HRBAbout
This app exists because two devices most cyclists already own will not speak to each other, and the accepted fix is to buy a third one.
Why this exists
An Apple Watch measures heart rate well, but it cannot send that reading to a trainer app or a bike computer. The watch reports to the iPhone, and the iPhone was never a heart rate sensor, so the standard advice is to buy a chest strap.
This app removes that purchase. The phone becomes the strap, and the equipment you already own is enough. It grew out of a Bluetooth trainer-control project — the half that controls a KICKR rather than feeding it — which will be published separately.
What it does
Your Apple Watch runs a workout session so it can read heart rate continuously. Each reading is sent to the iPhone, which re-broadcasts it over Bluetooth LE as a standard heart rate monitor — service 0x180D. Bike computers and training apps see the phone as an ordinary chest strap. AirPods Pro 3 can be a second source, and when both are running the app reconciles them into a single number before broadcasting.
There is no account, no analytics and no server. Nothing is uploaded anywhere, and nothing about you reaches the developer. The source is published under the MIT licence.
Three ways to get it
One app, one build. The two free routes ask for effort or patience instead of money; the App Store is the convenient one.
TestFlight — free, 90 days
Open to anyone, no invitation needed. Install Apple's TestFlight app and open the public link. Each build stays usable for 90 days from publication, and a new build resets the clock.
Sideload — free, needs a developer account
Every GitHub release carries a Release-configuration
.ipa, signed for distribution and therefore needing
re-signing with your own identity. HealthKit and background Bluetooth
are unavailable to free provisioning profiles, so this route needs a
paid Apple Developer account.
App Store — USD 4.99
One purchase, no subscription, no in-app purchase, no ads, no account. You are paying for the convenience of skipping both routes above, and for the work that went into it.
Credits
Published by atsignhandle llc. The drawing above was made by Google Gemini. Not affiliated with Apple, Wahoo, Dimond, Garmin, Zwift or MyWhoosh.