Reverse-engineered Bluetooth Low Energy protocol documentation for the Wellue O2Ring pulse oximeter

Reverse-engineered BLE protocol reference for the Wellue O2Ring-S (T8520), with a working Python reference implementation.

Command-line analyzer for Wellue O2Ring overnight pulse-oximetry CSV exports: SpO2 statistics, ODI (3%/4%), desaturation events, nadir, and CSV/JSON/Excel reports. Supported by Night Time Comfort.

Local-first physiological analyzers — oximetry, HRV, CGM, ECG . No network, no CDNs, no accounts.