Arduino source code: SK6812 LED test exerciser

ArrayTest-RGBW.ino

// SK6812 RGBW LED array exerciser
// Ed Nisley - KE4ANU - February 2017

#include <Adafruit_NeoPixel.h>

//----------
// Pin assignments

const byte PIN_NEO = A3;			// DO - data out to first Neopixel

const byte PIN_HEARTBEAT = 13;		// DO - Arduino LED

//----------
// Constants

#define UPDATEINTERVAL 20ul
const unsigned long UpdateMS = UPDATEINTERVAL - 1ul;		// update LEDs only this many ms apart minus loop() overhead

// number of steps per cycle, before applying prime factors
#define RESOLUTION 100

// phase difference between LEDs for slowest color
#define BASEPHASE (PI/16.0)

// LEDs in each row
#define NUMCOLS 5

// number of rows
#define NUMROWS 5

#define NUMPIXELS (NUMCOLS * NUMROWS)

#define PINDEX(row,col) (row*NUMCOLS + col)

//----------
// Globals

// instantiate the Neopixel buffer array

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUMPIXELS, PIN_NEO, NEO_GRBW + NEO_KHZ800);

uint32_t FullWhite = strip.Color(255,255,255,255);
uint32_t FullOff = strip.Color(0,0,0,0);

struct pixcolor_t {
	byte Prime;
	unsigned int NumSteps;
	unsigned int Step;
	float StepSize;
	float TubePhase;
	byte MaxPWM;
};

// colors in each LED
enum pixcolors {RED, GREEN, BLUE, WHITE, PIXELSIZE};

struct pixcolor_t Pixels[PIXELSIZE];						// all the data for each pixel color intensity

unsigned long MillisNow;
unsigned long MillisThen;

//-- Figure PWM based on current state

byte StepColor(byte Color, float Phi) {

byte Value;

    Value = (Pixels[Color].MaxPWM / 2.0) * (1.0 + sin(Pixels[Color].Step * Pixels[Color].StepSize + Phi));

//	Value = (Value) ? Value : Pixels[Color].MaxPWM;					// flash at dimmest points
//	printf("C: %d Phi: %d Value: %d\r\n",Color,(int)(Phi*180.0/PI),Value);

    return Value;
}


//-- Helper routine for printf()

int s_putc(char c, FILE *t) {
  Serial.write(c);
}

//------------------
// Set the mood

void setup() {

	pinMode(PIN_HEARTBEAT,OUTPUT);
	digitalWrite(PIN_HEARTBEAT,LOW);	// show we arrived

	Serial.begin(57600);
	fdevopen(&s_putc,0);				// set up serial output for printf()

	printf("WS2812 / SK6812 array exerciser\r\nEd Nisley - KE4ZNU - February 2017\r\n");

/// set up Neopixels

	strip.begin();
	strip.show();

// lamp test: run a brilliant white dot along the length of the strip

	printf("Lamp test: walking white\r\n");

	strip.setPixelColor(0,FullWhite);
	strip.show();
	delay(250);

	for (int i=1; i<NUMPIXELS; i++) {
		digitalWrite(PIN_HEARTBEAT,HIGH);
		strip.setPixelColor(i-1,FullOff);
		strip.setPixelColor(i,FullWhite);
		strip.show();
		digitalWrite(PIN_HEARTBEAT,LOW);
		delay(250);
	}

	strip.setPixelColor(NUMPIXELS - 1,FullOff);
	strip.show();
	delay(250);

// fill the array, row by row

	printf(" ... fill\r\n");

	for (int i=NUMROWS-1; i>=0; i--) {				// for each row
		digitalWrite(PIN_HEARTBEAT,HIGH);
		for (int j=NUMCOLS-1; j>=0 ; j--) {
			strip.setPixelColor(PINDEX(i,j),FullWhite);
			strip.show();
			delay(100);
		}
		digitalWrite(PIN_HEARTBEAT,LOW);
	}

// clear to black, column by column

	printf(" ... clear\r\n");

  for (int j=NUMCOLS-1; j>=0; j--) {				// for each column
		digitalWrite(PIN_HEARTBEAT,HIGH);
    for (int i=NUMROWS-1; i>=0; i--) {
			strip.setPixelColor(PINDEX(i,j),FullOff);
			strip.show();
			delay(100);
		}
		digitalWrite(PIN_HEARTBEAT,LOW);
	}

	delay(1000);

// set up the color generators

	MillisNow = MillisThen = millis();
	printf("First random number: %ld\r\n",random(10));

	Pixels[RED].Prime = 3;
	Pixels[GREEN].Prime = 5;
	Pixels[BLUE].Prime = 7;
  Pixels[WHITE].Prime = 11;
	printf("Primes: (%d,%d,%d,%d)\r\n",
         Pixels[RED].Prime,Pixels[GREEN].Prime,Pixels[BLUE].Prime,Pixels[WHITE].Prime);

	unsigned int PixelSteps = (unsigned int) ((BASEPHASE / TWO_PI) *
				RESOLUTION * (unsigned int) max(max(max(Pixels[RED].Prime,Pixels[GREEN].Prime),Pixels[BLUE].Prime),Pixels[WHITE].Prime));
	printf("Pixel phase offset: %d deg = %d steps\r\n",(int)(BASEPHASE*(360.0/TWO_PI)),PixelSteps);

	Pixels[RED].MaxPWM = 255;
	Pixels[GREEN].MaxPWM = 255;
	Pixels[BLUE].MaxPWM = 255;
	Pixels[WHITE].MaxPWM = 32;

	for (byte c=0; c < PIXELSIZE; c++) {
		Pixels[c].NumSteps = RESOLUTION * (unsigned int) Pixels[c].Prime;
		Pixels[c].Step = (3*Pixels[c].NumSteps)/4;
		Pixels[c].StepSize = TWO_PI / Pixels[c].NumSteps;				// in radians per step
		Pixels[c].TubePhase = PixelSteps * Pixels[c].StepSize;		// radians per tube

		printf("c: %d Steps: %5d Init: %5d",c,Pixels[c].NumSteps,Pixels[c].Step);
		printf(" PWM: %3d Phi %3d deg\r\n",Pixels[c].MaxPWM,(int)(Pixels[c].TubePhase*(360.0/TWO_PI)));
	}


}

//------------------
// Run the mood

void loop() {

	MillisNow = millis();
	if ((MillisNow - MillisThen) > UpdateMS) {
		digitalWrite(PIN_HEARTBEAT,HIGH);

    unsigned int AllSteps = 0;
		for (byte c=0; c < PIXELSIZE; c++) {				// step to next increment in each color
			if (++Pixels[c].Step >= Pixels[c].NumSteps) {
				Pixels[c].Step = 0;
				printf("Color %d steps %5d at %8ld delta %ld ms\r\n",c,Pixels[c].NumSteps,MillisNow,(MillisNow - MillisThen));
			}
      AllSteps += Pixels[c].Step;               // will be zero only when all wrap at once
		}

    if (0 == AllSteps) {
      printf("Grand cycle at: %ld\r\n",MillisNow);
    }

		for (int k=0; k < NUMPIXELS; k++) {				// for each pixel
			byte Value[PIXELSIZE];
			for (byte c=0; c < PIXELSIZE; c++) {				//  ... for each color
				Value[c] = StepColor(c,-k*Pixels[c].TubePhase);		// figure new PWM value
//				Value[c] = (c == RED && Value[c] == 0) ? Pixels[c].MaxPWM : Value[c];	// flash highlight for tracking
			}
			uint32_t UniColor = strip.Color(Value[RED],Value[GREEN],Value[BLUE],Value[WHITE]);
      strip.setPixelColor(k,UniColor);
		}
		strip.show();

		MillisThen = MillisNow;
		digitalWrite(PIN_HEARTBEAT,LOW);
	}

}

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