Help needed for programming Rainbowduino's - London UK

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1

Hello,

I would like some help with programming a Rainbowduino to randomly fade LEDs in and out.
Essentially I will be using the Rainbowduino to power 192 LEDs individually as suppose to 64 RGB LEDs.

Someone had previously achieved this for me by tweaking a random demo sketch, available in the Rainbowduino library. This allowed many LEDs to fade in and out simultaneously at random intervals over a long loop cycle making it impossible to figure out the cycles.

This is all a grey area for me and I was wondering if someone would be kind enough to advise me on which demo they may have used and how one would tweak it to control the brightness etc.

Any help and advise would be much appreciated.

Thanks
Alex

2

Hmm. So, you have a rainbowduino, you have a bunch of LEDs, you have worked out how to connect all the LEDs to the board and now it's a matter of writing a nice sketch to run them - is that right?

Or do you need help with mutiplexing the LEDs? Working out what wires go where?

I'm finding three "rainbowduino" products:

Ah - this appears to be the relevant one: Rainbowduino v3.0 | Seeed Studio Wiki . " It can drive an 8x8 RGB Led Matrix or a 4x4x4 RGB LED Cube in common Anode mode. " = seems to be the one you are talking about. Fine. Now … where's the API?

GitHub - unwiredben/Rainbowduino-v3: Support library from Seeed Studio for Rainbowduino v3 board, as used in their Rainbow Cube this looks like the API. I shall snarf it …

Ok, there's some sample code:

    for(x=0;x<8;x++)
    {
     for(y=0;y<8;y++)
      {
      Rb.setPixelXY(x,y,random(0xFF),random(0xFF),random(0xFF)); //uses R, G and B bytes
      }
    }

Cooking. Now, you need a function "setSInglePixel" which takes a pixel 0-192 and a value 0-255. Unfotunately, you need to preserve the other two colours of the pixel you are talking to, and there's no 'getPixel' function. No matter - we shall have to do it the hard way:

uint32_t pixels[64];

void setPixel(int pix, byte v) {
  int pp = pix/3;  // which 'led'
  int rgb = pix % 3; // r, g, or b in that 'led'

  uint32_t vv = (uint32_t) v << (8 * rgb);  // righ-shift the target value;
  uint32_t mask = 0xFF << (8 * rgb); // make a 8-bit mask;
  vv |= pixels[pp] & ~mask; // preserve the other r/g/b values
  pixels[pp] = vv; // save the result
  Rb.setPixelXY(pp >> 8, pp % 8, vv); // explain this to the rainbowduino
  }

Now, you want to "randomly fade LEDs in and out". Not quite sure what that means.

int led_being_faded = 0;
byte current_value = 1;

void loop() {
  delay(10);

  if(current_value == 255) {
    current_value = 254;
  }
  else if(current_value == 0) {
    current_value = 1;
    led_being_faded = random(192);
  }
  else if(current_value & 1)  {
    current_value += 2;
  }
  else {
    current_value -= 2;
  }

  setPixel(led_being_faded, current_value);
}

If that's not what you want, you may have to get a little more specific.