Record gets split at midnight and doesn't continue second half

Hi Bas, It sounds like the battery is running low and that the files have been corrupted because of this. We've added a software check for this in the next version of the firmware to be released in a couple of weeks which will stop recordings safely when this happens.

You can check the header information in a number of different ways. On a Mac the 'Get Info' option will show you the information.

You can also read it in an audio editor such as Audacity.

Or just open the file as a text file and read it amongst the other header information.

If you email me your address (alex.rogers@cs.ox.ac.uk) I'll put a SD card in the post.

Hi Alex - So, I've tried a couple nights in a row now and at first it looked like it worked (putting a new SD card in the AudioMoth). But last night (and partly the night before) it only recorded files which were damaged or had a different file extention (the PC couldn't specify). The size of the files were 0 bytes. The only thing I noticed was that the battery level became below <3.6 V. Normally, it just specifies what the voltage is, but now it says "<...", so I'm going to try to replace the batteries and try for one more night.

I'm based in the Netherlands and I'm willing to send you the SD card so you can take a look at it. I have no idea how to find those battery levels in the header files of the recordings. I can send you one (or two) of the recordings if you want.

I'll let you know what happend after I replaced the batteries today.

Yes, sorry 1.2.0 is the up to date firmware. When you say one recording, that means just one 3595 second recording, not the full recording period. That's very strange. I've set an AudioMoth up here to try to reproduce it. One thing to try is to reformat the SD card. It seems very strange that it used to work and has now stopped. Has this occurred with one single SD card?

Hi Alex - I've updated the firmware to the current version 1.2.1. (although it shows 1.2.0 in the app) and used the settings as described in your first message (3595 seconds and then a 5 second sleep duration between recordings), but it still produces only one record and stops after that. Any idea?

Hi Alex - Thank you for the quick response. I'll try these settings for tonight; let's see if they'll work! Thanks again!

You should probably also update the firmware on the AudioMoth device to the latest version - current 1.2.1. The instructions are here - https://www.openacousticdevices.info/flashing

Or if you prefer the longer recordings, make both scheduled sessions six hours long and have a recording period of 6 * 60 * 60 - 5 = 21595 seconds long and a 5 second sleep period to handle the switchover at midnight.

Hi,

The calculation in the configuration tool seems to be incorrect - it should be generating two files. We'll look at that and fix it in the next release.

The issue with the missing recordings is probably because the recording period set is longer than total length of the scheduled period - 10 hours compared to 6 hours and 5 hours. It was probably working okay initially by stopping and immediate restarting the recording, but as the SD card filled up a bit and opening and closing files started to take a little longer, it was missing the start of the new recording.

We would normally recommend having a recording length of 3595 seconds (just less than one hour) and then a 5 second sleep duration between recordings. This means that it can handle delays from the SD card and you get a set of files that start at the same time each day which align with the requested scheduled periods. These settings should avoid the problem that you see and probably make handling the data easier.

Alex