This project is based on the work of John Park at Adafruit, specifically his Trellis M4 Beat Sequencers for the NeoTrellis M4 (https://learn.adafruit.com/trellis-m4-beat-sequencer).
I wanted something that would be easier for my students to hack, so I recreated Park's project using Scratch instead. It works much the same as the original, but students can remix the code to add different sounds or add different features without needing to know Circuit Python or Arduino.
I use the NeoTrellis M4 to control the computer, with each button coded for an individual keyboard stroke. Using the NeoTrellis and a visual on-screen menu, kids can mix their own beats on the computer. If you don't have a NeoTrellis, you can use the keyboard, a mouse click, or make your own controller with a Makey Makey or other device.
To use this project with the NeoTrellis, you'll need to upload the Circuit Python file called code_sequencer from my GitHub to your NeoTrellis. It's available at https://github.com/KaleidoscopeSci/NeoTrellis. For details on uploading code to your controller, see https://learn.adafruit.com/adafruit-neotrellis-m4
The Scratch program used to play your beats is available at https://scratch.mit.edu/projects/282414002/.