Runn Diagnostics App

I own an NPE Runn sensor and it’s quite neat. It's this little matte black sensor that sits to the left or right of your treadmill belt and broadcasts data over Bluetooth. It just works and gives more accurate running data than my watch.

The sensor does not have a native app to show your current run, so I built an app, and it’s called: Runn Diagnostics. The app connects directly to the sensor using the Web Bluetooth API and displays what the hardware is broadcasting: Pace in km or mi, cadence, incline as a percentage and distance etc. All of it, straight from BLE, rendered in real time. It reads from two Bluetooth services simultaneously: FTMS and RSC.

There’s also a raw data console at the bottom of the screen. It's a scrolling log of every single BLE notification as it arrives, decoded and timestamped. You can watch the bytes come in and see exactly what the sensor is reporting.

Preview with a simulation

Flip the simulation toggle, and the app generates synthetic BLE data that mimics a real treadmill session. Speed ramps up and down, cadence varies and incline changes. Everything behaves like a real sensor connection, except there's no hardware involved.

A browser tab is all you need

There's no app to install. No dependencies. You open the URL (https://labs.hellowiseman.com/runn-sensor-diagnostics) in a Bluetooth-capable browser, click "Connect Runn Sensor," and it pairs directly with your hardware. If you’re using an iPhone or iPad then you should install a BLE browser like Bluefy (it’s free).

I think there's something satisfying about a tool that does one thing well and doesn't ask you to create an account to use it. Sometimes the most useful thing you can build is just a clearer window into what's already happening. That’s really the driving goal behind the little app projects I’m building over on my labs website. Keeping things simple, functional, and accessible.