Calyx
Android microphones vary significantly in sensitivity across devices, making it hard to choose a sensible default gain for an app like Hertz & Health. The app includes a manual calibration feature, but accurate calibration requires equipment most users don't have.
I built Calyx — a crowdsourced calibration database built to solve this. Users who have calibrated their microphones can submit their data, and anyone with a similar device can pull that data directly into the app instead of calibrating from scratch.
The Calyx API is currently only accessible to the Hertz & Health app while essential security features are still in development. The API is hosted on Render's free tier — expect an initial delay of around 30 seconds on the first request.
Once the API is open to the public, documentation will be published separately and linked here.