Adding Color

The WS2812, also known as the Adafruit NeoPixel, is a programmable RGB light-emitting diode (LED). It consists of a controller and three LEDs in the colors red, green, and blue. There is a data byte in the controller for the brightness of each individual LED. This means that a NeoPixel can display up to 16,777,216 colors. NeoPixels are available both as a single component and pre-installed on various carriers. The best-known forms include the LED strip, the matrix, and rings [1] of various sizes.

Each NeoPixel has four connectors, two of which are for the 5V operating voltage. The other two connectors DI (Data In) and DO (Data Out) are used for asynchronous serial data transmission. The output (DO) of one WS2812 can be connected to the input (DI) of the next WS2812, so in theory, you can create an arbitrarily long chain of NeoPixels. One thing you need to bear in mind, though, is that data transmission can take a while. If it takes too long, the LEDs will start to flicker. But if you have 1,024 LEDs in series, it is still possible to supply them with data 30 times per second, and flicker is undetectable for us humans at this frame rate.

The signal for controlling the LEDs has a very special structure: The individual data bits are coded with a pulse width modulation (PWM) signal. The pulse-pause ratio of the signal defines whether it is a one or a zero. This method reduces susceptibility to interference. To avoid overloading this text with technical details, I'll just point you in the direction of the WS2812 data sheet [2] instead. It describes precisely how the protocol works, and it has the full details of the WS2812.

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