This kind of thing is really common in the DIY synthesizer world. Here's a great resource: http://www.openmusiclabs.com/learning/digital/input-matrix-scanning/i

This kind of thing is really common in the DIY synthesizer world. Here's a great resource: http://www.openmusiclabs.com/learning/digital/input-matrix-scanning/index.html http://www.openmusiclabs.com/learning/digital/input-matrix-s...