Arduino Library for WS2812B LED Strips

Based off pololu-led-strip-arduino

Summary

This is a library for the Arduino for controlling WS2812B LED strips

Supported Platforms

This library currently supports any board based on the ATmega168, ATmega328P, ATmega32U4, or ATmega2560 which runs at 8 MHz, 16 MHz, or 20 MHz.

Getting Started

Hardware

The LED strip's input connector has two pins that should be connected to the Arduino. The LED strip's ground will need to be connected to one of the Arduino's GND pins, and the LED strip's signal input line will be need to be connected to one of the Arduino's I/O lines. The example sketch assumes the signal line is connected to pin 5.

You will also need to connect a suitable power supply to the LED strip using one of the power connectors. The power supply must be at the right voltage and provide enough current to meet the LED strip's requirements.

Software

You can manually install the library:

1. Download the latest version from GitHub.
2. Drag the "ws2812B-arduino" folder into the "libraries" directory inside your Arduino sketchbook directory. You can view your sketchbook location by opening the "File" menu and selecting "Preferences" in the Arduino IDE. If there is not already a "libraries" folder in that location, you should make the folder yourself.
3. After installing the library, restart the Arduino IDE.

Example

An example sketch is available that shows how to use the library. You can access it from the Arduino IDE by opening the "File" menu, selecting "Examples", and then selecting "ws2812B-arduino". If you cannot find the example, the library was probably installed incorrectly and you should retry the installation instructions above.

Timing Details

This library takes about 1.1 ms to update 30 LEDs (1 meter). The LED strips use a high speed one-wire protocol with relatively strict timing requirements, so this library disables interrupts to ensure reliable color transmission. Unfortunately, disabling the interrupts causes problems in other libraries that uses interrupts, such as the Serial library and the functions like millis() that keep track of time.

Documentation

LED

The library defines a type named LED which can be used to represent individual LEDs in the strip. The type is defined like this:

typedef struct LED {
        uint8_t green;
        uint8_t red;
        uint8_t blue;
        struct LED* next;
        LED() {};
        LED(uint8_t r, uint8_t g, uint8_t b) : red(r), green(g), blue(b) {};
    };

The fields red, green, and blue are numbers between 0 and 255 and represent the brightness of the red, green, and blue color components respectively. The field next represents the next LED in the LED strip.

LEDStrip

The library defines a class named LEDStrip.

This class has no default constructor and should be initialized with the following constructor:

• LEDStrip(LED* start, unsigned int size)
  Creates an LEDStrip object. The start parameter should be a pointer to a linked list of LED objects. The size parameter is the number of LEDs in the strip.

• void write(unsigned char pin)
  Writes the colors pointed by the start attribute of the LEDStrip object to the LED strip. The pin parameter is an unsigned char should be the number of the Arduino pin that the LED strip's data input line is connected to. For ATmega2560-based boards such as the Arduino Mega, only the following pins are usable: 0–5, 10–13, 18–41, and 50–61 (ports A through G).

• void writeRange(unsigned char pin, unsigned int count)
  Writes the number of colors specified by count at the start attribute of the LEDStrip object to the LED strip. The pin parameter follows the same constraints as above.