RunBridge: Bluetooth Treadmill to Garmin Watch DIY Kit (Digital Download, Firmware & Guide)

Finally—your treadmill runs on your Garmin.

RunBridge is a small, clever bridge that lets your Assault Runner (or any FTMS Bluetooth treadmill) send speed and distance straight to your Garmin Fenix or Forerunner. No more guessing, no GPS drift—just accurate indoor run data on the watch you already use.

Perfect for runners who love their Garmin but train on an Assault Runner or other FTMS treadmill and want every session to count.

What you get

• RunBridge firmware (UF2 file) — ready to flash
• Step-by-step DIY flashing guide — put the board in bootloader mode, drag & drop the file, done
• Garmin setup instructions — add RunBridge as a Foot Pod, set speed/distance, start your run
• LED status guide — know at a glance if you’re connected to watch + treadmill
• Troubleshooting tips — common issues and fixes
• License — personal use on your own device (terms included)

Refer to https://RunBridge.dev for full documentation and compatibility guides.

Why RunBridge?

✓ Accurate — Uses the treadmill’s own speed and distance (no GPS, no guesswork)
✓ Reliable — Handles dropouts and reconnects; session distance stays correct
✓ Plug & play — Power from USB (treadmill port or power bank), then pair once with your watch
✓ Watch-first — Only talks to the treadmill when your Garmin is actually recording a run
✓ DIY in minutes — Flash with double-tap reset + copy the UF2 file; no Arduino needed

What you need (not included)

• Seeed Studio XIAO nRF52840 (standard BLE) — the tiny board that runs RunBridge
• USB-C cable — for power and flashing
• A Garmin watch that supports BLE Foot Pod (e.g. Fenix, Forerunner)
• An FTMS treadmill (Assault Runner, or other FTMS-compatible treadmills)

How it works

Flash the UF2 file onto your XIAO nRF52840 (full instructions included).
Power RunBridge with USB; add it on your Garmin as a Foot Pod named RunBridge.
Start an Indoor Run on your watch. RunBridge connects to the treadmill and streams speed and distance to your watch.
Run as usual—your Garmin records pace, distance, and time from the treadmill.
Compatibility

• Treadmills: Assault Runner and any treadmill that supports FTMS over Bluetooth
• Watches: Garmin watches that support BLE Running Speed & Cadence (e.g. Fenix 6/7, Forerunner 945/955/965, and many others)
• Hardware: Seeed Studio XIAO nRF52840 (non-Sense, standard BLE version)

Digital delivery

This is a digital product. After purchase you’ll receive a link to download the firmware (UF2) and the flashing guide. No physical item is shipped. You source the XIAO board and cable yourself for a true DIY setup.

License

The firmware is licensed for personal use on your own device. You may not resell, redistribute, or use it in products you sell. Full terms are in the included license file.

Questions? Convo me before or after purchase—happy to help you get running with RunBridge.