SparkCore-NeoPixel

A library for manipulating NeoPixel RGB LEDs for the Spark Core and Photon. Implementation based on Adafruit's NeoPixel Library. Library currently supports WS2812, WS2812B GRB 800kHz style pixels, strips and sticks! WS2811 RGB 400kHz style pixels, strips and sticks!

Also supports these less common pixels

Radio Shack Tri-Color LED Strip with TM1803 controller 400kHz bitstream.
TM1829 pixels, many details here.

Components Required

A Neopixel digital RGB LED (get at adafruit.com)
or a Radio Shack Tri-Color LED Strip (get at radioshack.com)
A Particle Shield Shield or breakout board to supply neopixel's with 5V (see store at particle.io)

Example Usage

See this flashable, rainbow example for details, or, in a nutshell:

Adafruit_NeoPixel strip = Adafruit_NeoPixel(PIXEL_COUNT, PIXEL_PIN, PIXEL_TYPE);
void setup() {
  strip.begin();
  strip.show();
}
void loop() {
  // change your pixel colors and call strip.show() again
}

Nuances

Make sure get the # of pixels, pin number, type of pixels correct
NeoPixels require 5V logic level inputs and the Spark Core and Photon only have 3.3V logic level digital outputs. Level shifting from 3.3V to 5V is necessary, the Particle Shield Shield has the TXB0108PWR 3.3V to 5V level shifter built in (but has been known to oscillate at 50MHz with wire length longer than 6"), alternatively you can wire up your own with a SN74HCT245N, or SN74HCT125N. These are rock solid.
Don't use getPixelColor() to move pixel data around when you are also using setBrightness(). When the brightness is set, all setPixelColor() calls will end up scaling colors to dim them before they are stored in memory. When using getPixelColor() the stored dimmed color is rescaled back up to the original color. However, due to some loss of precision with the math, it is not possible to recreate this color data perfectly. This is especially true with low brightness values. If you get and set color data repeatedly with a dimmed pixel, it will eventually continue to decrease in value until it is equal to zero.
When changing the brightness, always call setPixelColor() first with fresh un-dimmed color data, then call setBrightness(), and finally show().

Building locally

If you are building locally, place the files here:


../firmware/user/neo/extra-examples.cpp
../firmware/user/neo/neopixel.h
../firmware/user/neo/neopixel.cpp

Compile and program via DFU over USB with:

cd firmware/main
make clean all PLATFORM=photon APP=neo -s program-dfu

Useful Links
---

- NeoPixel Guide: https://learn.adafruit.com/adafruit-neopixel-uberguide
- Quad Level Shifter IC: [SN74ACHT125N](https://www.adafruit.com/product/1787) (Adafruit)
- Quad Level Shifter IC: [SN74HCT125N](http://www.digikey.com/product-detail/en/SN74HCT125N/296-8386-5-ND/376860) (Digikey)
- Quad Level Shifter IC: [SN74AHCT125N](http://www.digikey.com/product-detail/en/SN74AHCT125N/296-4655-5-ND/375798) (Digikey)