greetings! has there been an attempt to stream the audio / bytes data over USB back to a host machine? This would be instead of writing to the SD. I understand if the paperclip is in, the device shows up as a tty serial device. Can we read the serial out from this by modifying the firmware?
https://github.com/OpenAcousticDevices/AudioMoth-Firmware-Basic/blob/master/main.c#L620
We're trying out a few ideas to implement this. One option that looks feasible is to implement a USB microphone protocol so that you can record at any sample rate up to 384kHz using exactly the same gain and filters that the normal AudioMoth front-end uses.
Hi Ian, I am also interested in this use case. Were you ever able to get something working? Our goal is to use the AudioMoth as a cheap sensor that can stream data over usb to our hub which does on device ML.
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.
Ian
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