View Full Version : Photophobic robot

12-09-2009, 11:29 AM
Dear friends I need to build a photophobic robot. I have planned to use LDR for light sensing. The problem is i don't know to use what value of resitors and capacitors. Can anyone please give me a circuit for it and also if possible a tutorial on how to calculate the resistor and capacitor values.


12-14-2009, 01:33 PM
Hi.. just drive your motors directly with a transister like "187"... one for each motor.. For each transister connect an ldr between base and Vcc.. and once again for each transister connect a 100kPot between Gnd and base... Now emitter to gnd and collecter to -ve end of the motor... +ve end of the motor to Vcc.. Thats it!!!!
Adjust the pots such that motors start running only when some light falls on ldr...