Description

Controls RGB values with analog input from one potentiometer, and controls the brightness with analog input from another potentiometer.

Components Used

red LED

blue LED

green LED

(3) 220 resistors

(2) potentiometers

Arduino Code

//*
* Adapted from code by:
* Clay Shirky <clay.shirky@nyu.edu>
* Found at:
* http://www.arduino.cc/en/Tutorial/LEDCross-fadesWithPotentiometer
*/

// INPUT: Potentiometer should be connected to 5V and GND
int pot1Pin = 0;   // select the input pin for the potentiometer 1
int pot2Pin = 5;   // select the input pin for the potentiometer 2
float pot1Val = 0;   // variable to store the value coming from pot 1
float pot2Val = 0;   // variable to store the value coming from pot 2

// OUTPUT: Use digital pins 9-11, the Pulse-width Modulation (PWM) pins
// LED's cathodes should be connected to digital GND
int redPin = 9;   // Red LED,   connected to digital pin 9
int grnPin = 10;  // Green LED, connected to digital pin 10
int bluPin = 11;  // Blue LED,  connected to digital pin 11

// Program variables
int redVal = 0;   // Variables to store the values to send to the pins
int grnVal = 0;
int bluVal = 0;

void setup()
{
  pinMode(redPin, OUTPUT);   // sets the pins as output
  pinMode(grnPin, OUTPUT);  
  pinMode(bluPin, OUTPUT);
}

// Main program
void loop()
{
  pot1Val = analogRead(pot1Pin);   // read the value of pot 1 (for brightness), between 0 - 1024
  pot1Val = (pot1Val/1024);       // turn the value of pot 1 into a decimal
  pot2Val = analogRead(pot2Pin);   // read the value of pot 2 (for crossfades), between 0 - 1024
 

  if (pot2Val < 341)  // Lowest third of the potentiometer's range (0-340)
  {                 
    pot2Val = ((pot2Val * 3) / 4); // Normalize to 0-255

    redVal = (256 - pot2Val) * pot1Val;  // Red from full to off
    grnVal = pot2Val * pot1Val;        // Green from off to full
    bluVal = 0;             // Blue off
  }
 
 
  else if (pot2Val < 682) // Middle third of potentiometer's range (341-681)
  {
    pot2Val = ( (pot2Val-341) * 3) / 4; // Normalize to 0-255

    redVal = 0;            // Red off
    grnVal = (256 - pot2Val) * pot1Val; // Green from full to off
    bluVal = pot2Val * pot1Val;       // Blue from off to full
  }

 
  else  // Upper third of potentiometer"s range (682-1023)
  {
    pot2Val = ( (pot2Val-683) * 3) / 4; // Normalize to 0-255

    redVal = pot2Val * pot1Val;       // Red from off to full
    grnVal = 0;            // Green off
    bluVal = (256 - pot2Val) * pot1Val; // Blue from full to off
  }
  analogWrite(redPin, redVal);   // Write values to LED pins
  analogWrite(grnPin, grnVal);
  analogWrite(bluPin, bluVal); 

}

Image

Alana's Cloud Base (Light)

Alana's Cloud Base (Dark)