Bygonebytes

Introduction


8 Pad Electronic Drum Kit

The next step on from sequencers is to build a simple electronic drum kit. The set up includes eight drum pads for a kick, snare, two toms, a floor tom, symbal and a hi-hat (open and closed). Looking around the internet I collected some ideas on building basic pads using layers of foam, aluminium (sensor) and on top a rubber pad for hitting so I assembled the pads in two rows of four with a slight arch to help with reach. The sensor I used is a common piezoelectric device placed between the foam and aluminium and wired out to the Raspberry Pi using screened cable. To connect the sensor to the Raspberry Pi I designed a simple HAT with eight comparators to provide clean input switching to the GPIO and bringing out the potentiometers used to set the trigger levels allows for the trigger sensitivity to be adjusted by the user.

My first attempt at the software for the Pi included a single kit, each sound sample could be selected on any of the eight pads. This means that you can place the drum sounds in roughly the same order as a real kit - with the exception of the kick drum (which should be on the floor) or you can mix it up a bit. As there are far more samples than just eight you are free to select any combination you want, in fact, I then went on to produce the software that lets you select between any sound from twelve drum kits on any pad. Additional features include setting pads to externally trigger a sequencer or some other device, a Reset to clear all changes and Save and Load options so you don't have to remember your kit selections.

A small number of bare comparator HAT boards left over - contact me for availability.

RPi_Drummer screen.


RPi Drummer Script and HAT details.