Introduction to Drum Master
Drum Master has been a long term project for me. I first started in 2007, and created a drum set that worked quite well (especially given my lack of electronics experience). However, there were some problems with it. The most annoying factor was that I needed a laptop for sample playback; in addition, there were some intermittent problems with the sensitivity of the pads. Calibration and setup was difficult, as you had 32 analog channels, each with its own physical potentiometer plus socketable resistors for adjustment. While the design worked, and in fact started me off on a pathway of electronics discovery, I found that I didn't bother to play much, due to the setup required. It was not something you could turn on and start playing; you had to move the laptop, hook up USB and speakers, etc.
After a number of years and multiple other projects, I figured that I would give this another try, using the things I had learned and new technologies which had become available.
After a few false starts, using things like a Raspberry Pi as the controller, I found what would end up being the correct microcontroller: the Teensy 3.1 with a daughterboard for audio playback. This allowed me to easily use an embedded microcontroller for both hardware polling and sound playback, which gives me a huge advantage over the previous revision (which needed a laptop to play back sounds).
The analog part of the system would include peak voltage detection hardware, to make sampling the piezo sensors easier and more accurate (thus addressing the issues with pad sensitivity).
For more information on how this system works, and how to build one yourself, read on!