Arnov Sharma
Published © MIT

RGB PC Light Concept with XIAO RP2040

Made a portable RGB Light for one of my Project (the WoodFusion PC) which uses an WS2812 Matrix with XIAO RP2040 MCU

BeginnerFull instructions provided1 hour338

Things used in this project

Hardware components

Seeed XIAO RP2040
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Software apps and online services

Arduino IDE
Arduino IDE

Hand tools and fabrication machines

Seeed Studio Fusion PCB/PCBA
Seeed Studio Fusion PCB/PCBA

Story

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Schematics

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Code

TEST SKETCH 01

C/C++
#include <FastLED.h>

#define LED_PIN  D0

#define COLOR_ORDER GRB
#define CHIPSET     WS2811

#define BRIGHTNESS 128

// Helper functions for an two-dimensional XY matrix of pixels.
// Simple 2-D demo code is included as well.
//
//     XY(x,y) takes x and y coordinates and returns an LED index number,
//             for use like this:  leds[ XY(x,y) ] == CRGB::Red;
//             No error checking is performed on the ranges of x and y.
//
//     XYsafe(x,y) takes x and y coordinates and returns an LED index number,
//             for use like this:  leds[ XYsafe(x,y) ] == CRGB::Red;
//             Error checking IS performed on the ranges of x and y, and an
//             index of "-1" is returned.  Special instructions below
//             explain how to use this without having to do your own error
//             checking every time you use this function.  
//             This is a slightly more advanced technique, and 
//             it REQUIRES SPECIAL ADDITIONAL setup, described below.


// Params for width and height
const uint8_t kMatrixWidth = 16;
const uint8_t kMatrixHeight = 16;

// Param for different pixel layouts
const bool    kMatrixSerpentineLayout = true;
const bool    kMatrixVertical = false;

// Set 'kMatrixSerpentineLayout' to false if your pixels are 
// laid out all running the same way, like this:
//
//     0 >  1 >  2 >  3 >  4
//                         |
//     .----<----<----<----'
//     |
//     5 >  6 >  7 >  8 >  9
//                         |
//     .----<----<----<----'
//     |
//    10 > 11 > 12 > 13 > 14
//                         |
//     .----<----<----<----'
//     |
//    15 > 16 > 17 > 18 > 19
//
// Set 'kMatrixSerpentineLayout' to true if your pixels are 
// laid out back-and-forth, like this:
//
//     0 >  1 >  2 >  3 >  4
//                         |
//                         |
//     9 <  8 <  7 <  6 <  5
//     |
//     |
//    10 > 11 > 12 > 13 > 14
//                        |
//                        |
//    19 < 18 < 17 < 16 < 15
//
// Bonus vocabulary word: anything that goes one way 
// in one row, and then backwards in the next row, and so on
// is call "boustrophedon", meaning "as the ox plows."


// This function will return the right 'led index number' for 
// a given set of X and Y coordinates on your matrix.  
// IT DOES NOT CHECK THE COORDINATE BOUNDARIES.  
// That's up to you.  Don't pass it bogus values.
//
// Use the "XY" function like this:
//
//    for( uint8_t x = 0; x < kMatrixWidth; x++) {
//      for( uint8_t y = 0; y < kMatrixHeight; y++) {
//      
//        // Here's the x, y to 'led index' in action: 
//        leds[ XY( x, y) ] = CHSV( random8(), 255, 255);
//      
//      }
//    }
//
//
uint16_t XY( uint8_t x, uint8_t y)
{
  uint16_t i;
  
  if( kMatrixSerpentineLayout == false) {
    if (kMatrixVertical == false) {
      i = (y * kMatrixWidth) + x;
    } else {
      i = kMatrixHeight * (kMatrixWidth - (x+1))+y;
    }
  }

  if( kMatrixSerpentineLayout == true) {
    if (kMatrixVertical == false) {
      if( y & 0x01) {
        // Odd rows run backwards
        uint8_t reverseX = (kMatrixWidth - 1) - x;
        i = (y * kMatrixWidth) + reverseX;
      } else {
        // Even rows run forwards
        i = (y * kMatrixWidth) + x;
      }
    } else { // vertical positioning
      if ( x & 0x01) {
        i = kMatrixHeight * (kMatrixWidth - (x+1))+y;
      } else {
        i = kMatrixHeight * (kMatrixWidth - x) - (y+1);
      }
    }
  }
  
  return i;
}


// Once you've gotten the basics working (AND NOT UNTIL THEN!)
// here's a helpful technique that can be tricky to set up, but 
// then helps you avoid the needs for sprinkling array-bound-checking
// throughout your code.
//
// It requires a careful attention to get it set up correctly, but
// can potentially make your code smaller and faster.
//
// Suppose you have an 8 x 5 matrix of 40 LEDs.  Normally, you'd
// delcare your leds array like this:
//    CRGB leds[40];
// But instead of that, declare an LED buffer with one extra pixel in
// it, "leds_plus_safety_pixel".  Then declare "leds" as a pointer to
// that array, but starting with the 2nd element (id=1) of that array: 
//    CRGB leds_with_safety_pixel[41];
//    CRGB* const leds( leds_plus_safety_pixel + 1);
// Then you use the "leds" array as you normally would.
// Now "leds[0..N]" are aliases for "leds_plus_safety_pixel[1..(N+1)]",
// AND leds[-1] is now a legitimate and safe alias for leds_plus_safety_pixel[0].
// leds_plus_safety_pixel[0] aka leds[-1] is now your "safety pixel".
//
// Now instead of using the XY function above, use the one below, "XYsafe".
//
// If the X and Y values are 'in bounds', this function will return an index
// into the visible led array, same as "XY" does.
// HOWEVER -- and this is the trick -- if the X or Y values
// are out of bounds, this function will return an index of -1.
// And since leds[-1] is actually just an alias for leds_plus_safety_pixel[0],
// it's a totally safe and legal place to access.  And since the 'safety pixel'
// falls 'outside' the visible part of the LED array, anything you write 
// there is hidden from view automatically.
// Thus, this line of code is totally safe, regardless of the actual size of
// your matrix:
//    leds[ XYsafe( random8(), random8() ) ] = CHSV( random8(), 255, 255);
//
// The only catch here is that while this makes it safe to read from and
// write to 'any pixel', there's really only ONE 'safety pixel'.  No matter
// what out-of-bounds coordinates you write to, you'll really be writing to
// that one safety pixel.  And if you try to READ from the safety pixel,
// you'll read whatever was written there last, reglardless of what coordinates
// were supplied.

#define NUM_LEDS (kMatrixWidth * kMatrixHeight)
CRGB leds_plus_safety_pixel[ NUM_LEDS + 1];
CRGB* const leds( leds_plus_safety_pixel + 1);

uint16_t XYsafe( uint8_t x, uint8_t y)
{
  if( x >= kMatrixWidth) return -1;
  if( y >= kMatrixHeight) return -1;
  return XY(x,y);
}


// Demo that USES "XY" follows code below

void loop()
{
    uint32_t ms = millis();
    int32_t yHueDelta32 = ((int32_t)cos16( ms * (27/1) ) * (350 / kMatrixWidth));
    int32_t xHueDelta32 = ((int32_t)cos16( ms * (39/1) ) * (310 / kMatrixHeight));
    DrawOneFrame( ms / 65536, yHueDelta32 / 32768, xHueDelta32 / 32768);
    if( ms < 5000 ) {
      FastLED.setBrightness( scale8( BRIGHTNESS, (ms * 256) / 5000));
    } else {
      FastLED.setBrightness(BRIGHTNESS);
    }
    FastLED.show();
}

void DrawOneFrame( uint8_t startHue8, int8_t yHueDelta8, int8_t xHueDelta8)
{
  uint8_t lineStartHue = startHue8;
  for( uint8_t y = 0; y < kMatrixHeight; y++) {
    lineStartHue += yHueDelta8;
    uint8_t pixelHue = lineStartHue;      
    for( uint8_t x = 0; x < kMatrixWidth; x++) {
      pixelHue += xHueDelta8;
      leds[ XY(x, y)]  = CHSV( pixelHue, 255, 255);
    }
  }
}


void setup() {
  FastLED.addLeds<CHIPSET, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalSMD5050);
  FastLED.setBrightness( BRIGHTNESS );
}

Credits

Arnov Sharma
315 projects • 314 followers
Just your average MAKER

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