NeoPixel Library for ESP32

A high-level NeoPixel (WS2812 / WS2812B) smart LED driver for BlueScript on ESP32. This package is built on top of the standard rmt library, utilizing a custom RMT encoder to seamlessly transmit GRB color data and reset pulses to a strip of LEDs without blocking the CPU or triggering garbage collection during transmission.

Installation

Install this package in your BlueScript project:

bscript project install https://github.com/bluescript-lang/pkg-neopixel-esp32.git

Usage

Basic: Control an LED Strip

Changes made to the LEDs (like setPixelColor or clear) only update the internal memory buffer. You must call show() to actually update the hardware LEDs.

import { NeoPixel, Colors } from "neopixel";

// 1. Initialize a strip of 10 LEDs connected to GPIO 15
const strip = new NeoPixel(15, 10);

// 2. Set overall brightness (0 - 255)
strip.setBrightness(128); // 50% brightness

// 3. Clear all LEDs to black
strip.clear();
strip.show();
time.delay(500);

// 4. Set individual pixel colors
strip.setPixelColor(0, 255, 0, 0);       // Pixel 0: Red (RGB)
strip.setPixelColorHex(1, Colors.Green); // Pixel 1: Green (Hex/Enum)
strip.setPixelColorHex(2, 0x0000FF);     // Pixel 2: Blue (Hex literal)
strip.show();
time.delay(1000);

// 5. Fill the entire strip with one color
strip.fill(255, 255, 0); // Yellow
strip.show();
time.delay(1000);

// 6. Cleanup hardware resources
strip.close();

API Reference

Class: NeoPixel

The primary class to control a strip of NeoPixel LEDs.

constructor(pin: integer, length: integer)

Initializes the LED strip and claims the underlying RMT hardware channel.

• pin: The GPIO pin number connected to the Data In (DIN) of the LED strip.
• length: The total number of LEDs in the strip.

setPixelColor(index: integer, r: integer, g: integer, b: integer): void

Sets the color of a specific LED in the internal buffer using RGB values.

• index: The zero-based index of the LED.
• r: Red component (0 to 255).
• g: Green component (0 to 255).
• b: Blue component (0 to 255).

setPixelColorHex(index: integer, hexColor: integer): void

Sets the color of a specific LED using a 24-bit hexadecimal integer.

• index: The zero-based index of the LED.
• hexColor: The color value (e.g., 0xFF0000 for Red, or Colors.Red).

fill(r: integer, g: integer, b: integer): void

Fills all LEDs in the strip with the same RGB color.

clear(): void

Sets all LEDs to Black (0, 0, 0). Equivalent to fill(0, 0, 0).

setBrightness(brightness: integer): void

Scales the brightness of all LEDs. The actual color output is calculated during show().

• brightness: Brightness level from 0 (off) to 255 (maximum brightness).

show(): void

Transmits the current color buffer to the physical LED strip via the RMT channel. This applies the current brightness scaling.

close(): void

Frees the underlying RMT channel and encoder resources. Call this if you no longer need to control the LEDs to free up memory and hardware peripherals.

Enums

Colors

A set of pre-defined standard 24-bit color hex codes for convenience.

Name	Hex Value
Black	0x000000
White	0xFFFFFF
Red	0xFF0000
Green	0x00FF00
Blue	0x0000FF
Yellow	0xFFFF00
Cyan	0x00FFFF
Magenta	0xFF00FF
Orange	0xFFA500