WS2812 datasheet(55/98 Pages) RASPBERRY-PI

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Arduino Library

Use

Doxygen-generated documentation for the Adafruit_NeoPixel library is available here. (https://adafru.it/Etk)

It’s assumed at this point that you have the Adafruit_NeoPixel library for Arduino installed and have run the

strandtest example sketch successfully. If not, return to the prior page for directions to set that up.

To learn about writing your own NeoPixel sketches, let’s begin by dissecting the strandtest sketch…

All NeoPixel sketches begin by including the header file:

#include <Adafruit_NeoPixel.h>

The block of code that follows is mostly descriptive comments. Only a couple lines are really doing any work:

// Which pin on the Arduino is connected to the NeoPixels?

// On a Trinket or Gemma we suggest changing this to 1:

#define LED_PIN

// How many NeoPixels are attached to the Arduino?

#define LED_COUNT 60

// Declare our NeoPixel strip object:

Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);

// Argument 1 = Number of pixels in NeoPixel strip

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

// Argument 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)

NEO_RGBW

Pixels are wired for RGBW bitstream (NeoPixel RGBW products)

The first few lines assign numbers to the symbols “LED_PIN” and “LED_COUNT” for later reference. It doesn’t

need to

be done this way, but makes it easier to change the pin and length where the NeoPixels are connected without

digging deeper into the code.

The last line declares a NeoPixel

object. We’ll refer to this by name later to control the strip of pixels. There are three

parameters or

arguments in parenthesis:

1. The number of sequential NeoPixels in the strip. In the example this is set to LED_COUNT, which was defined as

60 above, equal to 1 meter of medium-density strip. Change this to match the actual number you’re using.

2. The pin number to which the NeoPixel strip (or other device) is connected. Normally this would be a number, but

we previously declared the symbol LED_PIN to refer to it by name here.

3. A value indicating the type of NeoPixels that are connected. In most cases you can leave this off and pass just

two arguments; the example code is just being extra descriptive. If you have a supply of classic “V1” Flora pixels,

those require NEO_KHZ400 + NEO_RGB to be passed here. RGBW NeoPixels also require a different value here:

NEO_RGBW.

For through-hole 8mm NeoPixels, use NEO_RGB instead of NEO_GRB in the strip declaration. For RGBW

https://learn.adafruit.com/adafruit-neopixel-uberguide

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