3.5 Photoresistor

Example 1:

Hardware Wiring

Photoresistor Example 1

Sketch

The code can be found at Examples_Arduino - sensor-kit-for-arduino - _015_PhotoResistor - _015_PhotoResistor.ino.

int sensorPin = 2;
int value = 0;
void setup() {
  pinMode(sensorPin, INPUT);
  Serial.begin(9600);
}
void loop() {
  value = analogRead(sensorPin);
  Serial.println(value, DEC);
  delay(50);
}

Example 2:

Hardware Wiring

Photoresistor Example 2

Sketch

The code can be found at Examples_Arduino - geek-workshop - studynotes - _005_Photoresistor - _005_Photoresistor.ino.

int photocellPin = 2; //define variable photocellsh=2, where we read the voltage
int ledPin = 12;  //define variable ledPin=12, led voltage output
int val = 0;    //define variable val


void setup() { 
  pinMode(ledPin, OUTPUT);  // set ledPin as mode OUTPUT
} 

void loop() { 
  val = analogRead(photocellPin);    //read analog signal from pin 2
  Serial.print(val);
  if(val<=512){      //512=2.5V, if more sensitive is expected, increase 512; otherwise, decrease 512
    digitalWrite(ledPin, HIGH); //if val < 512(2.5V), led is light up.
  }
  else{
    digitalWrite(ledPin, LOW);
  }
}