In this project, Bluetooth Low Energy (BLE) is used to have a Feather nRF52840 and Circuit Playground Bluefruit communicate with each other to create a wireless 8-bit music synthesizer. The Feather has 12 buttons attached to its I/O pins. Each time a button is pressed, it sends a BLE packet to the Circuit Playground Bluefruit. When the Circuit Playground Bluefruit receives those packets, it swirls its on-board NeoPixels in a specific color and plays a tone.
The Bluefruit Playground App
This project was inspired by the tone example in the Bluefruit Playground App. With the app, you may connect your Circuit Playground Bluefruit board to your iOS device and then play with a series of examples, each with a user interface to allowing control of the Circuit Playground Bluefruit sensors.
One of those examples has a piano keyboard in the app and when the keys are pressed, they cause a tone to play from the Circuit Playground Bluefruit. I thought it would be cool to recreate this concept with hardware.