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Bent Brooks, front view — a decorated skull with a crystalline white finish, long black ringlet curls, and a draped iridescent purple-and-green cap, built to look like Brook the singing skeleton from One Piece.

Build Log · Lo-Fi Sampler Module

Bent Brooks

ISD1820 Lo-Fi Sampler Fresh off the bench

A lo-fi sampler module built around the humble ISD1820 voice-recorder chip and stuffed inside a decorated skull — a love letter to Brook, the singing skeleton from One Piece. He comes preloaded with his signature singsong laugh — a bottomless yo-ho-ho-ho-ho — and a single pitch-bend knob drags that cackle anywhere from a slowed-to-a-crawl graveyard groan up to a squeaky, crumbling chipmunk warble. One button sets him off.

  • TypeLo-fi sampler module (one-off build)
  • HeartISD1820 voice-recorder IC
  • PreloadedBrook's singsong “yo-ho-ho” laugh (One Piece)
  • ControlsPlay button · pitch-bend knob (that's it)
  • OutputOnboard speaker — no amp needed
  • Power3× AA batteries
  • MemoryNon-volatile — the sample survives power-off
  • HousingDecorated skull — curls + iridescent cap
  • StatusFinished July 2026 — one of a kind

What it is

The ISD1820 is a dirt-cheap voice-recorder IC — the kind that lives in talking greeting cards. It records a few seconds of audio and plays it straight back, and because the memory is non-volatile, whatever you put on it stays put even after the batteries come out. On its own it's a toy. Bent to a purpose, it's a gloriously grimy little sampler.

For Bent Brooks I loaded up the one sample it will ever need — Brook's signature singsong yo-ho-ho-ho-ho laugh — and gave him a body to match: a skull with a sugar-crystal finish, a mane of black ringlets, and a draped, oil-slick purple-and-green cap. He is a one-trick instrument and the trick is the whole point.

Demo

Demo filmed by Onion Madder on the actual unit.

Controls & play

Play button
Sets Brook singing — press to fire off the preloaded sample.
Pitch-bend knob
Sweeps the sampling / playback frequency: crank it one way for a deep, dragging, half-speed groan; the other way for a fast, brittle, high-pitched squeal. Everything in between is fair game.

Under the hood

CoreISD1820 voice-recorder / playback IC
Pitch modOnboard sampling-frequency resistor (R4) swapped for a potentiometer, so the knob sweeps pitch and playback speed together
SamplePreloaded “yo-ho-ho-ho-ho” laugh — held in non-volatile memory
TriggerSingle momentary play button
OutputBuilt-in speaker — plays on its own, no external jack or amp
Power3× AA batteries
HousingDecorated craft skull — crystalline finish, ringlet-curl hair, iridescent draped cap
BuildCircuit-bent, wired, loaded, and finished by Onion Madder — fully one of a kind
The pitch trick here is the classic ISD1820 mod — lift the onboard R4 resistor and drop a potentiometer in its place. If you want to build your own, start with my guide to the blue breakout board itself: Four Modes, One Chip: the ISD1820 Breakout » I also mirror Darren Shaw's excellent walkthrough over in the DIY section: Modifying an ISD1820 into a Lo-Fi Sampler »

Brook is a character from One Piece (© Eiichiro Oda / Shueisha / Toei Animation), referenced here in tribute only — this is an unofficial, one-off fan build, not affiliated with or endorsed by the rights holders. All circuit work, wiring, and finish by Onion Madder.