Short story: 3 functioning AMs, same configuration, brand new Intenso microSD cards U3, 64G. Problem with recordings. Two out of three collected no data --> cards not readable even though the laptop emitted the sound of recognition.
Long story for the patient ones....
I' ve been using 5-7 different AMs to record the changing activity of a cluster of bats in a big cave for a year. The firmware is 1.6.0 and the appropriate cases are used to protect them. The recordings take place once-twice per month and last few hours per day. The duration of each period of recordings is about 1-2 weeks). So, the AudioMoths have been used a lot of times and under different levels of humidity (anyways high in the cave). Some data have been lost, even if the steps made have been the same after months of practice. Technical problems are not clear in my head, just speculating. Sometimes the recording problems must have been due to extra high humidity in combination with low temperature. Also, I observed that most of the μSD cards started malfunctioning (not readable ususally) after certain time of uses....
I don' t know if the cards are to blame or if the AMs "get tired" after a certain number of uses.
At the moment the temperature is fine, in most of AMs I used brand new microSD cards. I really can not guess what's going wrong since the case is being used, temperature is fine and cards are new...
Has anybody any similar experience=a lot of efforts of recording, a lot of cards dying...??
Thank you very very much,
I recently had a similar experience with a Samsung EVO 128GB card. It was in one of three AMs I deployed for 10 days in a remote Alaska location. All three were in the molded waterproof case. The only one that failed had the Samsung EVO card. It was recognized by my computer for formatting and testing beforehand, When I brought it home no computer would recognize it in any way, not even to reformat it. I tried reading it with card adapters and USB readers. There is no obvious damage to either the card or the AM. The same AM will take and record on other cards.
Hi Maria, We haven't had reports of card becoming unreadable. SD cards are very variable in their energy consumption (https://www.openacousticdevices.info/sd-card-guide) and we generally recommend SanDisk Extreme cards. Most SD card turn are resolved by reformatting them regularly as their file allocation tables can get filled up from repeated writing and deleting of files. Sometimes people report AudioMoth that fail to write to the SD card (showing a flashing red and green LED) and this is generally due to corrosion or water damage on the AudioMoth PCB. Alex
Hi Maria, Have you been reformatting the SD card to exFAT after making a copy of the data?
Deleting files on previously used SD cards doesn't always leave the card in the best state.