send signals over a relay logic line 102 to a relay logic module 104 connected to an alternating current motor 106 having a power take off shaft 108 coupled to the transmission 18 of the garage door operator a tachometer 110 is coupled to the shaft 108 and provides a tachometer signal on a tachometer line 112 to the microcontroller 84 the tachometer signal being indicative of the speed of rotation of the motor the power supply 72 includes a transformer 130 which receives alternating current on leads 132 and 134 from an external source of alternating current the transformer steps down the voltage to 24 volts and feeds 24 volts to a pair of capacitors 138 and 140 which provide a filtering function a 24 volt filtered dc potential is supplied on the line 76 to the relay logic 104 the potential is fed through a resistor 142 across a pair of filter capacitors 144 and 146 which are connected to a 5 volt voltage regulator 150 which supplies regulated 5 volt output voltage across a capacitor 152 and a zener diode 154 to the line 74 signals may be received by the controller at the antenna 32 and fed to the receiver 80 the receiver 80 includes a pair of inductors 170 and 172 and a pair of capacitors.