discussion / Acoustics  / 21 August 2019

Microphone for bird monitoring on Raspberry Pi

Hi,

I am building a system to monitor birds (i.e. ~50-20k Hz) using a Raspberry Pi and I am looking for the best option for the microphone. I am considering:

- a USB microphone with integrated DAC, such as the Dodotronic Ultramic UM192K, but it is expensive (200€) and I don't need ultrasonic frequencies.

- a sound card, such as the Sound Blaster PLAY! 3 or the Ugreen sound card with a "standard" microphone with 3.5mm plug. I found recommendations for the Primo EM172 microphone (there is a recent thread here about it), but it has an electret capsule and needs to be powered and I cannot find any cheap sound cards with plugin power. I have been said that it works anyway but I am not sure about the sensitivity and SNR...

- MEMS microphone, such as the Invensense ICS-40720 (recommended in this paper), or the Knowles SPM0408LE5H-TB-6 used in the famous Audiomoth, but it requires some hardware development I am not skilled at.

Has anybody any advice on some not-too-complicated configuration that would provide good sound quality and sensitivity?

Thank you !




I can confirm the SoundBlaster Play! 3 works well with the Clippy EM172 mono microphone. Most consumer sound cards will provide the bias voltage for an electret mic. The SB play3 provides around 3V from memory, which is adequate for the Primo 173, although they do apparently work better at higher (5v?) voltages. I too spent a lot of time looking at different options, but this combo seems to be readily available and a reasonable price at the moment.

I can understand the reluctance to go down the I2c route on linux, but I bought some Adafruit MEMs mics (https://www.adafruit.com/product/3421) and they work fine.

If you want to dip a toe in the water, are not too cost concious, but want something you just plug in and it (largely) pretty much works, then I'd recommend looking at the seeed respeaker. Its an array, and is probably overkill for what you want. It does come with quite a bit of hand holding though, I got a "4 mic linear". Connect some jumper wires, screw on a board, install some software (!). OK for a POC (proof of concept) and as a sanity check.

Going back to the Adafruits mems breakouts, I have them wired back to the pi by re-using old CAT5 network cable, so the pi can be in one place and the mics somewhat remote - eg round the other side of a tree?  I configured a lot of software to get this working as I wanted, but it essentially removes "white noise", does file compression etc.