Most synthesizers look and feel like appliances. They’re plastic boxes mass-produced in factories, efficient and functional but utterly lacking in personality or warmth. Pianos and guitars get to be handcrafted instruments with wood grain and visible joints, while synths are treated like glorified toasters with circuit boards inside. That disconnect between electronic music and tactile craft has always felt like a missed opportunity, especially when you consider how satisfying it is to play a real wooden keyboard.
One maker decided to fix this by building a fully functional synthesizer from scratch, using materials that sound completely impractical. The result is a compact, 34-key synth with a fiberglass-reinforced cardboard body, a steam-bent walnut frame, and individual keys handmade from oak and walnut. It looks like something between a vintage record player and a mid-century hi-fi component, with a turquoise fiberglass shell and warm wooden accents that feel more like furniture than electronics.
Designer: Gabriel Mejia-Estrella
The body starts as folded cardboard panels cut from a template, then gets layered with fiberglass cloth and epoxy until it transforms into a rigid, glossy shell. The process borrows from old automotive techniques where fiberglass shaped custom car bodies in the 1950s, giving the synth a retro-futuristic sheen. Around the perimeter sits a continuous steam-bent walnut strip with oval cutouts that mimic speaker grilles on vintage radios, adding visual warmth and a furniture-like presence.
The keys are where the craft really shows. Black keys are made from laminated walnut offcuts, while white keys are cut from oak for contrast and durability. Each key is individually shaped, drilled for a shared steel rod pivot, beveled to prevent jamming, then coated with fiberglass and sanded up to 3000 grit for a smooth finish. The result looks and feels closer to a piano than a typical plastic keyboard.
Underneath sits a custom flexible printed circuit with interdigitated copper pads and rubber dome switches. When you press a key, the dome collapses and bridges the pads, closing a circuit that a Teensy microcontroller scans continuously. The Teensy sends MIDI messages to a Raspberry Pi running Zynthian, an open-source synth platform packed with engines and presets, all displayed on a small touchscreen.
Of course, using cardboard and steam-bent walnut creates challenges the designer readily admits. Cardboard turned out to be impractical, requiring multiple fiberglass layers and tedious filling. Walnut is notoriously stubborn to bend, needing kerf cuts and boiling water to soften the fibers. The designer suggests foam board or 3D printing as easier alternatives and notes that more precise tools would have made the keys cleaner.
What makes this synth significant is how it challenges the assumption that electronic instruments have to be cold and industrial. By using wood, fiberglass, and visible handwork, it reintroduces warmth and personality into something usually purely functional. It’s less a finished product and more proof that synthesizers can be beautiful, tactile objects worth admiring even when silent.
The post Someone Built a Working Synth From Cardboard and Walnut Keys first appeared on Yanko Design.