Alastair Roberts' Tactile Synth Gives Three-Year-Olds an Outlet for Their Musical Creativity

Software engineer Alastair Roberts has built a synthesizer with a difference: it's designed specifically for use by his three-year-old daughter.

"My daughter received a Montessori activity board full of switches and LEDs for her first birthday. Watching her twist knobs and flip the switches reminded me of the control surface of a synth, and I wondered if I could build a musical version — something simple, tactile, and creative that didn't require holding down buttons to keep the sound going," Roberts explains. "A year later I finally decided to build it. I had no prior hardware experience, so this became an excuse to learn about microcontrollers, CAD, PCB design, and 3D printing."

The pleasingly-tactile music-making machine began life with an Arduino Inventors Kit pulled from a desk draw and dusted off, which was wired to a series of potentiometers and inputs and programmed to provide corresponding MIDI messages as outputs. Rotary encoders were added as an alternative input, and the initial prototype was a success — picking up changes in its inputs and communicating them to an Apple Mac running a Python-based bridge to Logic Pro.

The addition of an M5Stack MIDI Synthesizer Unit, based on the Dream SAM2695 chip, allowed Roberts to remove the Mac — a bit of a pricey piece of gear to be allowing a three-year-old unsupervised playtime with — while an OLED display provided visual feedback in the form of a dancing panda animation.

The child-friendly enclosure for all these electronics was designed in Autodesk Fusion 360 — Roberts' first CAD project, he explains — and printed on a Bambu Labs A1 Mini. "Moving the circuit to a proper PCB felt daunting, so for the first version I hand-wired everything on a solderable breadboard," Roberts recalls. "The good: hanging out and drinking some wine with my friend, who kindly offered to help with the soldering. The bad: when the time finally came to close the two halves of the enclosure, stuffing the rats nest of wires inside ended up putting pressure on a bunch of the delicate soldered joints and breaking them."

The issue was fixed with a custom-designed PCB, created using Fusion 360's internal electronic design automation tool — a relatively straightforward and cheap-to-produce two-layer board. Three AA batteries provide power, and the unit was finished to acclaim from its recipient. "It’s been just over a week since my daughter unwrapped her new synth. It now lives on the shelf with her other toys, and so far it gets regular use and is holding up well," Roberts says. "After watching a few children and adults (musical and non-musical) play with it, I think there might be the germ of a real product here."

More information is available on Roberts' website; the maker has indicated that he's interested in building a small batch, or even launching a crowdfunding campaign for larger-scale production, and is scoping out interest, and hasn't ruled out a "more polished open-source version for makers."