AudioMoth Troubleshooting flowchart

AudioMoth & HydroMoth

Troubleshooting flowchart

Tell us the switch position and what the two LEDs are doing, and we'll tell you what it means and what (if anything) to do about it. Based on Open Acoustic Devices' own LED and setup guides - see the full reference below.

1 · Switch position

Diagnosis

Select a switch position, then what the LEDs are doing.

The two AudioMoth/HydroMoth LEDs (green and red, on the side of the device) mean different things depending on the switch position - this walks through them step by step instead of one long reference table.

Good to know

  • Most LED problems trace back to the SD card or the battery - check those two first.
  • If nothing lights up at all, in any switch position, suspect dead or incorrectly-inserted batteries before anything else.
  • Prefer scanning a table? The full official reference is below.
Full LED & battery reference

Switch set to CUSTOM

Single green flash every 2 seconds, red offSleeping between recordings - normal idle state.
Single red flash, flickeringRecording in progress - flash rate depends on sample rate.
Green solid, red flashing (100ms)Getting a GPS time fix, 5 minutes before a recording period - only if GPS time-setting is enabled.
Both LEDs flashing (100ms) on first switching to CUSTOMNo recording schedule has been set.
A single LED flashes (10ms) every 4 secondsWaiting for the magnetic switch to trigger - only if delayed start is enabled.
Both LEDs, one long flash (500ms)A recording failed and was cut short - SD card write error or low battery.
Both LEDs, short flashes (10ms) between recordingsAn earlier scheduled recording was cut short, same causes as above.
Nothing at allNot an official LED code - usually no power reaching the device (check batteries first), occasionally missing firmware from the factory.

Switch set to DEFAULT

Single red flash, flickeringRecording in progress, writing to the SD card.
Red solid, green flashing (100ms)Listening for the acoustic chime from the AudioMoth Chime app, to set the clock.
Green solid for ~2 seconds, then offChime accepted - the schedule begins right after.
Both LEDs, one long flash (500ms)Recording failure - if immediate on switching to DEFAULT, check the SD card is seated correctly.
Nothing at allNot an official LED code - usually no power reaching the device, occasionally missing firmware from the factory.

Switch set to USB / OFF

Green solid, red offConnected to USB and powered.
Red flashes a number of times, then stopsBattery level check, read right when switching to USB/OFF - see the tables below.
Nothing at all, not recognized by a computerNot an official LED code - usually no power, a bad cable, or a bad port; occasionally missing firmware from the factory.

Battery level flash count (switch to USB/OFF)

There are two scales, selected by "Use NiMH/LiPo voltage range for battery level indication" in the Configuration App.

Alkaline (default) Voltage
4 flashes ≥ 4.6 V
3 flashes 4.4–4.5 V
2 flashes 4.0–4.3 V
1 flash 3.6–3.9 V
10 rapid flashes ≤ 3.5 V
NiMH / LiPo Voltage
1 flash ≥ 4.3 V
2 flashes 4.2 V
3 flashes 4.1 V
4 flashes 4.0 V
5 flashes 3.9 V
6 flashes 3.8 V
7 flashes 3.7 V
8 flashes 3.6 V
10 rapid flashes ≤ 3.5 V

Source

Reproduced from Open Acoustic Devices' own LED guide and setup guide. The "nothing lights up at all" entries aren't part of either official guide - they're included here as the most common real-world cause when there's no LED activity whatsoever. If your device is doing something not covered here, the OAD support forum is the next place to check.

Reproduces Open Acoustic Devices' official LED behavior. Always double-check against openacousticdevices.info for the latest firmware.

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