Khutwa
A native Android activity tracker built around sensor accuracy and complete data privacy.
The problem
Step counters disagree with each other and with themselves. Totals drift when the application is killed, and daily history stops reconciling with the live sensor. Most applications hide the discrepancy rather than resolve it.
Approach
Two sensors with separated responsibilities: the hardware counter is the sole authority on totals and survives process death, while the detector supplies the timing data that drives cadence and activity classification.
One invariant is held and checked: stored daily totals must sum to exactly the live counter. It is verified on device and exposed as a diagnostic anyone can re-run.
No advertising, no analytics, no telemetry. Exactly one file in the codebase opens a network socket, and it fetches map tiles.
Currently a debug-signed build with Arabic-only strings. Release signing and store listing remain outstanding — packaging work, not new engineering.