I'm building a dog training device. I don't want to zap or shock the dog, but just produce an ultra-sonic sound that will discourage current behavior.
I tried an online schematic and it didn't get any reaction from the dog. I was using one of these. I think that's a fixed frequency, so it doesn't work.
I need it to be very small (1cm diameter 1cm tall), but loud enough to make the dog notice and deter her behavior. What kind of transducer is capable of this? It needs to put out about 85db I am looking for something between 25khz and 40khz.
UPDATE:
From the comments and some more research, it looks like what I need is an "Ultrasonic Air Transducer". Is that the right term? I'm looking for something around 1cm in diameter and 1cm tall. Is this the right terminology for such a device, or are there other names I can search on?
It needs to be operational at 5vdc. Do they make such things? Do they make them with a variable frequency, or are they pretty much tuned in on either 25khz or 40khz?
Thanks for your help!!
Best Answer
The device you linked is a buzzer not a transducer- you give it a voltage and it produces a 2300Hz beep. It has a circuit inside.
You want a transducer that has enough output at high frequency-- to get a loud enough sound will probably require a tuned cavity resonant at the operating frequency or a lot of drive power. Unfortunately, most of the dedicated inexpensive ultrasonic transducers are mechanically tuned for 40kHz and the SPL will be considerably lower at 30kHz (Kobitone typical datasheet spec below).
If you are enterprising and have access to a few tools (such as a lathe) you might consider modifying (enlarging) the cavity of a 40kHz type to resonate at the lower frequency. The design equations are easily found online.