Abstract: An RF transmitter capable of transmitting a plurality of different codes at a plurality of different frequencies is set forth herein. The transmitter offers a new way of multiplexing inputs so that fewer controller I/O ports are needed to read or determine the state of a plurality of inputs. More particularly, the controller is capable of using one pin as both an input port and output port and determines the state of various inputs by detecting changes to the I/O pin. The multiple inputs connected to the controller pin are also connected to a pull down resistor and capacitor, and the controller can determine what state the inputs are in by detecting whether the pin input is at a logic high, low, or some state in between.

Abstract: A movable barrier operator (11) receives movement sensing signals from a sensor (13) and calculates corresponding speed of movement of a movable barrier. Such speed measurements lead to development of a median speed value over a monitoring window. The median speed value is used in a subsequent monitoring window to facilitate determining when speed of movement for the movable barrier has slowed in a way that likely corresponds to the movable barrier having encountered an obstacle.

Abstract: A movable barrier operator (11) receives movement sensing signals from a sensor (13) and calculates corresponding speed of movement of a movable barrier. Such speed measurements lead to development of a median speed value over a monitoring window. The median speed value is used in a subsequent monitoring window to facilitate determining when speed of movement for the movable barrier has slowed in a way that likely corresponds to the movable barrier having encountered an obstacle.

Abstract: A controller for controlling a motor and other functions in a commercial door or barrier operator is described. The controller includes a unique motor start circuit for starting an AC motor which employs two dual-pole-dual-throw (DPDT) relays for activating the start coil in combination with a single triac for activating the main coil of the motor, eliminating dv/dt sensitivity. A motor start control for a door or barrier operator includes a speed governor integrated onto the controller for detecting when to shut off AC power to the start coil in a single phase motor. The integrated speed governor uses an RPM sensor for detecting the speed of the operator's limit shaft coupled to software run by the processor. Switches for operating open, close, stop and learn functions are located on the controller to facilitate installation, maintenance and programming by a service provider at the door operator.

Abstract: A radio frequency transmitter for use in generating coded commands learned from received coded radio frequency signals. An transceiver circuit including a switching element and a tunable filter tuning element is coupled to a programmable controller, e.g, a microprocessor. The programmable controller operates the switching element of said transceiver circuit in either a first or a second mode for receiving or transmitting coded radio frequency signals, respectively via an antenna coupled to the tuning element. The switching element is operable in the first mode to demodulate received coded radio frequency signals, and the programmable controller learns the received coded radio frequency signals and stores coded commands in memory. In the second mode of operation, an oscillator is modulated by generated coded signals from the programmable controller using the stored coded commands from memory.

Abstract: A fire door opener and method of electronically controlling the door descent speed is described. The operator includes a DC brake solenoid coupled to an AC motor drive system with an inline gear reducer and an electronically controlled descent device with battery backup power. If the brake is disengaged, the door will drop by overcoming the internal inertia and friction in the inline gear reducer. Speed of descent is controlled electronically by measuring the descent speed of the fire door at its limit shaft and electrically modulating the brake engagement using the DC solenoid.