Neopixels, APA102 and other LEDs

The term LED, short for Light Emitting Diode is quite ambiguous. There is the humble LED, used to signify that a device is on and to say “hello world” when building your first circuit, but there are many others. We used Neopixels, a brand name for WS2811/12 LEDs. These super bright LEDs run from a 3.3V or 5V power supply and use carefully timed pulses to communicate the state of LEDs. Now as we learned in the tutorial, this causes issues as we have to use the GPIO pins, specifically a pin that can perform PWM, and this forced us to disable analogue audio output. But there are other LEDs that we can use instead of the Neopixel, and this is in the form of the APA102 series. These LEDs use the SPI interface, a hardware interface that is capable of sending data much faster to the LEDs, enabling them to be used in projects such as those using Persistence of Vision. APA102 LEDs do not require any additional configuration changes as they do not interfere with audio output. Lots of Pi related companies are using the APA102 instead of the WS2811/12 as it removes the sticky issue of audio configuration changes and provides an easier way to use super bright, individually controllable LEDs with the Raspberry Pi.