This project is still in development, but is working. It is a Key/Scale Visualizer for a piano or MIDI keyboard. It is an Anvil application written in Python, but it is running as a standalone webserver on a Raspberry Pi 2 Zero W. It uses an LED strip set above the keys of a keyboard to display a scale in a particular key.

There are 13 predefined scales (Major, Minor, Major Blues, Minor Blues, Major Pentatonic, Minor Pentatonic, Major Harmonic, Minor Harmonic, Dorian, Phrygian, Lydian, Mixolydian, and Aeolian) and the user can define whatever scale he/she chooses using the half-step, whole step notation (ex. Locrian - 1, 2, 2, 1, 2, 2, 2).

I developed this for myself to make doing soloing via a midi keyboard easier by displaying the key/scale I'm to solo in. The color is definable (red, green, blue, yellow, cyan, magenta, white, and off) and the black keys show up in magenta.

The main web page for this application

After choosing a key and scale and clicking the LEDs On button

This is the Raspberry Pi 2 Zero W with a custom hat

Clicking the LED Parameters button

Clicking the Edit Modes button

Clicking the Edit icon button for a particular scale on the Edit Modes screen

Clicking the Add Scale Definition button on the Edit Modes screen