We have a grant to deploy ~30 AMs at a temparate forest (severe winters/mild summers) to record continuously at 8KHz ambient sounds with emphasis on human activities.The goal is to promote the use of passive acoustic monitoring as a law enforcement monitoring tool for protected area managers, so it is critical that the tool is reliable and logistically "affordable" to operate (hence why we are looking at ideally a 3 month deployment time). We have successfully done that in Afrotropical settings using Wildlife Acoustic sensors/Cornell SWIFT sensors. I am considering using Audio Moths as I like their energy consumption, size, cost and ethos of the project.
My concern is whether the AM is, in its current stage of development (i.e. 1.0.0 or 1.1.0), able to be deployed for 3 months. Specifically:
a) Three months * ~1.3Gb data/day requires a 128Gb card. I understand that if formatted in FAT32 using specific software, the AM can handle such a card, right? Any issues from people who have tried such size cards?
b) Batteries - I read in one forum post reply by Andy about the Belize project that with a 6V lantern batterry (24Ah + specific energy consumption set up) the AMs operated for 400 days. Oyr sensors have to record continuously. Has anyone used such size batteries for continuous recording who can share info on recording times achieved?
c) Casing - given the battery size required, I can not use the neat/tidy small-size options that have been kindly shared in relevant forums. We can make our own casings I suppose from boxes for external electrical cabling etc. but I wonder whether anyone has successfully used for long deployments a case that can house such a large battery. I am aware of the Belize project case (PVC pipe) that the AM team has used, but that design is not available to order etc. just yet, right?
d) Microphone cover - I understand that due to humidity there should be a fine wire screen mesh added at the bottom of the case (possibly over the microphone opening?) to let humidity out during the day. Have there been any issues with that? Has anyone used such wire screens with the AM (i.e. only screens without water proof membrane that apparently reduces - possibly significantly - the detection range of sounds)?
e) Reliability issues - We have experiemented with 2 AMs already and occasionally the recorders did not record as expected (i.e. did not start, lost scheduling etc.). I am sure most of that is due to our handling or shaky batteries. Can someone comment on the reliability of continuous recording of the AM for >1+ deployments in temperate settings?
The budget and project schedule is such that we basically have one shot at making this work. We will not be able to afford reverting to other sensors if the AMs do not work, and we really want to make people love passive acoustic monitoring and its potential. Hence, my post title. Is the AM - in the community's opinion - fit for purpose?
I value the communtiy's collective feedback and look forward to reading it.