Car Control - DC motor with relay

[blurr]

i want to make car control. i used DC motor with relay. instead using joystick, i use photodiode to send signal to my car so that car can move in forward or reverse direction. do u have any idea how to make circuit of photodiode as transmitter/receiver. and also i don't want to use PLC/PIC

 

[(*steve*)]

A photodiode can't be used as a transmitter. And even as a receiver, you'll require lots more circuitry (unless you want it to operate in complete darkness).

The simplest circuit would use a torch as the transmitter and a photodiode (or perhaps a phototransistor or CdS cell) as the receiver. The signal would be amplified and used to drive a relay.

Pointing the torch at the sinsor would cause the relay to pull in.

The relay could then be wired to normally apply power so the motor runs forward with the car in darkness and backward when in sufficient light (e.g. when the torch is shining on it).