Electronic drums are really the only option for drummers who live in apartments. While inexpensive electronic drum sets are available, they are little more than noise-making toys. High-end sets, on the other hand, can cost hundreds of thousands of dollars. Jeremy Oden created eXaDrums, an open source, low-latency electronic drum system, to make high-end hardware and software accessible to DIYers.
The triggers (the drum pads that you strike), a trigger board that registers those strikes, and a processing unit make up the three major subsystems of electronic drum sets. The processing unit can either generate sound (via synthesis or sampling) or send a MIDI signal to another system. All of this hardware, as well as the software to run it, is included in the eXaDrums project. Oden carefully designed that software to be operating system agnostic and to have a low latency so that there is no audible delay between a beat and the sound output.
The trigger board is an Arduino Nano Every shield. The Nano Every is an inexpensive board that keeps costs low. It can also read eight analogue inputs at high speeds, allowing it to support an entire drum kit’s worth of drum pads. This includes seven single-zone pads as well as an extra hi-hat. It has a sample rate of 9,000 samples per second per channel.
The Nano then sends MIDI notes to a Raspberry Pi running the eXaDrums software via USB. That software interprets the incoming MIDI signals and then outputs the sound that the user configures for each drum pad. All of this, plus a touchscreen interface, is housed in a neat 3D-printed enclosure that the user can attach to their electronic drum kit.