Calibration

Save mic positions + TDOA offsets as a named preset. Load applies both without touching the chirp marker — re-cal via Start Listening when needed.

— select a preset — Load Save as… Delete

Click map to add a mic at that location. Right-click a marker to remove it. Drag to reposition. The crosshair marks your station centre.

Save to Pi Reload from Pi

1. Click the map to place a chirp marker (yellow) where you will stand.
2. Click Start Listening — sentinel will collect raw TDOA lags for 30 seconds.
3. Open chirp.html on your phone (set volume to max) and either:
   • tap Play Test Pattern once at the start of the window — 5 s log sweep, one unambiguous arrival per mic, immune to USB processing offsets. Best results.
   • or tap Play Chirp 5–10 times — works but vulnerable to per-mic timing offsets larger than 20 ms.
Detection is matched-filter only — claps and other transients are ignored.
4. Sentinel computes per-pair offsets from expected vs measured delays and saves to config.ini.

Place Chirp Location No chirp position set

Start Listening (30s)