The cheap round AMOLED module has quietly become one of the most common parts in hobbyist hardware. It shows up in smartwatch clones, desk clocks and conference badges, and it almost always runs the demo firmware it shipped with.
The Badge, by curisama, is what happens when someone treats that module as an interface problem instead. It’s MIT-licensed firmware for the Waveshare ESP32-S3-Touch-AMOLED-1.75C, a 466×466 round AMOLED on an ESP32-S3, and it turns the thing into a general-purpose wearable input device. The project was published to GitHub on September 11 and is under active development.
What it does
- BLE trackpad and air mouse. The touch surface works as a trackpad, and moving the badge itself moves the cursor. It presents as a standard Bluetooth HID device, so any computer accepts it with no driver.
- Audio recording, up to 52 minutes to WAV
- Clock and timer
- Games and fidgets, including a liquid simulation with a boat floating in it
- Extra programmable keys
The creator’s build uses a milled aluminium case, which is what pushes it from dev board to object.
The engineering worth stealing
Two details are more instructive than the feature list.
The fluid simulation went from 3 FPS to 18 FPS. A circular 466×466 display is about 217,000 pixels, on a microcontroller. Getting a physics animation to run smoothly there is a real optimization job, and it’s the same class of problem a lot of creative-hardware projects give up on.
Standby battery life went from 11.9 to 19.6 hours by enabling CONFIG_PM_ENABLE and related tuning. That’s a 65% improvement from configuring power management properly rather than adding a bigger cell. On any battery-powered wearable, the ESP32’s power-management settings are usually where the missing hours are hiding, and they’re left at defaults far too often.
It also builds and runs on a PC. You can develop and test the interface as a desktop application, then flash it. Anyone who has debugged embedded UI by reflashing after every change will recognize how much time that saves. Firmware can also be flashed straight from a web browser, so trying it takes minutes.
Why it’s an interfaces story
A round screen is not a small rectangle. Menus, lists and keyboards all assume corners. A circular display forces genuinely different layouts, and there’s little established convention to lean on. Projects like this are where that vocabulary gets worked out, in public and under an open license, on hardware that costs very little.