Abstract: A remote control system for opening and closing a barrier, such as a garage door, includes an RF receiver and a plurality of RF transmitters. The transmitters and receiver include circuitry programmed to provide transmission of encrypted code signals each time the transmitters are used and employing a code hopping method which prevents unauthorized signal interception or code “grabbing”. The system is operated in a code learning mode for the receiver by momentarily actuating a receiver learn mode button for receiving each transmitter identification code and a secret decryption key for that transmitter with the system automatically returning to the operate mode. Each transmitter identification and secret key code signal is automatically and randomly stored in an available and unused memory in the receiver circuitry.

Abstract: A remote control system for opening and closing a barrier, such as a garage door, includes an RF receiver and a plurality of RF transmitters. The transmitters and receiver include circuitry programmed to provide transmission of encrypted code signals each time the transmitters are used and employing a code hopping method which prevents unauthorized signal interception or code “grabbing”. The system is operated in a code learning mode for the receiver by momentarily actuating a receiver learn mode button for receiving each transmitter identification code and a secret decryption key for that transmitter with the system automatically returning to the operate mode. Each transmitter identification and secret key code signal is automatically and randomly stored in an available and unused memory in the receiver circuitry.

Abstract: A door operator system for an upward acting sectional or one piece (California-type) garage door includes a DC variable speed motor directly connected to a drive mechanism for moving the door between open and closed positions. A motor control circuit includes circuit components for reversing the direction of rotation of the motor and for delivering a pulse width modulated voltage signal to the motor to control motor speed. A current sensor including a split core transformer and a Hall effect sensor detects motor current and provides a signal to a microcontroller for stopping the motor or stopping and reversing the motor if the motor current reaches a preset limit which is user settable by potentiometers connected to the microcontroller. Magnetic position limit switches and an obstruction detector are operably connected to the microcontroller to provide input signals indicating the state of the door and the control circuit.

Abstract: A remote control system for opening and closing a barrier, such as a garage door, includes an RF receiver and a plurality of RF transmitters. The transmitters and receiver include circuitry programmed to provide transmission of encrypted code signals each time the transmitters are used and employing a code hopping method which prevents unauthorized signal interception or code "grabbing". The system is operated in a code learning mode for the receiver by momentarily actuating a receiver learn mode button for receiving each transmitter identification code and a secret decryption key for that transmitter with the system automatically returning to the operate mode. Each transmitter identification and secret key code signal is automatically and randomly stored in an available and unused memory in the receiver circuitry.

Abstract: A circuit which gives a continuous voltage output indication of whether a contact is open or closed. The circuit senses the voltage across the contact to detect whether the contact is open or closed. When there is a significant voltage, the circuit indicates that the contact is open. When the voltage is negligible, the circuit indicates that the contact is closed. Alternatively, the current through the contact can be sensed to provide an indication of whether the contact is conducting or not. The circuit can be used to indicate the welding close of a relay contact in which case power to the load can be turned off or the contact can be opened by other than normal corrective actions. One application is to discontinue closing movement of a garage door when the motor relay switch does not open as desired, but there are innumerable other applications.

Abstract: A control unit remotely operates several different functions of a gas fireplace. The functions include ignition of a fire, control of flame height, blower control, and damper control. An RF or IR transmitter has several different switches corresponding to desired operations to be performed. Each switch or combination of switches sends different coded signals to a receiver in the control unit. The control unit operates a gas valve and an ignitor to start the fire in response to a start signal. The gas valve is further controlled to vary the height of the flame or extinguish the flame in response to corresponding signals. The blower, damper and other functions can be controlled in response to other signals.

Abstract: The light beam in an obstruction detector is coded into packets of pulses by a transmitter according to a code generated only by the transmitter. When the light beam is received, the receiver recovers the code signal and supplies it to a code detection circuit. In one preferred embodiment, to detect the code, the code detection circuit supplies the code signal and a delayed version of the code signal to an "exclusive or" gate. In another embodiment, a frequency detection circuit determines whether the code signal detected by the receiver is within a predetermined permissible range. If the code is not present, the door operator system reverses the door if it is closing, and prevents the door from closing if it already is in the up position, or if it is opening. The door operator system will operate in this way not only in response to obstructions, but also, in response to errors and malfunctions in the wiring to the transmitter and receiver, and in the transmitter and receiver themselves.

Abstract: A door operation control system has a door opening for moving a door between open and closed positions. A door operator control circuit selectively operates the drive means to move the door between the open and closed positions. An obstruction detection device detects whether there is an obstruction in the path of the door between the open and closed positions and generates a signal in response thereto. The obstruction detection device is connected to the control circuit by wiring to permit operation of the door opener in the absence of a signal from the obstruction detection device and to prevent certain operations of the door opener in the presence of a signal from the obstruction detection device. An error detection circuit detects faults or errors in the wiring and generates a signal to prevent certain operations of the door operator when the faults or errors are detected.

Abstract: A safety system is disclosed for universal attachment to existing garage door openers. A transmitter of infrared energy transmits a beam laterally of the door opening to detect any obstruction to door closing movement. A safety control circuit is adapted for connection to the main control circuit of the existing garage door opener, the existing push button switch is disconnected from the main control circuit and connected to the new safety control circuit, a flexible cable or cord is connected for actual movement in accordance with movement of the door and is connected to the safety control circuit at a reel on which the cord is wound, and the safety control circuit determines if there is actual door movement and actual door closing movement, as well as being responsive to an obstruction to door closing movement to apply a signal to stop the door and then apply another signal to start the door in its opening movement.