Mallets Bot Plays a Full Octave of Wine Glasses

You’ve likely observed that when you tap a wine glass it emits a nice “plinking” sound, and perhaps also noticed that the liquid level changes its pitch. Taking this concept much further, hacker “Bitluni” set up 12 glasses in a wooden base, and created a set of solenoid-actuated arms to tap each one — a full octave — in sequence.

He used an ATmega32U4-based Pro Micro for control, allowing it to play pre-recorded — or even live sounds — via a MIDI interface. The solenoids themselves are switched by an I2C MOSFET driver board, powered by a separate 12V supply.

As with any build, there was some experimentation needed; including work to keep the physical control mechanism quiet, selectively using different types of glasses depending on the desired tone, and adding a rubber mallet to the end of each arm for a cleaner sound and easier tuning. He even found that using a huge syringe was extremely helpful when adding water to tune each glass. Bitluni notes that it’s wasn’t a particularly difficult build skill-wise, but took diligence to get it to work correctly.

The build is shown in the video below, including a performance just after the 7:00 mark. Code is available on GitHub, if you’d like to try a similar musical hack.