Attach your Circuit Playground Express via USB to your preferred MIDI instrument. You can use a digital audio workstation (DAW) on your computer or use a USB MIDI passthrough to connect to a hardware instrument (like a robot xylophone).
Stomp, slap, bang or pound on the stomping pads to send beautiful music out into the world. You can customize the code with your preferred MIDI notes. Think about experimenting with different instruments too, such as drums or weird sound effects.
The stomping pad mechanism can also be used with your feet, really opening up the musical possibilities. Since this project is setup as a series of digital inputs, you could also adjust the code to be an HID device or any other project that utilizes inputs. There's also potential for accessibility uses with the stomping pads.