Itty Bitty MIDI Piano Sings With Solenoids

Toy pianos are fun to plink around on for a minute, but their small keyboards and even smaller sound make them musically uninteresting pretty quickly. [Måns Jonasson] found a way to jazz up a two-octave toy piano almost beyond recognition. All it took was thirty solenoids, a few Arduinos, a MIDI shield, and a lot of time and patience.

This particular piano’s keys use lever action to strike thin steel tines. These tines are spaced just wide enough for tiny 5V solenoids to fit over them. Once [Måns] got a single solenoid striking away via MIDI input, he began designing 3D printed holders to affix them to the soundboard.

Everything worked with all thirty solenoids in place, but the wiring was a bird’s nest of spaghetti until he upgraded to motor driver shields. Then he designed a new bracket to hold eight solenoids at once, with a channel for each pair of wires. Every eight solenoids, there’s an Arduino and a motor shield.

The resulting junior player piano sounds like someone playing wind chimes like a xylophone, or a tiny Caribbean steel drum. Check out the build video after the break.

Hate the sound of toy pianos, but dig the convenient form factor? Turn one into a synth.

8 thoughts on “Itty Bitty MIDI Piano Sings With Solenoids

  1. I’d probably place a thin amount of foam insulation around the part that the actuators strike to muffle the extra “clicky” or “tinny” sound that is inherent to metal on metal contact.

  2. Cool!

    At first I was thinking was going to be something like just the solenoid being used (which is somewhat with the tuned music wire (or whatever termed appropriately) as-is) and something more like bd594 or this:
    https://www.youtube.com/watch?v=Aq0IOJRy31U

    Or like this more-so:
    https://www.youtube.com/watch?v=fp4jQNa_9sY

    Was thinking then… when is someone going to demonstrate online the hacking of the refrigerator/freezer compressor clucking like a turkey or chicken or whatever the sounds that some do out of them straight through the mains? Never seen that demonstrated yet and you have to carefully listen for if I recorded it.

  3. I worked with a music professor on a similar project years ago, but it was a Steinway grand piano and he wanted the soft-touch ability (i.e. low velocity) — pretty tough to achieve with solenoids. Servos were noisy and steppers bulky, so solenoids they stayed. Pretty sure the Yamaha Disklavier uses solenoids, too.

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