Ultrasonic Noise Generator

[aztek]

Hi,

I just built an ultrasonic device from a kit that I ordered online. The unit uses 4 piezo tweeters with a range of 5khz to 25khz and the power supply is a 12V/1.5A wall adapter.

My problem is that sound is not loud enough when I stand about 25 feet from the unit.

What modifications can I make to this design so that the sound output is increased.

Thanks

 

[ericgibbs]

hi,

What is the frequency of the ultrasound.?

 

[Sceadwian]

How are you measuring the volume in the first place? Piezo's have anything but a flat frequency response. Can you post any specs/model number of the piezo speaker you're using?

 

[HarveyH42]

Your not suppose to hear ultrasonic... Most people don't register much past 17kHz. 18 watt power supply, 50 watt speakers (?), probably about right. Is this to pester poor little animals?

 

[Sceadwian]

If he's generating 5khz though that's right near the peak of human sensitivity. Once again not enough details from the poster to answer their question.

 

[smanches]

If he's generating 5khz though that's right near the peak of human sensitivity. Once again not enough details from the poster to answer their question.

I can hear over 20khz. I've been tested many times. Funny thing is I can't hear anything below about 120hz, where most people can hear down to 60hz or lower.

Human range (hitting the extremes for all people) is ~50hz to 20khz. Hence why almost all hi-fi audio is in that range. A little lower on the low side for the "feel" effect of low frequencies.

 

[aztek]

I listened by ear at 25 feet with the unit set to sweep from 10khz to 25khz and I could whistle louder than the unit.

The unit was designed to deter both animals and people.

 

[Sceadwian]

Acoustical deterrents almost never work, the only way they do is if you put so much power into them you actually damage the hearing of the target. Without more information on the exact specifications of the piezo speaker you're using it's difficult to say what to do next, and the pdf's you posted don't provide a model number or driving requirements of your transducer.

 

[aztek]

I did a search for the motran transducer online and did not find any information.

Does anyone know the full specifications for the motran piezo tweeter (130db) ?

Also, what other cheap tweeters could I use to make the unit sound louder. I have a spare regulated dc power supply (13.8V/4A).

 

[Sceadwian]

It's a good thing you didn't get the output you were expecting, 130DB would have defend you .