Recording failure: empty SD card and red/green LED
I ran into an issue during one of my AudioMoth deployments where the recorder did not make any recordings.
The AudioMoth was configured in CUSTOM mode with a recording schedule from 18:00 to 06:00. The same AudioMoth and the same schedule had worked correctly during the previous deployment week. I did not change the CUSTOM switch position between deployments.
For this deployment, I used a new SanDisk Outdoors FHD 64 GB microSD card, the same type of card that I had successfully used before. The batteries were also replaced before deployment.
After retrieving the AudioMoth, the SD card was completely empty and contained no WAV files or summary files. I also observed a red and green LED on the device, which seems similar to other reported cases of recording failure or SD card write errors.
Based on the LED behaviour and the empty SD card, I suspect this may have been caused by an SD card write or initialization error, a battery/contact issue, or possibly an issue with the AudioMoth or SD-card slot.
Could you advise what the most likely cause might be, and what diagnostics I should run to determine whether the problem was caused by the SD card, the batteries/contact, or the AudioMoth itself?
Thank you in advance for your help.
Hi,
The blank SD card is almost certainly caused by the AudioMoth waiting for the acoustic chime and never actually starting the recording sequence. It would have been showing a constant red LED and a flashing green LED. The safest sequence is to switch back to USB/OFF so that if the AudioMoth is recording it can close the current file. Change the SD card and change the batteries. The AudioMoth will then have lost the time but still retained the configuration which is permanently stored in the microcontroller. To set the time you can either use the Time App on your laptop and connect via USB. This will update the time and leave the configuration unchanged. Once the time is set, switch to CUSTOM and the AudioMoth either immediately start a recording (depending on the schedule) or wait for the next recording showing a flashing green LED every two seconds. Altenatively, switch to CUSTOM immediately and the AudioMoth will start listening for the acoustic chime whilst showing a constant red LED and a flashing green LED. Play the chime from the AudioMoth. You can try repeatedly as it takes a couple of goes to get the volume and distance correct. If the time is correctly received, the green LED will light for a couple of seconds, and then the schedule will start as above.
You can also set a location with the acoustic chime and this will be added to the GUANO metadata in each WAV file. Alex