Summary
This FM based remote control circuit used very popular encoder-decoder chips HT12E & HT12D. This ICs are widely used in many remot application. Here two 433Mhz Tx and Rx fm modules are used.
Transmitting section
As shown in figure-1 all the address lines A0-A7 (1-9 PINS) are connected to ground.This is done because address lines of both tx and rx should be same.
Receiver section
As the fig2 shows all the data line D0-D3 are connected to transistors q1-q4. At the collector pin of the relay and leds has been connected. The out put will be taken from the relay. Leds are used to identity which relay is on position. Here all the address lines are grounded as transmitting section.
