μMoth (Round 2)
Open Acoustic Devices
μMoth (“micro-moth”) is the worlds smallest full-spectrum acoustic development board, based on AudioMoth and the Gecko processor range. Just like its namesake the moth, μMoth can listen at audible frequencies, well into ultrasonic frequencies. It measures just 25mm x 36mm and weighs 4 grams. It is capable of recording uncompressed audio to microSD card at rates from 8,000 to 384,000 samples per second. It also shares the same supporting software and firmware as AudioMoth.
This is the only place to get the amazing μMoth
One μMoth v1.1
Not available / campaign funded, end date: Sat, 06 Nov 2021 12:55:00 PDT
300.0 mm (0.98') Micro USB Cable
SanDisk Extreme® microSDHC™ UHS-I w/adapter- 64GB
Campaign discussion forums are intended for questions about the product such as specifications or to share ideas about applications. The campaign initiator or GroupGets may also send out important one-to-many updates on this channel. This is not the place for individual technical support inquiries. For help or questions about an order, please log a ticket here: Support
This board comes without a case but it will ship in a box ;)
Regarding compression, here's a thorough answer from OpenAcoustics: The AudioMoth doesn’t support any standard compressed format such as FLAC, SHORTEN or X3. We experimented with them and they ended up using more energy than they saved and the file size reduction was pretty small - only about 70% of the original - as the bit resolution of AudioMoth recordings is already less than many recorders.
However, all the models will work with the amplitude threshold recording mode in the standard firmware. This avoids writing sounds below a specified amplitude threshold and encodes the length of any skipped periods allowing the exact sample interval to be restored. For bats this typically yields really big file size savings of between 1 to 10% of the original size.
There isn’t a standard case for μMoth as we expect it to be used in a very wide range of settings with batteries chosen according to the deployment requirements. To date it has been deployed on an African wild dog within a custom housing. It can also be deployed in 35mm film canisters, and as with other AudioMoth models, in a plastic zip lock bag in mild conditions.
@ccabrera The MEMS mic on the μMoth has a sensitivity of -18 dBV/Pa, 63dBA SNR, and a frequency range of 10Hz to 192kHz. It can be used for bat monitoring, but it's hard to say what the distance would be since it will depend on many factors.
If you need to order via invoice, we can take a purchase order. Just reach out to our sales team ( https://groupgets.com/contact ). For small orders, we do prefer you to go through the campaign checkout.
As an avid Audiomoth user I've been hesitating over placing an order as this model appears to lurch over into the 'Electronics nerd' territory, what with the lack of a case and already attached battery pack. Q1: I've researched available battery packs that would do the job, but could you confirm whether a 3xAA battery pack (as with Audiomoth) would be sufficient or whether a 4xAA battery pack would be preferred. Q2: from looking at the circuit board photos, is the switch mechanism for moving between Default/USB/Custom different? (It appears different in the photo) . Q3: Where is the miicrophone on the board? Q4: How and where can one attach an external microphone and does this involve getting out a soldering iron? Q5: with a battery pack attached via a JST connector, would this not be likely to overlap the connections labelled a7, a8 on the board and would that be an issue?
Thanks for your detailed answer - just wish that I had received notification of your reply in time to place an order. I did revisit the page, but when I did, it appeared that my question had not been posted or made public. Guess I'll stick with what I know and order more Audiomoth units.
Written by: | November 15, 2021
Written by: GroupGets | November 08, 2021
Written by: GroupGets | November 04, 2021
Q1: I've researched available battery packs that would do the job, but could you confirm whether a 3xAA battery pack (as with Audiomoth) would be sufficient or whether a 4xAA battery pack would be preferred.
A: 3xAA battery pack would be sufficient, but it would require a JST-PH connector. Such this AA version from Digikey https://www.digikey.co.uk/en/products/detail/adafruit-industries-llc/3287/6569765
Or this AAA version
If other battery holders are to be used care must be taken to make sure the red and black wires are in the correct orientation. The wires can be swapped quite easily though.
Q2: from looking at the circuit board photos, is the switch mechanism for moving between Default/USB/Custom different? (It appears different in the photo) .
A: The switch mechanism requires a small flat head screw driver to function. This was designed to prevent inadvertently changing switch position during deployment.
Q3: Where is the microphone on the board?
On the microcontroller layer, the microphone is the grey rectangular component with a “K” on it. Its located above the “1.0.0" version number. On the microSD card side, its located underneath the microphone symbol.
Q4: How and where can one attach an external microphone and does this involve getting out a soldering iron?
You cannot attach an external microphone to uMoth version 1.0.0.
Q5: with a battery pack attached via a JST connector, would this not be likely to overlap the connections labelled a7, a8 on the board and would that be an issue?
The plug is at a right angle with wires positioned away from the PCB.
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