Audi Enthusiasts Transforms Old Smartwatch Into Custom Digital Gear Shift Display

An enterprising Audi enthusiast has transformed his 2001 A4's manual gear shift into a sophisticated digital display by repurposing an old smartwatch in a custom 3D-printed housing. The project, showcased by Reddit user Desmontei, represents a creative fusion of automotive customization, electronics hacking, and software development.

The modification began with Desmontei extracting the OLED screen and motherboard from a TicWatch Pro 3 smartwatch. "I took an old TicWatch Pro 3 smartwatch and carefully cut the original casing with a rotary tool to extract just the OLED screen and motherboard," explained the DIYer. "Then, I modeled a custom shift knob enclosure to house the electronics perfectly."

Technical Implementation

The heart of the project lies in the custom WearOS application developed using vibe code. The app serves two primary functions: displaying the current gear selection and providing media control capabilities. The gear detection mechanism relies on the smartwatch's built-in accelerometer and gyroscope to determine the angle of the gear stick.

"The watch face was secured to the gear stick very carefully, using a 3D-printed mount with tight tolerances," Desmontei noted. "The video shared in my Reddit post shows the smartwatch display changing to match the current gear stick selection."

However, implementing reliable gear detection presented significant challenges. The inertial measurement unit (IMU) data can be thrown off when driving uphill or downhill, causing incorrect gear readings. To address this, Desmontei implemented dynamic calibration algorithms that continuously adjust for these environmental factors.

Media Control Integration

Beyond its primary function as a gear indicator, the repurposed smartwatch doubles as an intuitive media controller. Drivers can control Spotify playback through intuitive swipe gestures on the screen—swiping left or right to change tracks, and tapping to pause or resume playback.

This integration enhances the driving experience by allowing drivers to keep their hands on the wheel while maintaining control of their entertainment system. The touchscreen interface provides visual feedback that's more responsive than traditional steering wheel controls.

Power and Installation

The installation represents a clean, integrated solution that bypasses the smartwatch's original battery system. Instead, the modified device is wired directly to the car's 12V electrical system, ensuring consistent power without worrying about battery life or charging.

The 3D-printed housing was designed with extremely tight tolerances to prevent the screen from popping out during gear shifting. "I didn't want the screen popping out while shifting gears, and PLA was the easiest to test the fitment," Desmontei explained. Future iterations may switch to more durable materials like ABS or PETG if the prototype warps or breaks over time.

Future Enhancements

Desmontei has already outlined plans for "Phase 2" of the project, which will significantly expand the functionality of the custom gear shift. The next iteration will integrate with an OBD2 scanner via Tasker to display live telemetry data including RPM and engine temperature.

Another potential improvement involves adding a secondary reference gyroscope sensor within the car itself. This would provide more reliable gear shift position calculations by compensating for the vehicle's overall movement, addressing the current limitations of relying solely on the IMU data from the gear stick.

The DIY Spirit

This project exemplifies the growing trend of automotive enthusiasts leveraging modern technology to enhance classic vehicles. By combining 3D printing, hardware modification, and custom software development, Desmontei has created a solution that's both functional and impressive.

For those interested in attempting a similar project, Desmontei has documented the entire process in a detailed two-hour video available on their YouTube channel. The walkthrough covers everything from extracting the smartwatch components to programming the WearOS application and integrating everything into the vehicle.

Desmontei's other automotive and electronics modifications include PlayStation and handheld console projects, demonstrating a broad range of technical skills applied to creative endeavors. This smartwatch gear shift represents particularly innovative thinking in automotive customization, showing how existing consumer electronics can be repurposed to enhance classic vehicles with modern functionality.

The project highlights the intersection of automotive enthusiasm and technological innovation, proving that with creativity and technical skill, even the most mundane components of a vehicle can be transformed into sophisticated, interactive interfaces.