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Thread: Bat detector

  1. #576
    Junior Member
    Join Date
    Oct 2019
    I'll follow-up via PM but in the meantime I put a summary on my website:
    Many thanks to Edwin and Cor for making this tool possible. As time goes on I'll update with audio samples.

  2. #577
    Senior Member CorBee's Avatar
    Join Date
    Jun 2018
    Hi Zach,

    Thanks for sharing! Lets hope this encourages more people to hear bats and other animals. On your great webpage I also see you have experience with hydrophones, one of my hopes is that we can also develop a "hydrophone" mode for this detector. That is one of the reasons for me to use mics that are in mounted in a microphone connector so I can (whenever I build a hydrophone) just connect a cable on that point.

    looking forward for the coop,


  3. #578
    Join Date
    Nov 2018
    Looks very nice Zach.

    If you want to try and get rid of the 23khz noise, it might be a good try to use an other microphone. In the pictures I see you use the ICS microphone which seems to have a similar issue as the SPU. The frequency does seem to be slightly different though.

    I also have a recording made with the same type of microphone using an alc4040 (from a maono elf pro AU-410H, I do not recommend dismantling one!)
    (I hope to try and see if I can also use ALC4042 and ALC4050 soon, these are available as micro USB boards)

    This first one is in a quiet room without switching powersupplys and lights off.

    Click image for larger version. 

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    This second one is with my faucet aerator (perlator) noise generator.
    My recorder (raspberry) was quite close as well and I did not bother about the led lights.

    Click image for larger version. 

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    You can see that signals around 23khz are always more present that other frequencies.
    The microphone is amplified by a similar circuit as what I use in the teesny.

    Anyway, I feel it is safe to say that the 23khz is not coming from the teensy or how it is built. We should search for it in the microphone or maybe in the amplifier circuit. It would be nice if someone had an other type of microphone like Knowles FG and record some files with the teensy.
    (I protected my microphone, amplifier and codec in epoxy resin, so I can not test without the amplifier)

    Kind regards,


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