NeoPixel (ws2812)

Kaluma library for NeoPixel (ws2812) based on RP2 PIO (Programmable I/O)

This is a library to control NeoPixels (WS2812).

This supports only RP2-based boards (e.g. Raspberry Pi Pico) because it is based on PIO (Programmable I/O).

Wiring

Here is a wiring example.

Raspberry Pi Pico	NeoPixel
VBUS	PWR
GND	GND
GP0	IN

Install

npm install https://github.com/niklauslee/neopixel

Usage

const {NeoPixel} = require('neopixel');
const np = new NeoPixel(0, 12); // 12 pixels on GPIO0
np.setPixel(0, np.color(255, 0, 0)); // red on the 1st pixel
np.setPixel(1, np.color(0, 255, 0)); // green on the 2nd pixel
np.show();

API

Class: NeoPixel

A class for NeoPixel driver.

new NeoPixel(pin, length, options)

• pin <number> The pin number connected to NeoPixel's input.
• length <number> The number of NeoPixels.
• options <object> Options.
  • hz <number> Frequency for control. Default: 800000 (800KHz).
  • sm <number> Id (0~7) of PIO state machine used to control. Default: 0.

Create an instance of NeoPixel driver.

np.setPixel(index, color)

• index <number> Index of NeoPixel.
• color <number> Color value (24-bit) to set. You can use np.color(r, g, b) to get a color value from RGB.

Set color value to a NeoPixel. You have to call show() the color to be shown on NeoPixel.

np.getPixel(index)

• index <number> Index of NeoPixel.
• Return <number> Color value (24-bit) of the NeoPixel.

Returns the color value of the NeoPixel.

np.color(r, g, b)

• r <number> Red value (0~255).
• g <number> Green value (0~255).
• b <number> Blue value (0~255).
• Returns <number> Color value (24-bit).

Return a color value from RGB values.

np.clear()

Clear all NeoPixels by setting color to 0.

np.show()

Show the color values defined by setPixel() on NeoPixels.

Examples

• ex_spinning.js : Circular spinning on NeoPixels by changing colors.

TODO

• Assign id for PIO state machine automatically using StateMachine.getAvailableId().