A clock that never needs setting, never drifts, and announces the hour by physically rotating machined aluminum wheels — that is what Clough42 handed over at Toolroom Takeover 2026. The catch is that the thing everyone calls "electromechanical" is running a microcontroller, a GPS receiver, and two stepper drivers underneath the brass-and-aluminum shell.
James (Clough42) built the clock as a gift for fellow YouTube machinist Rowan of Not an Engineer. Most gifts in that exchange are purely mechanical — a vise, a fixture, something turned on a lathe. This one keeps its own time by listening to satellites. A u-blox GPS module pulls the timestamp riding along inside every GPS signal, which is the same atomic-clock-derived time the whole constellation broadcasts. The clock has no navigation function at all; it just wants the seconds.
Pico, GPS, and two TMC2208s
A Raspberry Pi Pico sits at the middle of it. The RP2040 runs its dual Cortex-M0+ cores at 133 MHz, which is far more headroom than a clock needs, but it gives you two hardware UARTs — one for the GPS module, one free for debugging. The u-blox board streams NMEA sentences at 9600 baud on 3.3V logic, so it wires straight to the Pico's GP0/GP1 pins with no level shifter.
Turning the numbered wheels falls to a pair of TMC2208 stepper drivers. Those are the quiet ones — the StealthChop mode in the TMC2208 pushes switching noise above hearing range, so a clock sitting on a desk does not buzz every minute. Microstepping down to 1/256 also means each wheel can creep into position without visible stepping. A small display and two buttons let Rowan pick a time zone and flip between 12-hour and 24-hour readouts, which is the part that makes this mechatronics rather than a split-flap.
The metalwork matters too. Several parts came off James's heavily modified Precision Matthews PM-728 mini mill, now running a Masso controller, with the rest 3D-printed.
Build it yourself
The electronics half of this project is genuinely approachable for a capstone team. A Raspberry Pi Pico, a NEO-6M GPS breakout, two TMC2208 modules, two NEMA 17 steppers, and a 128x64 OLED will get you a working prototype on a breadboard before you machine anything. The gotcha most people hit: TMC2208 boards need their UART pin configured or they silently fall back to the jumper-set microstep resolution, and a GPS module can take 30 seconds or more for a cold fix indoors, so test near a window with the antenna pointed at open sky.
Watch the build log on Hackster, then start with the GPS half alone — get NMEA sentences printing over serial before you connect a single stepper.
Originally published on blog.circuit.rocks.
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