From Wristwear to Gear Lever: The Idea Behind the Mod
When DIY enthusiast Desmontei retired his TicWatch Pro 3, he didn’t shelve it—he embedded its brain into his car. Instead of leaving the smartwatch to gather dust, he stripped out the display and motherboard and designed a 3D printed gear knob around them, creating a fully functional smartwatch car mod. The result is a live, always-on gear indicator sitting right on the gear lever, merging automotive customization with wearable tech in a way that feels both futuristic and delightfully over-the-top. This project is more than a visual gimmick: it showcases how old electronics and modern fabrication tools can be combined to build a 3D printed gear knob that acts as a dynamic interface. For tinkerers, it’s a proof-of-concept showing just how far creative Wear OS repurposing can be pushed with some CAD work, a printer, and a bit of code.
How the Smartwatch Knows Which Gear You’re In
Instead of tapping into the car’s ECU, Desmontei leaned on the smartwatch’s built-in sensors. He “vibe-coded” a custom Wear OS app that reads accelerometer and gyroscope data to infer the angle of the gear lever. By mapping those angles to specific gear positions, the app dynamically displays the current gear on the watch screen embedded in the shifter. Early on, the system struggled with inclines, occasionally misreporting gears while driving on hills. By fine-tuning the algorithm and calibrating the angle thresholds, he managed to reduce these errors and make the DIY automotive display far more reliable. For a future version, Desmontei is considering adding a second sensor somewhere in the car as a reference point, allowing the system to factor out the car’s pitch and better distinguish gear position even when the entire vehicle is tilted.
3D Printing the Custom Gear Knob Housing
The hardware side of the build revolves around a carefully designed 3D printed gear knob that cradles the TicWatch Pro 3’s internals. Desmontei modeled the housing to snugly fit the circular display, route wiring, and mount securely on the existing gear lever. The print effectively turns what used to be a wrist-worn device into a structural component of the car’s interior. Community feedback on his Reddit post has already shaped plans for a second iteration: using a stronger printing method like SLS to improve durability and finish. This project is a strong demonstration of what 3D printing enables beyond small trinkets—here it becomes a custom, load-bearing automotive part. For makers exploring Wear OS repurposing, it highlights how rapid prototyping can translate digital designs into tangible, road-ready components tailored to very specific use cases.
Beyond Gears: Turning the Shifter Into a Media Controller
Even Desmontei admits that most drivers don’t stare at their gear lever while driving, so he gave the mod a second job: media control. The embedded smartwatch doubles as an in-car touch interface, letting the driver use swipe gestures to control Spotify playback. Swiping can skip tracks or pause the music, turning the 3D printed gear knob into a multifunctional DIY automotive display and controller. This dual-purpose approach is what makes the smartwatch car mod compelling: it’s not just a visual novelty, but a new interaction surface that’s already under your hand while you drive. It also underlines a broader lesson for makers—when hacking devices into new contexts, combining functional feedback (like gear position) with everyday controls (like music) is a powerful way to extract maximum value from otherwise obsolete hardware.
What This Project Says About the Future of DIY Car Tech
Desmontei’s smartwatch shifter is, on the surface, a fun party trick for car enthusiasts—but it points to larger trends in DIY tech. As consumer devices age out of updates or daily usefulness, projects like this show how Wear OS repurposing can give them a second life in unexpected places. Vibe coding makes it relatively straightforward to build custom apps that interpret sensor data in novel ways, while 3D printing provides the physical bridge that lets electronics inhabit new environments, from dashboards to gear levers. The mod also hints at a future where enthusiasts increasingly design their own interfaces rather than accepting whatever comes from the factory. Whether or not you want a watch in your shifter, this build stands as a clever blueprint for integrating old gadgets into bespoke, highly personalized automotive interiors.