From Old TicWatch to Smart Gear Knob
DIY creator Desmontei took the display and motherboard from a TicWatch Pro 3 and embedded them into a custom 3D printed gear knob, effectively turning a retired wearable into a fully functional automotive interface. Rather than letting the watch gather dust, he treated it as a compact, ready-made car display. This smartwatch upcycling project shows how a seemingly outdated device can gain a second life in a completely different context. The result is a Wear OS smartwatch hack that places a bright, glanceable screen directly on the gear lever. By reusing the existing hardware and operating system, he avoided having to design electronics from scratch, focusing instead on mechanical integration, ergonomics, and software. For anyone considering a DIY car display mod, this project is a powerful reminder that your next dashboard upgrade might already be sitting in a drawer.
Designing and 3D Printing the Gear Knob Housing
The heart of the build is a 3D printed gear knob designed to cradle the circular smartwatch display while still fitting comfortably in the driver’s hand. Desmontei modelled a shell that routes the watch’s internals into the center of the knob and allows wiring and mounting hardware to pass through the gear lever. The 3D printed gear knob had to balance aesthetics, wall thickness, and durability so it could survive daily shifts and vibrations. Community feedback has already inspired ideas for a second version using stronger printing methods such as SLS for improved toughness and precision. This mechanical side of the smartwatch upcycling project is as important as the software: without a secure, well-shaped housing, even the smartest Wear OS smartwatch hack would feel unsafe or awkward to use in a moving car.
How the Watch Knows Which Gear You Are In
Instead of tapping into the car’s electronics, Desmontei wrote a custom Wear OS app that infers the active gear from motion data. He “vibe-coded” the app to read accelerometer and gyroscope sensors, then calculates the knob’s angle relative to a known neutral position. Each gear corresponds to a distinct orientation, so the display can show the selected gear in real time. Early on, the algorithm struggled with inclines, sometimes misreporting gears on hills because the entire car is tilted. By fine-tuning the calculations and filtering the sensor data, he greatly improved accuracy. For a future version, he is considering adding a second reference sensor in the car to help correct for slopes. This clever software approach keeps the DIY car display mod non-invasive and reversible, avoiding taps into factory wiring while still providing useful, live feedback.
Adding Media Controls and Extra Functionality
Desmontei anticipated the question: who actually watches their gear lever while driving? To make the build more practical, he turned the knob into a media controller as well. The Wear OS app supports swipe gestures on the round display, letting the driver skip tracks or pause and play Spotify without reaching for the head unit or phone. This dual-purpose interface makes the DIY car display mod more than a gimmick, blending basic telemetry with everyday convenience. Because it runs on Wear OS, the interface can be expanded with additional screens or data in the future. In essence, the project shows how a Wear OS smartwatch hack can bridge automotive customization and wearable tech, transforming a single old watch into a flexible, upgradeable in-car control surface.
What This Project Teaches Future Makers
Beyond the cool factor, this smartwatch upcycling project highlights a repeatable process makers can adapt to their own builds. Step one is identifying unused tech with useful sensors and a screen; step two is designing a 3D printed enclosure that fits a new environment, whether that is a gear knob, dashboard mount, or steering wheel hub. Step three is lightweight, purpose-built software that exploits existing hardware capabilities such as motion sensing and touch. Desmontei’s experiment proves you do not need automotive-grade components to prototype compelling interfaces, just creativity and iterative testing. As he explores tougher materials and additional sensors for version two, other enthusiasts can borrow his ideas for their own 3D printed gear knob, center-console widgets, or even motorcycle and bike displays. It is a reminder that hacking, printing, and upcycling can push car interiors far beyond stock options.