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Ultrasonic Wall of Sound

Discussion in 'd.i.y.' started by Julf, Nov 6, 2017.

  1. Julf

    Julf Evil brother of Mark V Shaney

    Winter is coming, so rodents try to move indoors. As I was thinking of how to discourage them, I came across some piezo tweeter horns being dumped really cheaply (less than € 2.50 each). Add a surplus class D amp and a Raspberry Pi, and you have the Ultrasonic Wall of Sound.

    Finally a valid use for a 96 kHz sample rate.

    [​IMG]

    [​IMG]

    Hmmph... Seems the forum doesn't grok Google Photos. Here is a link:

    https://photos.app.goo.gl/2yUkFdTbc3j6H4DS2
     
  2. gintonic

    gintonic Pussy Lover

    It does - you just have to use the link to the original large images and the insert image button. The images are rather large though


    [​IMG]



    [​IMG]
     
  3. Julf

    Julf Evil brother of Mark V Shaney

    Thanks! That's what I thought I did...
     
  4. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

  5. Mynamemynaim

    Mynamemynaim pfm Member

    Ultrasonic wall of sound??
    Was that a track by Andy Warhol?
     
  6. martin clark

    martin clark pinko bodger

    What's the capacitance of one piezo unit, Julf?
    With that much 'C' as a load, if you couldn't just use a mosfet and small inductor or two off the supply, and just do away with the rasppi and amp: free-running ultrasonic power oscillator.
     
  7. Julf

    Julf Evil brother of Mark V Shaney

    One unit is something like 0.13 uF. Pretty sure the commercial rodent repellent devices use a simple circuit, but I like the fact that I can make the signal more complex (random, dissonant frequencies at random intervals).
     
  8. martin clark

    martin clark pinko bodger

    I hope you’re gong to DBT that across random panels of rats ;)
     
  9. Julf

    Julf Evil brother of Mark V Shaney

    In this case I approve of sighted evaluation - if I don't see any rodents I am happy.
     
  10. martin clark

    martin clark pinko bodger

    ..until you get bigger, harder rats coming round demanding you play them nosebleed techno...
     
  11. Julf

    Julf Evil brother of Mark V Shaney

    Uh oh - I already ensured the signal was dissonant and random to allay the concerns my wife had that I might end up as an (electronic) pied piper of Hamelin...
     
  12. Cesare

    Cesare pfm Member

    Obviously this will only work for young rodents, the older ones will not know what the kids are complaining about.
     
  13. diybry

    diybry pfm Member

    I just use rodent poison. It even works without plugging it in
     
  14. Julf

    Julf Evil brother of Mark V Shaney

    I hate decaying rodents under floors and in walls.
     
  15. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    If you had more you could make an ultrasonic Wall of Death.

    Pete
     
  16. Julf

    Julf Evil brother of Mark V Shaney

    Hmm... I wonder if they still have them at the cheap price...
     
  17. davidsrsb

    davidsrsb pfm Member

    These cheap piezos are widely sold in SE Asia to attract cave swiftlets. People "farm" them in shoplot roofs for the edible (and expensive) nests
     
  18. grahamdocman

    grahamdocman pfm Member

    Isn't this what the Americans accused the Cubans of doing at the American embassy in Havana, if so I'm sure the Cubans were only trying to get rid of any rats :)
     

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