tri-color led wave

color-wave.js

var Board = require('../lib/firmata').Board;

valMin = 0;
valMax = 2 * (3.141592654);
valCur = 0.0;
step   = 0.1;
oscl_mult = (255/2);

leds = [ 9, 10, 11 ];

function getVals( offsetKey ) {
    return [
        oscl_mult * (Math.sin(valCur) + 1),
        oscl_mult * (Math.cos(valCur) + 1),
        oscl_mult * (Math.sin(valCur + 3.141592654) + 1)
    ];
}

var board = new Board('/dev/ttyUSB0', function() {
    console.log("init'd");
    for ( i = 0; i < leds.length; ++i ) {
        board.pinMode(leds[i], board.MODES.PWM );
    }
    setInterval(function(){
        if ( step < valMin || step > valMax ) {
            step = -step;
        }
        valCur += step;
        aoutvals = getVals(valCur);
        for ( i = 0; i < leds.length; ++i ) {
            board.analogWrite(leds[i], aoutvals[i]);
        }
    }, 50);
});