Can this device be modified to listen for underwater dynamiting?
So how did you bypass the microphone?
@Jamie Macaulay Based on this post by the same guy (https://www.openacousticdevices.info/support/device-support/use-audiomoth-underwater), it looks like he unsoldered the MEMS microphone and reconnected it. @qdxiatao Is that correct?
An Audiomoth could be a great form factor for underwater acoustics. Sample rates of 384kHz are fine for harbour porpoises (the highest frequency species (sort of)) and the form factor appears to be very user friendly. SoundTraps by OceanInstruments are ultra low power ~ $200 alternative open boarda, however, these require users to solder USB connectors and batteries so not quite as neat a solution. Do you reckon there's any chance that the next Audiomoth design could provide 3 pins which would allow a hydrophone to be connected (signal, return and 3.3V for pre-amplifier power)? Potting such a device with a SubConn connector for USB connection and a hydrophone could allow us to make inexpensive underwater recorders- something definitely needed in the marine mammal bio acoustics community.
@Jamie Macaulay i do a similar work.
Thank you for the update.
Sorry for the late reply.. It is not possible to add an external microphone or hydrophone to AudioMoth, the device comes with a fixed MEMS microphone.
Hello Robert, Only just placed an order for one so its going to be a few days/weeks before it turns up.
Initial thoughts are to keep the electronics dry in a U/W camera housing with a waterproof gland on the surface and sink a hydrophone under it. I've made my own hydrophones in the past but unsure of their bandwidth/sensitivity so it might need a preamp. Also I was thinking about 3D printing a case with a rubber seal slot. Much experimenting to be done.
Thanks, Phil. Did you find a suitable underwater case and a hydrophone?
I too am planning to use it for underwater monitoring. The best way would be to replace the microphone with a hydrophone and keep the Audiomoth dry. Cetaceans such as dolphins / porpoises produce sounds up to 140KHz, obviously dynamiting will produce a high energy shockwave with a frequency probably well under 200Hz, but it should be detectable even with the unit in a waterproof camera housing weighted down.
Sorry, I don't know anything about the frequencies. I live in the Philippines, where dynamiting the reef is common. I am trying to help out my friend, who setup a marine sanctuary.
If we are to use a submergible case, how will the microphone work? Does it need to protrude from the case?
Also, am I correct that information needs to downloaded from the card every once in a while?
I haven't seen this application tested with AudioMoth yet. Do you know the frequencies that these activities create? Also the device is not waterproof so you would need to develop a submergible case to test this out.