Wikipedia defines arpeggio as such:
An arpeggio is a type of broken chord, in which the notes that compose a chord are played or sung in a rising or descending order. An arpeggio may also span more than one octave.
We're using the term arpeggiator a bit loosely here, basically this project turns your NeoTrellis M4 into a little lo-fi synth (or MIDI controller) that plays a sequence of notes with each button press. Each note of the sequence is positioned in relation to the original note pressed, and displayed on the NeoTrellis by lightning up its respective button on the grid.
All the available notes on the grid are taken from a particular musical mode (similar to a scale), which means pretty much anything you play will sound good. All together, this makes for an unusually fun and visually compelling musical experience - which I affectionately refer to as "Arpy".
You can either have the NeoTrellis M4 generate the audio itself, or have it send out MIDI messages to control another synth over USB MIDI such as on your computer or tablet
Here's what you'll need …
If you don't have a pair of powered speakers, these will work well …