This Smartwatch Has A Laser, A Jukebox, And A Coin Flipper

Most DIY smartwatch builds chase the same handful of goals: fitness tracking, notification mirroring, maybe a custom watch face or two. ddominik’s open-source build mostly skips that list in favor of features that exist purely because they’re fun to have on your wrist.

What They Built

The watch is built around a Waveshare RP2040-Matrix board with a built-in 5x5 LED matrix, paired with an OLED display, a 5V boost converter, and a buzzer. On top of basic timekeeping, it packs a 5mW laser module with a roughly 3km nighttime range, NeoPixel matrix animations including a plasma effect and a countdown sequence, an 8-bit “jukebox” that plays retro game themes by manipulating PWM frequencies through the buzzer, a digital notepad for storing phone numbers, a temperature reading pulled from the RP2040’s internal sensor, and a coin-flipper app for settling bets.

How They Did It

ddominik describes the build process candidly as a learning project, complete with a soldering mistake that let the magic smoke out of the voltage converter, fixed with some manual PCB grinding and a generous application of hot glue and duct tape. The result is a self-described “ultra-raw prototype” — fully working, but with the exposed solder joints and bulkier footprint that come with a first hardware pass.

Why It’s Worth Your Time

It’s a refreshing change of pace from the fitness-tracker-or-notification-hub formula most DIY smartwatches default to, and a good demonstration that a watch project’s value doesn’t have to come from practicality.

Go See It

ddominik’s full project writeup is on Hackster.io, with source code on GitHub.