NeoPixel

Drive WS2812 / SK6812 RGBRed, Green, Blue LEDs with animated patterns. See the neopixel APIApplication Programming Interface reference for the full type surface.

Hardware

• Any ESP32 board
• NeoPixel-compatible LEDs (WS2812 or SK6812)
• USBUniversal Serial Bus cable

Code

import {NeoPixel} from 'mikro/neopixel'
import {sleep} from 'mikro/sleep'

const PIN = 8
const NUM_LEDS = 24

const pixels = NeoPixel(PIN, {count: NUM_LEDS}).orPanic('Failed to set up the LED strip')

// Maps a position from 0 to 255 on the color wheel to [r, g, b]
function wheel(pos: number): [number, number, number] {
  if (pos < 85) return [255 - pos * 3, pos * 3, 0]
  if (pos < 170) return [0, 255 - (pos - 85) * 3, (pos - 85) * 3]
  return [(pos - 170) * 3, 0, 255 - (pos - 170) * 3]
}

// Rainbow cycle
for (let offset = 0; ; offset = (offset + 1) % 256) {
  for (let i = 0; i < NUM_LEDS; i++) {
    const [r, g, b] = wheel((Math.floor((i * 256) / NUM_LEDS) + offset) % 256)
    pixels.setPixel(i, r, g, b).orPanic('setPixel failed')
  }
  pixels.show().orPanic('show failed')
  await sleep(20)
}

Connect the data-in wire to GPIOGeneral-Purpose Input/Output 8 (or change PIN in the code). Connect VCC to 5V and GNDGround (0V reference) to GNDGround (0V reference). For more than 8 LEDs, use an external 5V supply instead of the board's USBUniversal Serial Bus power.

The full example in the repository includes multiple patterns: rainbow, comet, breathe, sparkle, and color wipe. Each pattern is a separate module that takes the NeoPixel instance, LEDLight-Emitting Diode count, brightness, and duration as parameters.

Key concepts

• NeoPixel(gpio, {count}): claims the GPIOGeneral-Purpose Input/Output pin for the strip's data line and returns a Result with the handle.
• pixels.setPixel(index, r, g, b): sets a pixel's color, 0 to 255 per channel. Returns a Result.
• pixels.fill(r, g, b): sets all pixels to the same color.
• pixels.show(): pushes the pixel buffer to the hardware. Returns a Result.
• pixels.clear(): turns off all pixels (sets to black).
• pixels.end(): releases the hardware resources and the GPIOGeneral-Purpose Input/Output pin.

All methods that can fail return a Result, so you can use .orPanic() for quick prototyping or check .ok for production code.

Create project

pnpm

pnpm create mikro --template neopixel

npm

npm create mikro -- --template neopixel

yarn

yarn create mikro --template neopixel

bun

bun create mikro --template neopixel

Run it

pnpm

pnpm install
pnpm mikro flash  # only needed once per board
pnpm mikro dev

npm

npm install
npx mikro flash  # only needed once per board
npx mikro dev

yarn

yarn install
yarn mikro flash  # only needed once per board
yarn mikro dev

bun

bun install
bunx mikro flash  # only needed once per board
bunx mikro dev

The LEDs will cycle through animated patterns, each lasting 8 seconds.

View source on GitHub

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NeoPixel is a registered trademark of Adafruit Industries.