Manav Kataria's Blog

My LED Fader Lamp Attempt

I am trying to make a simple fading LED lamp that fades-in and out multiple colors. I have 3 LEDs Red, Green and Blue in the same package. I turn them on simultaneously.

Trying to mix colors:

The combination colors were not very clearly visible. I haven’t made a diffuser yet. OK. I just placed a white envelope on it. The red being the most intense overwhelms the r+b, r+g and r+g+b with its color. Blue + Green looks sexy but I think I better diffusion would make it prettier.

Normalized Intensities:

Reduced intensity of Red.

I still would love to know

  1. What is the best way (accurate method) to normalize the intensities and produce better colors
  2. Better ideas to diffuse light

Cheers!
Manav

/* Arduino Code*/

/*
Fading Triple Color RGB LED / PWM
Manav Kataria/1st April 2010

Using Stub: Fading; By Tom Igoe
This example shows how to fade an LED using the analogWrite() function.
http://arduino.cc/en/Tutorial/Fading
*/

/* Digital Pin Connections */
int redPin = 3;
int greenPin = 11;
int bluePin = 10;

int ledPin = redPin;

int colorSequenceTable[][3]={
{0xFF,0,0},    //Red
{0,0xFF,0},    //Green
{0,0,0xFF},    //Blue
{0xFF,0xFF,0},  //Yellow = Red + Green
{0xFF,0,0xFF},  //Magenta = Red + Blue
{0,0xFF,0xFF},  //Cyan = Blue + Green
{0xFF,0xFF,0xFF},  //White = Red + Blue + Green
{99,99,99}         //Terminate
};

void setup()  {
// nothing happens in setup
}

void loop()  {
mixrgb(100);
}

void mixrgb(int secs) {
for (int count = 0; colorSequenceTable[count][0] != 99; count++) {

// fade in
for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5) {
analogWrite(redPin, colorSequenceTable[count][0] & int(fadeValue/1.8));
analogWrite(greenPin, colorSequenceTable[count][1] & fadeValue);
analogWrite(bluePin, colorSequenceTable[count][2] & fadeValue);
delay(secs);
}
// fade out
for(int fadeValue = 255 ; fadeValue >= 0; fadeValue -=5) {
analogWrite(redPin, colorSequenceTable[count][0] & int(fadeValue/1.8));
analogWrite(greenPin, colorSequenceTable[count][1] & fadeValue);
analogWrite(bluePin, colorSequenceTable[count][2] & fadeValue);
delay(secs);

4 responses

  1. ABA

    I think .. the second color should begin.. BEFORE the first color is OFF completely..
    Secondly .. for yellow.. u may not need red in its full intensity.. so reduce it from 0xff to something less.. play around with those numbers..
    and reduce the delay..

    April 2, 2011 at 7:35 am

    • Will try that combo! Thank you for your feedback, Mr. ABA😉
      I agree that the red intensity needs to be reduced further.

      April 2, 2011 at 8:55 am

  2. Mohit

    Awesome!!!

    April 2, 2011 at 7:04 pm

    • Thanks Mohit!🙂

      April 4, 2011 at 5:22 am

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