Adafruit NeoPixel

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E-textile
Module: Adafruit Wearables
draft beginner
2019/09/26 ⚒⚒ 2019/08/28
Objectives
  • hook up a NeoPixel to a micro-controller program the pixel (to do)
See also

Objectives

  • hook up a NeoPixel to a micro-controller program the pixel (to do)

See also

  • Quality: draft
  • Difficulty: beginner

Introduction

In this article we describe the Flora RGB Smart NeoPixel version 2

See also:

The pixel

Main characteristics:

  • 12.5mm diameter
  • 2.5mm total thickness
  • 800 KHz speed protocol
  • Chainable design, meaning that you can connect several of these to one pin and chain them
  • 5-9VDC power (can run at 3.5V but color will be dimmed), constant current 18.5mA per LED (~55mA max total per pixel)

Hooking up a NeoPixel

According to Hook up alligator clips (retrieved Aug 2019), a NeoPixel must be connected with three wires to a FLORA-type board. Depending on the board, the wiring is bit different. E.g. on a GEMMA, the signal must be wired from A1.

Wiring with a GEMMA
Board NeoPixel
VOUT

Power output

+
GND

Grounding

-
D1 / ~A0

General Purpose Input Ouput

↑ (arrow pointing towards the inside)
Gemma - NexPixel wiring (improvised): Read is power, black is grounding and white is the signal


Wiring with a Circuit Playground Express
Board NeoPixel
VOUT +
GND -
A1

General Purpose Input Ouput

↑ (arrow pointing towards the inside)

MakeCode example for the Circuit Playground Express

This does the following:

  • On start, a short animation of 5 seconds of the strip
  • After that all turned to black (off)
  • Pressing Button A -> All Pixels will be blue
  • Pressing Button B -> All Pixels will be red
  • Pressing A3 (or the attached copper) band: Three loops that will light up with different colors. After that: all set to yellow
Connecting a NeoPixelstrip to a playground Express
// Button A down
input.buttonA.onEvent(ButtonEvent.Down, function () {
    // show blue on all pixels
    strip.setAll(0x0000FF)
})
// Button B down
input.buttonB.onEvent(ButtonEvent.Down, function () {
    // show red on all pixels
    strip.setAll(0xFF0000)
})
// A3 touched (you could add a strip of copper)
input.touchA3.onEvent(ButtonEvent.Down, function () {
    for (let index2 = 0; index2 <= strip.length(); index2++) {
        strip.setPixelColor(index2, 0xff0000)
        pause(100)
    }
    for (let index22 = 0; index22 <= strip.length(); index22++) {
        strip.setPixelColor(index22, 0x00ff00)
        pause(100)
    }
    for (let index3 = 0; index3 <= strip.length(); index3++) {
        strip.setPixelColor(index3, 0x0000ff)
        pause(100)
    }
    for (let index32 = 0; index32 <= strip.length(); index32++) {
        strip.setPixelColor(index32, 0xffff00)
    }
})
let strip: light.NeoPixelStrip = null
// mount an external Neopixel strip on pin A1 with 30
strip = light.createStrip(pins.A1, 30)
// show default animation for 5 seconds
strip.showAnimation(light.rainbowAnimation, 5000)
// Turn it off (make colors black)
for (let index = 0; index <= strip.length(); index++) {
    strip.setPixelColor(index, 0x000000)
}



Programming a strand of pixels

This also works with a single pixel...

Links

Official general documentation (read this)

Tutorials