©2019 Open Acoustic Devices

Aug 15

stream data over USB


Hi, Technically it's possible; you can make the firmware implement any USB protocol you like. However, there would probably be easier ways to achieve it than starting with AudioMoth. If you wanted to build a device for this there are dedicated Audio codec chips intended for building USB headsets that will do all the audio / USB work for you - https://www.digikey.co.uk/product-detail/en/texas-instruments/PCM2912APJTR/296-39145-1-ND/5143156. There are a few Raspberry Pi based audio collection devices that use a USB microphone adaptor (that probably use the chips above or something like them internally) to provide audio - https://besjournals.onlinelibrary.wiley.com/doi/10.1111/2041-210X.12678 . These have the advantage that you can program the Raspberry Pi in a high level language such as Python but they will use a lot more power than AudioMoth and need much bigger batteries. Alex

Aug 30

Hi Mugsey, Did you pursue this technique to stream data over USB? I'd be interested in working with you to modify the firmware and get the data to be streamed. Let me know if you have an interest.


I'm planning on keeping the SD card to store the data locally, then intermittently reading from the SD card, after the file is written. This way, if the Raspberry PI runs out of power, and batteries are installed in the AudioMoth, the unit will continue to record per the schedule.


I appreciate that there are other devices which can perform this simpler, however the device signal to noise ratio and ultrasonic recording capabilities make this a superior alternative currently in my opinion.


New Posts
  • Hi, I have purchased an AudioMoth to detect the ultrasonic sound emitted by bats. And I would like to know how can I detect i) count number of bats ii) bats' flying direction. I am doing a project to contextualize bat data through different actuators of Arduino. Using LEDs, speakers, motors, etc to visualize bat data. For example, if frequency = 45kHz, LED will light up; if more bats, the motor will spin faster, etc. How can I do that? And can I transfer the data live, and wireless, using a raspberry pi and upload it to the cloud? Again, how can I achieve that? Finally, is there any guide to manipulating the bat ultrasonic wav. file to human audible sound or visualize through spectrogram? Any tutorial for that? I am trying to use Adobe Audition. Many Thanks!
  • Hello, we deployed AMs with 64GB cards (formatted to FAT32 with a Mac) and 3 x eneloop 1900mAh AA batteries. Calculated they should last ~8-9 weeks at our recording schedule. Have just found that the first 8 we retrieved all ceased recording within a day of each other, 4 weeks after deployment. The cards only have 19GB of data each, so probably not a card issue. Individual testing of AA batteries pre- and post-deployment showed average voltage of 1.34 each prior, and now each AM had at least one battery with voltage as low as 0.06-0.21V (but others up to 1.14V). Stumped, as a colleague had the same set- up with a slightly longer daily recording schedule and longer deployment, with no issues. Am I right in thinking: 1) there is some critical minimum threshold in battery voltage, below which the AMs won’t work, despite our calculations they should have lasted twice as long? 2) if we decrease the amount of data collected per day they would last longer, and 3) does ticking or unticking the ‘enable low battery cut-off’ box in the configuration app make any difference to this? 4) is there a large error around the mAh drawdown prediction on the app that could explain our predicted vs actual data collection period?
  • Hi, in all my recordings there's a "clicking" noise (26-28kHz). This is an issue that I had before with some recordings but now the noise is louder and it is present in all recordings. The batteries are Energizer AA (new) and the SD card is the SanDisk Extreme 32GB. Is there Anything I can do to make the "clicking" noise disappear?
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