stable operation, less misaction, lower cost, extended service life, convenient use and safety.
These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.
Referring to
Referring to
An electric circuit of the keyboard 101 is illustrated in
A key locking circuit comprises a NPN transistor 413, a diode 420, a current limit resistor 404 and a pull-down resistor 412. The single chip 400 has a RC2 pin 402 as a locking signal output terminal, which is connected with the diode 420, the current limit resistor 404, the pull-down resistor 412, and then the ground. A node between the current limit resistor 404 and the pull-down resistor 412 is connected to a base of the NPN transistor 413. The current limit resistor 404, the pull-down resistor 412, and the diode 420 are connected with the base, and an emitter and a collector of the NPN transistor 413 are connected in parallel beside the group of key mapping signal shunts.
In working, the single chip 400 scans the keys of the keyboard periodically. When scanning the keyboard, the RC2 pin 402 is first set to low, and at that time the NPN transistor 413 is off. The pressed key is connected with the corresponding resistor and the divider resistor 405 in series to share the driving voltage. When different key is pressed, the key mapping signal resistor connected in series is different, and therefore a resistance produced between two signal wires 421 and 422 of the keyboard is different. When a voltage of 5V is applied on the two signal wires 421 and 422 via the divider resistor 405, an electric level value produced on the signal wire 421 is different. By utilizing an A/D module function of the single chip 400, different electric level values are converted into different digital signals. The single chip 400 detects the pressed key of the keyboard on the wall by reading the digital signals.
If the RC2 pin 402 is set high, the NPN transistor 413 is on, an electric level value of the signal wire 421 of the keyboard on the wall approximates zero, when the keyboard is locked, any key input is useless.
One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.
It will thus be seen that the objects of the present invention have been fully and effectively accomplished. Its embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200820163397.6 | Sep 2008 | CN | national |
