Lab 3 :: Color Mixing with Potentiometers

Description

Three potentiometers are mapped independently to three LEDs to control their brightness (for mixing) and blinking rate. Fastest blinking occurs when a single LED is on, at its lowest brightness. Slowest blinking occurs when all three LEDs are on, at their maximum brightness.

Components Used

1- Arduino Uno

1- Breadboard

3- 220 Ω Resistor

3- Potentiometers

1- Green LED

1- Blue LED

1- Red LED

Cotton

 Code

/*

 * Each pot is mapped to one LED to control its brightness and blinking rate.

 * Modification of the following:

 * http://www.arduino.cc/en/Tutorial/AnalogInput

 * Adapted by Ajeeta Dhole on 2/17/2013.

 */

int greenPotPin = 2;   // select the input pin for the potentiometer controlling the green LED

int bluePotPin = 1;   // select the input pin for the potentiometer controlling the blue LED

int redPotPin = 0;   // select the input pin for the potentiometer controlling the red LED

int greenVal = 0;   // variable to store the value coming from pot controlling the green LED

int blueVal = 0;   // variable to store the value coming from pot controlling the blue LED

int redVal = 0;   // variable to store the value coming from pot controlling the red LED

int greenLEDPin = 9;   // select the pin for the green LED

int blueLEDPin = 10;  // select the pin for the blue LED

int redLEDPin = 11;  // select the pin for the red LED

void setup() {

   pinMode(greenLEDPin, OUTPUT);  // declare the greenLEDPin as an OUTPUT

   pinMode(blueLEDPin, OUTPUT);  // declare the blueLEDPin as an OUTPUT

   pinMode(redLEDPin, OUTPUT);  // declare the redLEDPin as an OUTPUT

}

void loop() {

   greenVal = (analogRead(greenPotPin)/4)*2/3; // read from pot controlling the green LED, and convert to 255 scale. scale brightness down to 2/3 of original to (approximately) match brightness of red LED.

   blueVal = (analogRead(bluePotPin)/4)*1/3; // read from pot controlling the blue LED, and convert to 255 scale. scale brightness down to 1/3 of original to (approximately) match brightness of red LED.

   redVal = analogRead(redPotPin)/4; // read from pot controlling the red LED, and convert to 255 scale

   analogWrite(blueLEDPin, blueVal); // dim LED proportional to the value from pot controlling the blue LED

   analogWrite(redLEDPin, redVal); // dim LED proportional to the value from pot controlling the red LED

   analogWrite(greenLEDPin, greenVal); // dim LED proportional to the value from pot controlling the green LED

   // delay is cumulative sum of values from the three pots.

   // fastest blinking occurs when a single LED is on at its lowest brightness.

   // slowest blinking occurs when all three LEDs are on at their maximum brightness.

   delay(blueVal);  // stop the program for some time

   delay(redVal);  // stop the program for some time

   delay(greenVal);  // stop the program for some time

   digitalWrite(blueLEDPin, 0);   // turn the blueLEDPin off

   digitalWrite(redLEDPin, 0);   // turn the redLEDPin off

   digitalWrite(greenLEDPin, 0);   // turn the greenLEDPin off

   delay(blueVal); // stop the program for some time

   delay(redVal);  // stop the program for some time

   delay(greenVal);  // stop the program for some time                

}