Remember the holophonor from Futurama? It was (will be?) a musical instrument that would project holograms depending on the mood of the note played.

Being a futuristic instrument, the inner workings of the holophonor are unknown. However, the basic idea of being able to detect the frequency of musical notes is something we can possibly emulate. And that is what we'll explore in this guide using a fairly simple technique.

We'll also use the frequency detection to drive NeoPixels (our version of the holophonor) and also show how a TFT Gizmo can be used to display the note information.

Which Circuit Playground?

The technique used here to estimate the audio frequency is fairly simple. It relies on constantly sampling the microphone and analyzing the results. Therefore, the more powerful the processor, the better.

Parts

The following parts are used in this project: