Arduino LED manipulation sketch

readme.md

Download this to your Arduino libraries folder under a folder of the same name.

Something like: git clone https://gist.github.com/4751213.git SerialLED

SerialLED.ino

// LED manipulation code
// Borrows code from:
// * Adafruit's LED library: https://github.com/adafruit/LPD8806
// * Arduino example code for serial communication
// * astromaf's RGBLamp code: https://github.com/astromaf/MyRGBLamp

#include <LPD8806.h>
#include <SPI.h>

int dataPin  = 2;
int clockPin = 3;
int numLEDs = 32;

// First parameter is the number of LEDs in the strand.  The LED strips
// are 32 LEDs per meter but you can extend or cut the strip.  Next two
// parameters are SPI data and clock pins:
LPD8806 strip = LPD8806(numLEDs, dataPin, clockPin);

/*
  Serial RGB controller
 
 Reads a serial input string looking for three comma-separated
 integers with a newline at the end. Values should be between 
 0 and 255. The sketch uses those values to set the color 
 of an RGB LED attached to pins 9 - 11.
 
 The circuit:
 * Common-anode RGB LED cathodes attached to pins 9 - 11
 * LED anode connected to pin 13
 
 To turn on any given channel, set the pin LOW.  
 To turn off, set the pin HIGH. The higher the analogWrite level,
 the lower the brightness.
 
 created 29 Nov 2010
 by Tom Igoe
 
 This example code is in the public domain. 
 */

String inString = "";    // string to hold input
int currentColor = 0;
int led = 0;
int red, green, blue = 0;

void setup() {
  // Start up the LED strip
  strip.begin();

  // Update the strip, to start they are all 'off'
  strip.show();

  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  
  // send an intro:
  Serial.println("\n\nString to LED Address and then Int() RGB:");
  Serial.println();
}

void loop() {
  int inChar;

  // Read serial input:
  if (Serial.available() > 0) {
    inChar = Serial.read();
  }

  if (isDigit(inChar)) {
    // convert the incoming byte to a char 
    // and add it to the string:
    inString += (char)inChar; 
  }

  // if you get a comma, convert to a number,
  // set the appropriate color, and increment
  // the color counter:
  if (inChar == ',') {
    // do something different for each value of currentColor:
    switch (currentColor) {
      
    case 0:    // 0 = led
      led = inString.toInt() - 1;
      
      if (led < 0 || led >= numLEDs + 1) {
        led = 0;
      }
      // clear the string for new input:
      inString = ""; 
      break;

    case 1:    // 1 = red
      red = inString.toInt();
      // clear the string for new input:
      inString = ""; 
      break;
      
    case 2:    // 2 = green:
      green = inString.toInt();
      // clear the string for new input:
      inString = ""; 
      break;
    }
    currentColor++;
  }
  // if you get a newline, you know you've got
  // the last color, i.e. blue:
  if (inChar == '\n') {
    blue = inString.toInt();

    // print the color for the LED to change
    Serial.print("LED: ");
    Serial.print(led);
    Serial.print("Red: ");
    Serial.print(red);
    Serial.print(", Green: ");
    Serial.print(green);
    Serial.print(", Blue: ");
    Serial.println(blue);
        
    // Build the color from the passed numbers
    uint32_t color = strip.Color(red, green, blue);

    if (led == numLEDs) {
      for(int i = 0; i < numLEDs; i++ ) {
        strip.setPixelColor(i, color); // set one pixel
      }
    }
    else {
      // Set each pixel in the strip to the given color
      strip.setPixelColor(led, color); // set one pixel
    }
    
    strip.show();              // refresh strip display
       
    // clear the string for new input:
    inString = ""; 
    // reset the color counter:
    currentColor = 0;
  }
}