XY Matrix
16x16 matrix (256 pixels) driven by an Arduino Nano, plastic diffuser, and faux TV.
Here’s the complete code for this effect; the whole program is well under a hundred lines, and the ‘effect’ itself is just twenty lines. Compiled code size is 3,756 bytes.
(This same code also pasted here XY Matrix sample (draft) - Pastebin.com )
A more fully commented version of this XY example code will be included in the v2.1 release of the FastLED library.
#include <FastLED.h>
#define LED_PIN 5
#define COLOR_ORDER GRB
#define CHIPSET WS2811
#define BRIGHTNESS 32
const uint8_t kMatrixWidth = 16;
const uint8_t kMatrixHeight = 16;
const bool kMatrixSerpentineLayout = true;
#define NUM_LEDS (kMatrixWidth * kMatrixHeight)
CRGB leds[NUM_LEDS];
void setup() {
FastLED.addLeds<CHIPSET, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS);
FastLED.setBrightness( BRIGHTNESS );
}
void loop()
{
uint32_t ms = millis();
int32_t yHueDelta32 = ((int32_t)cos16( ms * 27 ) * (350 / kMatrixWidth));
int32_t xHueDelta32 = ((int32_t)cos16( ms * 39 ) * (310 / kMatrixHeight));
DrawOneFrame( ms / 65536, yHueDelta32 / 32768, xHueDelta32 / 32768);
FastLED.show();
}
void DrawOneFrame( byte startHue8, int8_t yHueDelta8, int8_t xHueDelta8)
{
byte lineStartHue = startHue8;
for( byte y = 0; y < kMatrixHeight; y++) {
lineStartHue += yHueDelta8;
byte pixelHue = lineStartHue;
for( byte x = 0; x < kMatrixWidth; x++) {
pixelHue += xHueDelta8;
leds[ XY(x, y)] = CHSV( pixelHue, 255, 255);
}
}
}
// Helper function that translates from x, y into an index into the LED array
// Handles both ‘row order’ and ‘serpentine’ pixel layouts.
uint16_t XY( uint8_t x, uint8_t y)
{
uint16_t i;
if( kMatrixSerpentineLayout == false) {
i = (y * kMatrixWidth) + x;
} else {
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;
}
}
return i;
}
). This gives me a basic idea to work from.