We would like to use the Audiomoth as a recording platform for adapting some ultrasound microphones to it (the Bufo or Myotis from our Sonitor system) to get low-noise recordings.
I would like to know whether in principle, it is possible to de-solder the built-in microphone (or install a switch, simply) to connect another microphone (like the Knowles SPU0410LR5H-QB or Vesper''s VM1000) to the PCB even though those microphones' native sensitivity would be much lower than the built-in microphone's, around -38 dB.
Are the pre-amps on the Audiomoth strong enough to boost the signal to an acceptable level? If it worked, we would be keen to show that the Audiomoth can be expanded with this open-source mic system. We would like to show that in an upcoming new version of our aforementioned article for which we would be glad to get new collaborators involved.
I got SPU0410LR5H-QB connected to an external mic plug for electret of mics of a Raspberry PI audio card. I used scheme from Figure 26 from SiSonic Design Guide /https://www.knowles.com/docs/default-source/default-document-library/sisonic-design-guide.pdf . There were other schemes which I haven't tested or compared yet. I do not have currently latest version of AudioMoth with external mic plug, so I cannot test. But probably this wiring would work also with AudioMoth.
Hi Olli,
That is exactly the point 😊
We are planning to test the first boards next week. The boards will be circular 10mm (same size as electret) and prepared for selectable 2 or 3 wire connection.
Would be nice to hear more about that circuit, thanks. I do have one SPU0410LR5H-QB and just noticed that it does not work if you put it to a plug reserved for an electret mic.
I found a document https://invensense.tdk.com/wp-content/uploads/2015/02/Using-a-MEMS-Microphone-in-a-2-Wire-Microphone-Circuit.pdf which describes a conversion circuit for another MEMS model - maybe this is something to try.
We are working on a plug and play compatible circuit with a Knowles SPU0410LR5H-QB, does anyone have interest in such a board?
Thomas, you should contact me on my email. I have been working on that same project for a couple of years and have some insight I could share. Halmitchell@gmail.com
Thank you very much Hall for the response. I will order the latest version of the audiomoth and I will test with my microphones (EM172). I think it's worth it. My olympus LS11 and my sony PCM M10 give excellent results with the EM172. My idea is to be able to connect my parabolic dish to the Audiomoth to carry out night migration monitoring.
Thomas