Handheld hardware, built in the open

Tiny handhelds.
Real circuits.

Legit Circuits is where I design pocket game consoles, music players and the boards inside them, from the first KiCad sketch to a printed shell in your hand. Every build is documented, and the good ones are headed for the shop.

See the builds → Read the build log

ESP32-P4
RP2350
ESP32-C3
PCM5102A
SSD1306

A 3D render of a small green circuit board with chips, a microSD socket, a USB-C port and a screen connector

USB-C charge + flash microSD game storage FPC 1.3" screen link

CAD · controller v0.7 A CAD render of the Saucelet controller shell with a D-pad cutout, four face-button holes and two round joystick openings

Flagship build ● In development

The Saucelet

A pocket game console that runs Legitsauce games natively, not in a browser tab. It's built around an ESP32-P4 with a square 1.3-inch screen, and the controller shell is designed in CAD and 3D printed here.

ESP32-P4 brain. Dual-core RISC-V with room for a real 3D renderer.
Full controls. D-pad, ABXY, twin sticks and shoulder buttons in a printed shell.
Games on microSD. Swap the card, swap the library.

Meet the Saucelet ↗

From CAD to bench

Every layer, designed here

Renders straight out of KiCad and OpenSCAD, next to the real boards and prints on the bench.

A small square screen showing a robot facing a glowing reactor, next to a Seeed Studio XIAO RP2350 board — Bench photoThe 1.3" screen rendering a 3D scene, next to the XIAO RP2350 that drew it

An exploded CAD view of a small handheld: front shell, screen, circuit boards, battery and back shell — CAD · explodedThe keychain console, layer by layer

A CAD render of a small white square case with a screen opening and a keyring loop — CAD · caseKeychain shell

A render of the keychain console from the front, with a black-and-white space game on its square screen and a keyring loop — Render · keychainA game on the keychain screen

A CAD render of a small copper-coloured box with a blue lid, two buttons and a screen showing Artist - Song — CAD · music playerPocket Navidrome player

A 3D render of the underside of the green circuit board with its USB-C port — KiCad · bottom sideThe Saucelet Lite board from underneath

A close-up of the small prototype screen showing a robot facing a glowing reactor, with its ribbon cable below — Bench photoA real frame on real glass

The parts bin

Built from parts you can buy

No mystery silicon. Every build uses chips and modules you can order today, so anything you see here is something you could build too.

Saucelet brain

M5Stack Stamp-P4

ESP32-P4 on a stamp-sized module. Fast enough for the native 3D renderer, with the I/O to drive a screen, microSD and a full set of controls.

Saucelet Lite · keychain

Seeed XIAO RP2350

Thumbnail-sized dual-core board. It drew the first native frames on the 1.3-inch screen and is the heart of the keychain console design.

Pocket music player

Seeed XIAO ESP32-C3

Wi-Fi in a tiny board. It streams MP3s from a home Navidrome server and decodes them on the chip, with no phone involved.

Line-out audio

TI PCM5102A DAC

A 32-bit I²S stereo DAC that turns decoded samples into a clean line-level signal with almost no extra parts.

Status screen

SSD1306 128×64 OLED

A crisp monochrome I²C panel for song titles and menus. The player's firmware re-checks it every few seconds, so it recovers by itself after a power glitch.

Game screen

ST7789 1.3" IPS, 240×240

A square full-colour panel on a thin ribbon. Small enough for a keychain and sharp enough to show a 3D scene.

Latest from the blog

Fresh off the bench

November 3, 2026 · 3 min read

A pocket Navidrome player on a XIAO ESP32-C3

Two buttons, a tiny OLED and a thumb-sized Wi-Fi board that streams and decodes MP3s from my home server, with no phone in the loop.

The shop

Kits and boards are on the way

When a build is solid enough to hand to someone else, it goes in the shop as a kit, a bare board or a printed shell. Nothing is for sale yet. Email me if you want to hear first.

DIY kits
Bare PCBs
Printed shells
Spare parts

Get notified →