EMERGENCY Mode
Edit on GitHubContinuous max-power SOS: activation, behavior, flag persistence and how to clear it
EMERGENCY Mode
Overview
EMERGENCY is the last-resort mode: continuous transmission at maximum power with no deep sleep. It is deliberately hard to stop accidentally - the flag survives reboots and power cycles so a crash or battery swap does not silence the beacon.
Activation
| Method | How |
|---|---|
| Hardware | Hold SW_MODE for >= 2 s |
| Dashboard | Emergency button (POST /emergency) |
| Auto | Optional low-battery auto-switch (aswitch) |
What It Does
- TX at maximum power (+22 dBm RadioLib; up to +30 dBm on the E22 PA).
- Payload repeated 3x per frequency.
- Full payload always: name + GPS when enabled.
- No deep sleep: continuous transmission.
- OLED: full-screen alternating inverse
SOS+ frequency + coordinates. - Audio: continuous 1760 Hz tone.
Battery Reality
| Cell | Expected runtime |
|---|---|
| 2000 mAh, GPS on | ~12 hours |
| 3000 mAh, GPS on | ~18 hours |
This is why EMERGENCY is for the acute phase, not for a multi-day wait. BEACON mode with a long sleep interval lasts days; EMERGENCY lasts hours.
Flag Persistence
The emergency flag (g_emergencyActive) lives in RTC RAM:
- It survives deep sleep, reboots and power cycles.
- A battery swap does not stop the transmission.
- Only CONFIG mode + save, or a factory reset, clears it.
Warning
If you are testing EMERGENCY mode, expect the device to keep transmitting after you power-cycle it. Clear it deliberately via CONFIG mode - this is the designed failsafe, not a bug.