The presets used in the robot has three pins. The two pins that are together are the track pins. The pin that is separate from the track pins is the wiper. Connect one of the track pins to Vcc and the wiper to the Transistor as given in the circuit.
If you change the LDR to photodiode the robot will only be capable of line following and obstacle avoiding.
If you want to use photodiodes, build the main circuit board as given in the tutorial and then for the sensors, you will have to use a combination of IR LEDs and photodiodes.
For the circuit diagram of the sensor, visit http://www.triindia.co.in/resources/?p=52
Pratheek i need u explaination of the circuit please! According to the circuit the webpage u given, it shows that only one IR LED and one Photodiode.
1) Does it works only with this one or how many photodiode and IR LED needed for sensor? Is it also need 4 photodiode and 4 IR LED same as LDR sensor?
2) If yes use 4 IR LED and Photodiode, so how is the circuit looks like? Can u draw in eagle cad or other software to show the connection for sensor please?
3) Where should i connect the output pin for LM358N to? Is it wiper there?
4) According to the comment, is it the pot using 10k preset and the shape look like preset in the main board?
5) Can i dont use LED connect to 1k resistor on the output of LM358N
? because if i solder with it will look ugly on it.
THANKS PRATHEEK YOU ARE COOL MAN
!! I LOVE IT. PLEASE GUIDE ME MORE INFO!!