ANALOG PROXIMITY SENSOR FOR ARDUINO



In a previous section I discussed about digital proximity sensor using opamp.But for high performance line follower robote we need analog sensor for better calculation on program and it will help to build a high performance line follower robote.
It's so simple that only need few components. and the rest of the part is done by microcontroller(generally Arduino) and the program .
COMPONENTS
1)Photo diode
2)IR led
3)R1-1k ohm
4)R2-150k ohm
Here the photo diode is connecting in reverse baise.ir led in forward bias with resistance 1k to reduce the voltage .and the photo diode is connected to ground through 150K resister .the output is taken between R2 and photo diode .The output voltage can adjust by changing the R2 .Here we put 150k ohm to get maximum output voltage variation for white and black surface .By adjusting the R2 we can change the output voltage level. by no.of experiments I found 150 kohm can provide maximum output voltage for this circuit.The output of the circuit can connect to analog input of the microcontroller.