Hello Anton, Yes, you can remove the battery holder easily. First, you need to separate the hot glue holding the battery holder and board together. I use a heat gun aimed between board and battery holder and gently separate the two opposite the where the battery holder posts connect to board. The glue will melt and you can separate them. I use a small piece of cardboad to slide through to keep the glue from connecting back together. I then use a solder iron to heat the solder on one of the battery holder connection pads and gently lift the board to separate from battery holder. Then I do the same on the other pad. Sometimes you have to alternate sides once or twice until they are completely apart. I've done this on many audiomoths and not had a problem. You can also just get the dev board if you don't want to go through the trouble but they are a little more expensive. Shawn

I've found a waterproof electret omnidirectional microphone I would like to try with the AudioMoth 1.2.0 - https://www.digikey.com/en/products/detail/cui-devices/CME-1538-100LB/2364631. It comes with leads (ground & signal), but in the application note it says, "The jack detect must be pulled low to enable the external microphone." Am I correct to solder a jumper to ground from the jack detect to permanently activate the external microphone? I'd also appreciate any thoughts on this microphone if anyone has any. Thanks.

Wow! Your's it at such a higher frequency. Of course I'm not even recording that high so maybe it's there? I've read elsewhere that it is most likely the board writing to the SD card. But it doesn't seem like that would be occurring at different frequencies. Hopefully something that gets solved in future versions.

Further testing with a larger hole drilled (~5mm) and a piece of scotch tape over the hole and then cellophane show only very faint evidence of clicking noises. I'm going to say the acoustic membrane I got from China isn't so "acoustic" friendly. I've found a better quality product, hopefully, and will drill a slightly larger hole (~7-8mm) to try. Here's a screenshot using the scotch tape over the hole.

@andya Interesting. I was thinking to countersink from the inside. But I also see you are using the wire mesh/nikwax and not the acoustic membranes. Hmmm....Thanks for your feedback.

Hello Emil, Have you noticed a "clicking" sound on your recordings at lower frequencies (~5-30kHz) with the AudioMoth inside the case? See here for why I ask - https://www.openacousticdevices.info/support/main/comment/5dce2a2732c0dc00170ca837

@Kees Polderman Thanks for your reply. What size hole did you drill in the cover for the mic? Mine is 3mm. I am wondering if a larger hole and larger membrane might help.

Updated testing - I removed the acoustic membrane and the "click" is almost unrecognizable.

Have you noticed a "clicking" sound on your recordings at lower frequencies (~5-30kHz) with the AudioMoth inside the case? See here for why I ask - https://www.openacousticdevices.info/support/main/comment/5dce2a2732c0dc00170ca837

Have you noticed a "clicking" sound on your recordings at lower frequencies (~5-30kHz) with the AudioMoth inside the case? See here for why I ask - https://www.openacousticdevices.info/support/main/comment/5dce2a2732c0dc00170ca837

Have you noticed a "clicking" sound on your recordings at lower frequencies (~5-30kHz) with the AudioMoth inside the case? See here for why I ask - https://www.openacousticdevices.info/support/main/comment/5dce2a2732c0dc00170ca837

I am having a similar "clicking" problem at a different frequency (5-8kHz, 6.5-10kHZ). I have identified it has to do with the cover of my case. Why? What can I do? I have used a waterproof junction box similar to what others have posted. I've removed the battery tray and soldered dual JST connectors onto the board. I am using a 3.7v 4400mah Lion battery. Voltage for these test was at 4.2v. Settings were 48kHz with medium gain. Firmware 1.2.2. Sandisk Extreme 128GB. Our focus is primates and birds. Is this going to make life miserable when it comes to using software to sort/identify vocalizations? Here is what I get with everything closed up. Here is what I get with board still mounted to cover but separated from box with battery. Notice frequency change. Here is what I get with board removed from cover. Nice and clean.

@Peter Prince Thank you! Will have to play with "low battery cut-off" to test the runtime difference with and without.

I'm also interested in more information about these options. Would be nice to know what they do.