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Detect Migrating Birds with a Plastic Dish and a Cheap Microphone
- thatsadude 2y agoThat plastic dish (parabolic reflector) is not cheap.
- dyauspitr 2y agoHow about an amplifier connected directly into the Merlin bird app’s always listening mode. You don’t even have to review the files. You’ll just get a list of all the birds it has picked up. Birdnet is probably the same API Merlin uses.
- cjrp 2y agoI’d assume so, they’re both from Cornell’s Lab of Ornithology. The Merlin app is incredible; seeing the calls identified in realtime is magic.
- gizajob 2y agoWhy not keep all the electronics and sound card in the house and run a long XLR cable to the microphone? Battery and sound card and preamplifier outdoors to then run a USB cable out to it seems like a bit of a faff.
- kazinator 2y agoI suspect that though the author describes running a USB cable to the house, he may be preparing it for remote operation. (If you can count on it being next to a house where you can run a USB cable, you could also just power it off USB and skip the battery, right? So the battery must be designed in for a reason.) The mic is a condenser mic, so a pre-amp is needed, XLR or not. Cheap mics tend to be single-ended things without the balancing transformer or amplifier, so that would all be extra cost. XLR connectors and cables are more expensive. You'd want to go into some audio interface with XLR jacks which is also more expensive.
- gwern 2y ago'remote' also means you can set up networks of them to cover your area. Just dump a bucket every n meters, and spend a few hours driving around every few weeks to harvest the data & swap out batteries.
- hcfman 2y agoI developed a recorder project last year that make's this easier and you could deploy it on a Raspberry Pi zero and use a wifi link. https://github.com/hcfman/sbts-aru https://github.com/hcfman/sbts-aru It's using a cheap (0.40c) sound card, but personally I choose to have high quality mics (primo em272 mic capsules, used in high quality parabolic systems. However, there's nothing to stop you using < 10.00 euro microphones.
- hcfman 2y agoCheckout how good the primo mics are here for example: https://acousticnature.com/journal/how-to-make-diy-microphone-with-em172-272-capsules https://acousticnature.com/journal/how-to-make-diy-microphon...
- hcfman 2y agosbts-aru writes the files to an SD card so you don't need a whole running windows for this. Also, it passes all the audio through real time jackd, so while it's writing files you can also have an addition consumer running a real time matchin algorithm on it. If you use a Pi 4 or 5 you would be able to also do that at the same time on the same Pi as is recording.
- pvaldes 2y agoOr even better do it an isolated area to filter as much noise as possible
- contingencies 2y agoPoE works better (cheaper, higher bandwidth, differential signalling for higher EMI resistance, readily shared, etc.). Plastic covers are ~free (splash out and deploy duct tape if necessary). MEMS mic -> I2C -> cheap MCU -> ethernet. Theory: Capture digitally, and send the data - forget XLR and other expensive analog 'professional' fancabulation[0]. [0] https://www.youtube.com/watch?v=Ac7G7xOG2Ag https://www.youtube.com/watch?v=Ac7G7xOG2Ag
- jononor 2y agoI think you mean I2S (or PDM)? I2C is not common on MEMS microphones, as the bandwidth is generally insufficient for audio signals.
- contingencies 2y agoRight, I don't usually touch audio or video applications.
- hcfman 2y agoPOE very easily tends to inject noise into microphone inputs. If you run a Raspberry Pi for example with POE you get that. This can be fixed by using a power conditioning hat and a POE splitter but now the costs are really increasing. But it works.
- 15155 2y agoGalvanically isolate the ~100mA of supply current you need - the Ethernet interface is already isolated.
- hcfman 2y agoI’m pretty sure that Raspberry pi’s draw more than that. But if you have a good way to fix this I’d like to know. The pi supply hat also has that probably and no one has fixed it in a couple of years.
- banga 2y agoSee also https://app.birdweather.com/ https://app.birdweather.com/ which uses a community of stations using AI to match vocalizations with bird species. It was pretty easy to setup a Pi with a microphone using https://github.com/mcguirepr89/BirdNET-Pi https://github.com/mcguirepr89/BirdNET-Pi to start identifying birds outside my place.
- alhirzel 2y agoI collaborate on a project like this, but using a distributed network of a dozen or so dumb recorders within 50 miles of my house.
- is_true 2y agodo you use the same hardware? I'm interested in helping a local ornithologist setting one up.
- alhirzel 2y agoWe use dedicated trailcam-like recorders that drop `.wav` files to a 256GB SD card for a few months on four "C" size batteries. Several sites are very remote (islands separated from mainland by several miles), and recordings are scheduled for only 6 hours per day according to the study's focus.
- is_true 2y agoty
- sriacha 2y agoCan you elaborate on your setup?
- anitil 2y agoI'd be interested to hear more about this. I came close to working on a similar setup but the primary limitations were power and data connections. We figured we'd either need a manual rotation of batteries and storage, or maybe buried PoE to handle both. We never got past the initial concept
- alhirzel 2y agoOur slow-but-steady concept is down the batteries and storage fork in the road you lay out. Some areas are too remote for infrastructure, so we just revisit and change batteries and cards periodically.
- mcswell 2y agoAre there microphones that would let you "listen" to bats? We have bats fly around our house at dusk, it would be interesting to know what they "say", especially when two of them come close (unclear whether that's intentional or not).
- bearbin 2y agoThere are! https://www.omenie.com/pipistrelle.html https://www.omenie.com/pipistrelle.html
- hcfman 2y agoVery nice project the above. If you want to pay more you can also get Pettersen ultrasonic microphones. These have a USB microphone and will also work with my sbts-aru recorder. Which means you could in principle also geolocate where the bats are.
- anfractuosity 2y agoI've used Primo EM258 mics with an XLR adapter, they can pick up ultrasound, although the datasheet doesn't really mention this. See - https://zachpoff.com/resources/cheap-microphones-for-ultrasound/ https://zachpoff.com/resources/cheap-microphones-for-ultraso... Reading wikipedia "Bats emit calls from about 12 kHz to 160 kHz, but the upper frequencies in this range are rapidly absorbed in air.", so I guess the Primo wouldn't be suitable for the higher bat freqs.
- pfdietz 2y agoThe AI program for recognizing bird vocalizations, Merlin, is available on your phone. It's really changed how birding is done. It will detect and identify the species of birds in real time as you are walking around, often before you yourself recognize them (if you are even able to).
- quokka 2y agoMerlin is fantastic! But it it's not 100% accurate and currently focuses on birds from Canada, the US, and Europe.
- pfdietz 2y agoI've found it to be quite accurate here in upstate NY, with a few recognizable exceptions. In particular, sometimes it seems to think it's hearing a blue-headed vireo when a red-eyed vireo is singing. Also, it sometimes misreports yellow-rumped warblers.