Using Raspberry Pi to drive WS2812B LEDs

OK,

I have followed this set up:

http://www.tweaking4all.com/hardware/arduino/arduino-ws2812-led/

Using the wiring diagram including the external +5v and tying both grounds together. The only thing I have omitted is the 470 ohm resister.

Here is my code:

#include <Adafruit_NeoPixel.h>

 

 

#define PIN 6

 

 

// Parameter 1 = number of pixels in strip

// Parameter 2 = Arduino pin number (most are valid)

// Parameter 3 = pixel type flags, add together as needed:

//   NEO_KHZ800  800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)

//   NEO_KHZ400  400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)

//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)

//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)

Adafruit_NeoPixel strip = Adafruit_NeoPixel(1, PIN, NEO_GRB + NEO_KHZ800);

 

 

// IMPORTANT: To reduce NeoPixel burnout risk, add 1000 uF capacitor across

// pixel power leads, add 300 - 500 Ohm resistor on first pixel's data input

// and minimize distance between Arduino and first pixel.  Avoid connecting

// on a live circuit...if you must, connect GND first.

 

 

void setup() {

  strip.begin();

  strip.show(); // Initialize all pixels to 'off'

}

 

 

void loop() {

  // Some example procedures showing how to display to the pixels:

  colorWipe(strip.Color(255, 0, 0), 50); // Red

  colorWipe(strip.Color(0, 255, 0), 50); // Green

  colorWipe(strip.Color(0, 0, 255), 50); // Blue

  // Send a theater pixel chase in...

  theaterChase(strip.Color(127, 127, 127), 50); // White

  theaterChase(strip.Color(127,   0,   0), 50); // Red

  theaterChase(strip.Color(  0,   0, 127), 50); // Blue

 

 

  rainbow(20);

  rainbowCycle(20);

  theaterChaseRainbow(50);

}

 

 

// Fill the dots one after the other with a color

void colorWipe(uint32_t c, uint8_t wait) {

  for(uint16_t i=0; i<strip.numPixels(); i++) {

    strip.setPixelColor(i, c);

    strip.show();

    delay(wait);

  }

}

 

 

void rainbow(uint8_t wait) {

  uint16_t i, j;

 

 

  for(j=0; j<256; j++) {

    for(i=0; i<strip.numPixels(); i++) {

      strip.setPixelColor(i, Wheel((i+j) & 255));

    }

    strip.show();

    delay(wait);

  }

}

 

 

// Slightly different, this makes the rainbow equally distributed throughout

void rainbowCycle(uint8_t wait) {

  uint16_t i, j;

 

 

  for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel

    for(i=0; i< strip.numPixels(); i++) {

      strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));

    }

    strip.show();

    delay(wait);

  }

}

 

 

//Theatre-style crawling lights.

void theaterChase(uint32_t c, uint8_t wait) {

  for (int j=0; j<10; j++) {  //do 10 cycles of chasing

    for (int q=0; q < 3; q++) {

      for (int i=0; i < strip.numPixels(); i=i+3) {

        strip.setPixelColor(i+q, c);    //turn every third pixel on

      }

      strip.show();

 

 

      delay(wait);

 

 

      for (int i=0; i < strip.numPixels(); i=i+3) {

        strip.setPixelColor(i+q, 0);        //turn every third pixel off

      }

    }

  }

}

 

 

//Theatre-style crawling lights with rainbow effect

void theaterChaseRainbow(uint8_t wait) {

  for (int j=0; j < 256; j++) {     // cycle all 256 colors in the wheel

    for (int q=0; q < 3; q++) {

      for (int i=0; i < strip.numPixels(); i=i+3) {

        strip.setPixelColor(i+q, Wheel( (i+j) % 255));    //turn every third pixel on

      }

      strip.show();

 

 

      delay(wait);

 

 

      for (int i=0; i < strip.numPixels(); i=i+3) {

        strip.setPixelColor(i+q, 0);        //turn every third pixel off

      }

    }

  }

}

 

 

// Input a value 0 to 255 to get a color value.

// The colours are a transition r - g - b - back to r.

uint32_t Wheel(byte WheelPos) {

  if(WheelPos < 85) {

    return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

  }

  else if(WheelPos < 170) {

    WheelPos -= 85;

    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);

  }

  else {

    WheelPos -= 170;

    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);

  }

}

 

It is a slightly modified Adafruit testing sketch. The only difference I believe is in the line 12 where I have changed the number of NeoPixels to 1 instead of 60.

When the positive wire is connected and disconnected and reconnected again I get a flash of light from the LED and then nothing else.

Nathan

sweet

??

??