Powering an Ultrasonic Transducer

[Lindsay] has a wonderful writeup about a new toy in the shop, an ultrasonic transducer. The 28kHz, 70W bolt-clamped Langevin transducer by itself is not much use, you need a power supply, a horn to focus the energy, and a way to tune it. [Lindsay] starts off by showing how to find out the resonant frequency of the transducer, designing and building a high voltage high frequency AC power supply, and how to design a horn.

Not missing the meaning of DIY [Lindsay] casts and machines a horn for the transducer with a high level of precision as this will also tune the horn to the correct frequency. Once some brackets are machined the whole setup is put through some fun experiments in water and lemonaide, but the real purpose is to drill fine holes in glass for his home made Panaplex displays.

Join us after the break for a short video.

22 thoughts on “Powering an Ultrasonic Transducer

    1. It looks like a square wave.

      The two MOSFETs in the inverter alternately connect (one side of) the transducer to the high voltage, then to ground, giving a square wave.

  1. I’ve noticed that there hasn’t been too much done on ultrasound by the diy/maker community. It’s a shame since the idea of diy sonogram or Focused ultrasound (HIFU) would be pretty awesome… if somewhat dangerous!

    1. immerse the tranducer in a fluid, and the resonant frequency changes. The resonant frequency is proportional to the fluid’s density. (will only work for newtonian fluids). Figure out how to make that work for non-newtonian fluids and you’re an instant zillionaire.

  2. Ok… this is cool. Gives me a kick in the butt to work on something I’ve NEEDED badly. There is a dog, across the street from me that is left chained up in the garage for hours at a time. The garage door is half open, and the dog can come out and down the driveway a bit. He barks sometime for an hour straight at 6am, 7am, 8am… at night… doesn’t matter. And our master bedroom is on the side of the house closest to this damn dog. I was thinking about a bark detector, and focused ultrasonic dog blaster pointed right at the damn garage. The dog will learn real quick. The distance from my house to the garage is about 100 feet… this is the only limitation I think. Although, I COULD disguise it as a solar powered bird house and put it in one of my parkway trees… a mere 50 feet from the dog then. I think the dog owners and everyone else would actually appreciate this… they’ve hired a Bark Control therapist for their dog about a year ago… well, that didn’t work.

      1. the first step is to find out the power threshold you can use without making the poor dog deaf.

        next you need to fine tune an audio threshold for the bark. don’t want it going off when the neighborhood thugs drive through with their tunes blazin.

        after that comes the dev and testing phase. good luck with that. maybe after a few months you will get a nice product off the ground that you could market and have some nice supplement income for when the baby arrives.

      2. Or a little bit of social engineering. “Hello, Non-Emergency Police Line? My neighbor’s dog is barking at 4am and I’m concerned there might be an intruder.”

        Just a thought. :p

      3. @Sariel – I would likely purchase a cheap tabletop unit from the store, reverse engineer it. Then create my own and amplify it. Point it toward the dog, and when he’s barking… turn it up gradually until he stops barking. At first it would be wireless, and I would press a button to activate the STFUD2000™ immediately after a bark is heard… thus training the dog. After I know it works, I’ll work on making it automatic by listening for a pattern. The dog barks the same way all of the time… and the STFUD2000™ can have a “learning” mode where it samples for the “pattern”. It would also be timer based, so it would only be active during windows you set, to conserve power ;-)

        @andar_b – Non-emergency police number is programmed into my phone already ;-) I really don’t want to have to call them though because the neighbors are nice, and I don’t want any issues with them. Their dog just sucks.

  3. Lindsey’s article is mindblowing.(Thank you for introducing this article Kevin :)) Does anyone know how to figure out the diameter and wavelength distance(for node-antinode calculation) for an ultrasonic horn like he did?

    I plan to drill a hole through the bolt of a 40kHz langevin transducer and insert a pipe to form an ultrasonic nozzle, but I probably need to know or at least approximate the required diameter and length of that pipe in advance. Any help would be much appreciated :)

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