The 'grains of sand' code is a great way to demo any LED matrix with an accelerometer, and the NeoTrellis M4 can make this even more entrancing by adding tactile, tap, and sound interaction as well.
This guide will show you how to get this code up and running on the NeoTrellis M4. A walk through the code will show you how you can get started making your own styles of interactions.
WARNING: This demo can be addictive - do not loan your NeoTrellis M4 running this demo out to others without being prepared to point them to this article and/or buy/setup one for them yourself!
To listen to the sounds, you can choose to use headphones, speakers, or a connection to your own amplifier: