Tangible User Interfaces - Fall 2011

Description

Expand on RGB LED dimmer code by allowing for advanced serial communication, and add a diffuser to blend RGB LED colors. My code allows you to control each LED in 20% brightness increments, with R using "1-6", G using "q-y", and B using "a-h". I did this because as a designer, I'm used to picking colors by hue, saturation, and brightness (HSB), but specify the colors in RGB for a developer to use. This interface allows for a way to understand how RGB color mixing works. The diffuser I used was a plastic bottle stopper. I found that for better color mixing, the important thing is to point all three LEDs so they point to the same spot.

Components

• 3 x 330Ω
• R, G, & B LEDs
• bottle stopper diffuser

Arduino Code

// Ian Leighton
// TUI 2011-09-13
// Homework: Serial RGB LED Keyboard Dimmer

/*
Dims RGB LEDs in 20% increments using
1-6 Red
q-y Green
a-h Blue
*/

int colorP;
int bright;
char in;
int brightness;

#define redPin11   // Red LED,   connected to digital pin 9
#define greenPin 10  // Green LED, connected to digital pin 10
#define bluePin 9  // Blue LED,  connected to digital pin 11

void setup() {
  pinMode(redPin,   OUTPUT);   // sets the pins as output
  pinMode(greenPin, OUTPUT);   
  pinMode(bluePin,  OUTPUT);
  Serial.begin(9600);
  analogWrite(redPin,   0);   // set them all to mid brightness
  analogWrite(greenPin, 0);   // set them all to mid brightness
  analogWrite(bluePin,  0);   // set them all to mid brightness
  Serial.println("enter a color value using the first three row of the keyboard (e.g. '3rk') :");  
}

void loop () {
in = Serial.read();
if (in != -1) {    
    // check color
    if(in == '1' || in=='2' || in=='3' || in=='4' || in=='5' || in=='6') {
      colorP = redPin; 
      Serial.print("R = "); }
    if(in=='q' || in=='w' || in=='e' || in=='r' || in=='t' || in=='y') {
      colorP = greenPin;
      Serial.print("G = "); }
    if(in=='a' || in=='s' || in=='d' || in=='f' || in=='g' || in=='h') {
      colorP = bluePin;
      Serial.print("B = "); }
    
    // check brightness
    brightness = readBrightness(in);
    analogWrite(colorP,brightness);
    Serial.println(brightness, DEC);
  }
}

// read and return the brightness from character input
int readBrightness (char in) {
  if (in=='1' || in=='q' || in=='a'){
    bright = 0; }
  if (in=='2' || in=='w' || in=='s'){
    bright = 51; }
  if (in=='3' || in=='e' || in=='d'){
    bright = 102; }
  if (in=='4' || in=='r' || in=='f'){
    bright = 153; }
  if (in=='5' || in=='t' || in=='g'){
    bright = 204; }
  if (in=='6' || in=='y' || in=='h'){
    bright = 255; }
return bright;
}