producing ultrasound

Did you want the sound to be inaudible?

......... Phil

could

Don't you know what ultrasonic means?

wrote

could

Yes. So will clapping your hands.

"Anthony Fremont"

....... Phil

"Phil Allison" wrote

Speaking of autistic behavior, why don't you just answer the question asked instead of the giving an answer to an unasked question?

why dont you both stop the childish arguments, as they are largely uneducational and unresolving and just add to the mass of online bullshit.

wrote

And exactly what are you doing now? I gave you the answer to your question and now you take a slap at me? You might also wish to learn how to make a post that contains some context.

--Hmm. I guess you could look around for an old ultrasonic cleaner. I'm remembering rule #1 with these units: don't run them empty. I'm thinking whatever you wind up with, you should make sure it's only in use when there's a load on it, else it blow up or something..

Sure - a little tuning fork with a resonant freq. of 40 KHz. The earliest TV remotes did this - there was a little hammer that whacked the tuning fork. The TV, of course, had a regular receiving transducer.

Or, look at some music boxes and figure out how long of a prong it would take to vibrate at the target frequency.

Or, take something like a cricket wing, and stroke it very, very fast.

Good Luck! Rich

"Anthony Fremont"

....... Phil

Absolutely! In fact, ultrasonic "sniffers" are one way of detecting leaks in high-pressure steam systems. In the natural world, most cricket-type insect sounds are made by scraping two structures together, and these sounds have very high ultrasonic content.

I suspect if you build a detector you will find all kinds of ultrasound around the home, and definitely around any mechanical shop.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

An electronic ignition, based on piezo xtals, will produce a point source very sharp US pulse (very good for accurate distance measurements), but I guess, whil the source is mechanical, there is still a current ;-)

Stef

Galton and Hartmann whistles can produce very intense ultrasound from compressed air. These are easy to make if you have a lathe.

Sirens

Impact a metal bar, like a chime, that is resonant at an ultrasonic frequency. Ultrasonic chimes are usually solid bars. Some early TV remotes (Raytheon) worked this way. No batteries!

Google on ultrasonic whistle. You'll find other possibilities.

And if you don't have a lathe handy, you can go to a pet shop and buy an ultrasonic dog whistle for under $10. Hook up a can of compressed air(as used for dusting off electronic stuff) and you'll have an on-off switch. Most of these dog whistles can also be tuned slightly.

Cheers! Charlie

Sure, many animals (bats, rodents, insects) produce ultrasound for communication and echolot. Gas leaks can be located by the ultrasound they produce, much safer than with a lighted match. Wind noise contains ultrasound. And many high frequency speakers can also be used for the production of ultrasound, at least in the 20-30 kHz range.