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Loopy Louie, finished - a repurposed Gooey Louie game head (a bald, big-nosed cartoon man on a green oval base) with its big white googly eyes glowing bright green from LEDs set into the pupils.

Build Log · Lo-Fi ISD1820 Looper

Loopy Louie

ISD1820 Lo-Fi Looper Green-eyed & glowing

A lo-fi record-and-loop box built around the humble ISD1820 voice-recorder chip and crammed into a gutted Gooey Louie game head - yes, the one where you yank boogers out of his nose. Feed him a few seconds of anything and he loops it back forever, with a pitch knob that drags the loop from a slow, gluey groan up to a chattery squeal. An added amplifier makes him actually loud, and two green LEDs drilled into his googly eyeballs mean he stares right back while he chews on your sound.

  • TypeLo-fi ISD1820 looper (one-off circuit-bent build)
  • HeartISD1820 record / playback IC
  • LoopRecord a few seconds - it plays back and repeats
  • PitchKnob on the sampling-frequency resistor - warps speed & pitch
  • AmpAdded onboard amplifier + speaker - louder than the bare chip
  • EyesGreen LEDs set into the drilled-out googly pupils
  • ControlsRecord · play · loop · pitch · volume · power
  • HousingHasbro “Gooey Louie” game head on its green base
  • PowerInternal vape-cell pack (~3.7V)
  • StatusFinished July 2026 - one of a kind

What it is

The ISD1820 is a dirt-cheap voice-recorder IC - the guts of a talking greeting card. It records a few seconds of audio into non-volatile memory and plays it right back, and it'll happily loop that clip until you stop it. On its own it's a toy. Bent to a purpose - a pitch mod, a real amplifier, and a face - it's a gloriously grimy little looper.

Loopy Louie lives in a Gooey Louie, Hasbro's mid-90s pull-the-boogers game. The head was the perfect enclosure: hollow, expressive, and already staring. I gutted the original game, dropped in the ISD1820 and an amp, ran the controls out through his cheek, and put green LEDs where his pupils used to be. He's Bent Brooks' cousin - same chip, same pitch trick, very different attitude.

The build, start to finish

The donor toy before modding - an intact Gooey Louie game head with plain white googly eyes, a big nose, a pink open mouth, on a green oval base.
Before: one innocent Gooey Louie, fresh from the thrift gods.
The toy fully disassembled on satin: the green base, the two peach halves of the head shell, the separate nose-and-lip piece, and the white googly-eye assembly.
Decapitated and gutted. Every game mechanism comes out.
Inside the opened head - the ISD1820 recorder board, a small round speaker, a large blue capacitor, and a tangle of colored hookup wire packed into one peach shell half, with the green base and empty shell half beside it.
The new organs: ISD1820, amp, speaker, and a nest of wire.
The two white googly eyeballs with green LEDs installed where the pupils were drilled out, red and white lead wires running from the backs.
Pupils drilled out, green LEDs seated in, leads run.
Close-up of the two eyeballs in hand, clear LED domes seated in the black pupils - one eye has an extra small hole drilled just off-center.
…and one honest little drill slip. He's got character now.
Finished Loopy Louie from a high angle - green-lit eyes and the added controls down the right side of the face and neck: the green record and black play buttons, the loop toggle, the pitch knob at the back of the head, the volume knob by the mouth, and the power switch on the neck.
Buttoned back up, controls down the cheek, eyes lit.

Controls & play

Record — green button
Hold to record - feed him a voice, a note, a scrap of a song, whatever's in earshot. The microphone sits in his ear.
Play — black button
Fires the recorded clip once, straight through.
Loop — toggle
Flip it and the clip runs back to back until you flip it off - the whole point of the box.
Pitch — green knob at the back of the head
Sweeps the sampling / playback frequency: one way for a deep, dragging, half-speed groan; the other for a fast, brittle, high squeal. Everything between is fair game.
Volume — green knob by the mouth
Sets how loud the onboard amp drives the speaker.
Power — switch on the neck
Toggle on the supply - an internal vape-cell pack. Eyes light green when he's awake.

Under the hood

CoreISD1820 record / playback IC
LoopRecords a few seconds to non-volatile memory and plays it back on repeat
Pitch modOnboard sampling-frequency resistor (R4) swapped for a potentiometer, so the knob sweeps pitch and playback speed together
AmplifierAdded amp stage driving the speaker - noticeably louder than the ISD1820's own output
EyesTwo LEDs installed in the drilled-out googly-eye pupils, glowing green
ControlsGreen record button, black play button and loop toggle down the side of the head; pitch knob at the back of the head, volume knob by the mouth, power switch on the neck. Microphone in the ear.
OutputInternal speaker - plays on its own, no external jack
PowerInternal parallel pack of salvaged vape cells (~3.7V) - see how I build the pack. The ISD1820 runs happily at 3.7V, and wiring the cells in parallel buys double the runtime instead of more voltage.
HousingHasbro “Gooey Louie” game - head shell + green base, original game guts removed
BuildCircuit-bent, wired, amped, 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. Same chip and mod as my Bent Brooks build - and the same blue ISD1820 breakout I walk through in my own guide: 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 »

Gooey Louie is a game by Hasbro (© Hasbro), referenced here in tribute only - this is an unofficial, one-off circuit-bent build, not affiliated with or endorsed by the rights holders. All teardown, wiring, amping, and finish by Onion Madder.