Arduino Experiment 6 - Photo Resistor Modify

Definition : By using photo resistor, we can change the resistor value and send different amount of voltage to the leds base on our light level ! We arrange lightlevel value and give different values of each led so they react different to light as you see.

Circuit Diagram

Components

•          1 x Photo Resistor
•          3 x Led ( Green, Yellow, Red)
•          3 x 330 Ω Resistor
•          Wires
•          Uno Board

Code

const int sensorPin = 0;

const int ledPin = 9;

int ledPin2 = 10;

int ledPin3 = 11;

// We'll also set up some global variables for the light level:

int lightLevel, high = 0, low = 1023;

void setup()

{

  // We'll set up the LED pin to be an output.

  // (We don't need to do anything special to use the analog input.)

  pinMode(ledPin, OUTPUT);

  pinMode(ledPin2, OUTPUT);

  pinMode(ledPin3, OUTPUT);

}

void loop()

{

  lightLevel = analogRead(sensorPin);

  manualTune();  // manually change the range from light to dark

  analogWrite(ledPin, lightLevel);

  analogWrite(ledPin2, lightLevel+1);

  analogWrite(ledPin3, lightLevel+100);

}

void manualTune()

{

 

  lightLevel = map(lightLevel, 0, 10, 0, 255);

  lightLevel = constrain(lightLevel, 0, 255);

}

void autoTune()

{

  if (lightLevel < low)

  {

    low = lightLevel;

  }

  if (lightLevel > high)

  {

    high = lightLevel;

  }

  lightLevel = map(lightLevel, low+30, high-30, 0, 255);

  lightLevel = constrain(lightLevel, 0, 255);

 

}

Video