TS-TAP4 – tactile Arduino drum machine with looper

As a bass player sometimes I want a backing drum track for music practice, so I built myself this little drum sequencer, a unique touch-sensitive drum machine.
I just need to tap a rhythm on its touch sensors and it will start looping my sequence right away.

This project is based on an Arduino Nano/Arduino Uno. The sound samples are unsigned 8 bit 8000 Hz WAV files that have been converted to header files in order to be compiled with the rest of the code.
The touch interface works via capacitive sensing, there’s an Arduino library just for that. One of the drawbacks of using capacitive touch sensors with a battery-powered circuit is that grounding is unreliable. For this reason I surrounded the device with two rails of conductive copper tape, so that holding the device will naturally provide some grounding through the user’s hands.

An LM386 power amplifier in a gain=200 configuration is used to drive the 8Ω speaker.
The whole circuit is powered by a single rechargeable 18650 cell connected to a TP4056 charger module with USB input, which delivers a steady output at 5V.
I fitted everything inside a wooden trinket box I bought specifically for this purpose, as it looked like a drum to begin with. And I love when wood and electronics get together.

Download the source code for this project: github.com/TuriSc/TS-TAP4