SENSOR: The sensor is a transducer type, it is used to sense or detect events or changes in physical quantities and gives a corresponding analog output.
TYPES OF SENSOR:
1. IR sensor.
2. proximity sensor.
3. Temperature sensor.
4. Pressure sensor.
5. Light sensor.
6. Fires sensor.
7. Vibrator sensor.
8. Gas sensor.
Here we discuss about IR sensors. IR sensor woks on the principle of emitting IR rays and receiving the reflected ray by the receiver called Photo Diode or photo Transistor.
IR Source Diode (Infrared LED) is used in forward bias condition.
IR Receiver (Photo Diode) or Photo Transistor is used in reverse bias condition.
VOLTAGE COMPARATOR CIRCUIT:
A comparator circuit compares 2 voltages either one (1) or zero (0) to indicate which is larger. it checks whether an input has reached some predetermined value Ref-voltage. The circuit IC amplifies the voltage difference between Vin anf Vref, and outputs the result Vout. If Vin greater than Vref then the voltage at Vout will rise to its positive saturation level.
If Vin is lower than Vref then the Vout will fall to its negative saturation level.
The combination IR and photo diode with an op-Amp IC LM358 circuits are used in the most of Line Follower Robots.