Tangible interaction · Healthcare Summer School · 2019
A musical instrument designed for one specific eleven-year-old. The goal wasn't to let Davide play music — it was to let him play with his class, at the same time, on the same piece.
Davide is eleven. He has infantile cerebral palsy and a motor disability. He's energetic, he loves every kind of sport, he listens to rap. He wanted a musical instrument.
He told us three things he needed from it: it had to be flexible, it had to be transportable, and it had to let him be part of a class. The third one is the brief. An instrument he could play alone in his room would have solved the wrong problem.
What made existing instruments unplayable for him wasn't vague. We wrote it down as four specific things his hands do:
Lack of precision. Small targets are unreachable.
Delayed and unrepeatable movements. The same gesture doesn't produce the same result twice — so anything requiring rhythmic accuracy fails.
Imprecise finger movements. Individual fingers can't be relied on, which rules out most keyboards and every string instrument.
Hand actions with inconsistent power. Force varies between one press and the next, so anything velocity-sensitive produces unpredictable sound.
Together these four points did most of the design work. They ruled out acoustic instruments entirely and pointed at large targets, forgiving timing, and a sound engine that doesn't care how hard you hit it.
01
Mapping needs and constraints on a wall, then looking at instruments that already solve parts of the problem — xylophones, tongue drums, capacitive keyboards — and testing hand positions with paper and upturned bowls before building anything.
02
Choosing what to laser-cut, what to 3D print and what to buy. Testing key surfaces and knob shapes as physical samples, because how something feels under an imprecise hand can't be judged from a drawing.
03
Laser cutting, 3D printing, wiring and gluing the working object.
The base of Davido is an IKEA Byllan — a laptop tray with a cushioned underside, meant for using a computer on the sofa.
It already solved three problems at once: it sits stably on a lap, it's shaped to rest against a body, and it's cheap and replaceable. Designing an equivalent from scratch would have taken the whole week and produced something worse.
What it cost us: the outline of the instrument was decided by a product we didn't design. The curved, kidney-shaped body isn't a formal choice — it's the shape of the tray. Every later decision, including where the keys could go, had to fit inside it.
Bigger buttons. Large, irregular key shapes covering as much of the surface as possible, so a whole hand or a fist lands on a note. Trade-off: fourteen keys instead of a wider range — fewer notes, but every one of them reachable.
Wearable. A strap and 3D-printed junctions so it attaches to his wheelchair or rests on his legs. It goes where he goes rather than waiting on a table.
Adaptable. Key surfaces and knobs designed as separate, swappable pieces — because the right texture and resistance can only be found by trying them.
Digital sound. An Arduino, an amplifier and a speaker instead of anything acoustic. A digital note sounds the same however hard it's struck, which directly answers the inconsistent-force constraint.
Piano layout. Keys arranged left to right by pitch, the arrangement every music teacher already knows. Trade-off: it inherits an ergonomic convention designed for hands unlike his — but it means he can be taught alongside everyone else, which was the point.
Plywood and eva rubber for the surfaces, felt for the keys, PLA for the printed junctions, velcro for what needed to be removable. A laser cutter and a 3D printer for everything else, and an off-the-shelf tray underneath.
[DA COMPLETARE: il prototipo suonava davvero? L'Arduino era collegato e funzionante, o l'oggetto era un mock-up non sonoro?]
Davido is an instrument to play, create and learn music with, alone or in a group. It's adaptive and wearable: it goes on the legs and attaches to the wheelchair, or it sits on a table like anyone else's instrument.
The photograph below is the one that says whether the project worked: four hands on the same surface at the same time. That was the brief.
[DA COMPLETARE: Davide l'ha provato? Cosa ha detto? Il progetto è proseguito dopo la summer school o si è fermato lì? E la domanda onesta: cosa non ha funzionato?]