Thanks to the amazing effort of Frank Boesing, the Teensy Audio Library now has native S/PDIF output.
Using a $1 TOSLINK connector, or just a red LED, you can get optical S/PDIF digital audio output.
Optical output is useful for projects where Teensy connects to grounded equipment. There are lots of ways to simply play sounds, but the Teensy Audio Library gives you Arduino-sketch controlled synthesis, mixing, effects & filters, analysis and much more. Sketch controlled sound is most useful when you connect more hardware to Teensy & use other Arduino libraries for inputs. But often that other hardware comes with ground connections that cause audio-corrupting ground loop problems with analog audio, like the DAC pin or the audio shield. Optical S/PDIF give you perfect digital audio output for those projects!
Click "Read more" for much more detail about the S/PDIF development....