my dear friends i need help with a circuit i am making a remote controller for garage gate and lights i have used at89c51 at the transmitting and receiving ends but the problem is the transmission i dont heve any means of doing that do you you have any circuit which CAN TRANSMIT MY 8 BIT OR 4 BIT SIGNAL THROUGH fm OR AM AND THEN DEMODULATE THE SIGNAL AT THE RECEIVER AND THEN INPUT IT TO MY MICRO CONTROLLER PLZ GIVE ME THE SCHEMATICS DONT SEND CIRCUITS USING SINGLE CHIP MOD/DEMOD PLZ THANKYOU
Have a look at this simple 1-way data transmitter (schematics below) ..
It operates at 433MHz and uses pretty common components ..
For relaible transmission you will need to program microcontrollers to operate at rather low baud rates, say, 300bps, but for applicatins like yours even 300bps seems to be enough ..