Metallic tong drums produce sound when their cut-to-tone sections are struck with a mallet, finger, or other implement, producing pleasant ambient notes. But why restrict such drums to mere human usage? Here I created a robotic drummer that strikes eight tongs/notes via solenoid strikers, controlled by an Arduino Opta micro PLC with MIDI input.
As seen in the build video below, the machine was designed around the dimensions of a propane tank drum. It’s made from laser-cut MDF, in a flexible “C” form that can expand and contract as needed. Eight flexible friction arms – typically employed for camera mounting – are attached around the circumference of the C. Each arm holds a solenoid striker, giving it flexibility for use with any number of percussion instruments.
Solenoids are triggered by an Arduino Opta with a solid-state relay (SSR) module. The SSRs output enough power to extend and retract the striker solenoids without the noise associated with mechanical relays.
Rather than programming it for a set riff or riffs, the system features MIDI input via an auxiliary serial and I2C adapter – designed for this project and now available purchase on Tindie. In theory, it could work with a range of MIDI input devices, but I also created a custom arcade-style MIDI input case – previously discussed here – as its primary interface.
Constructing this unit took a massive amount of learning, experimentation, and work, but it was a lot of fun and a great learning experience. I was also able to present it at my kids’ school, and at the Orlando Maker Faire last year, as seen at the end of the video. Code and CAD are available if you would like to examine things further!
