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Ultrasonic Sensors

My need is to monitor the perimeter of an outdoor area. I am considering ultrasonic sensors to act as an intrusion monitor. They need to be mounted near ground level.

I need a device similar to what I see on upper-priced automobiles that indicate the presence of items around its perimeter. I have seen a very nice system on the bumper of a BMW that works extremely well to indicate a person walking around the vehicle.

The sensor must be designed for outdoor/external applications.

There will be a series of sensors with patterns that overlap to provide detection around the entire perimeter. They will all be wired to a controller that will sound an alarm when the perimeter has been entered.

Perimeter size can vary from one hundred to several hundred feet.

Since they will be used outdoors, what will the issues be?

Therefore, I am looking for low-power, reliable sensors and the suggested controller to manage the system.

Naturally, total price of the system will be a dominant factor.

Reply to
rgondzur
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Anything else before we all run around looking for you ?

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Regards ......... Rheilly Phoull
Reply to
Rheilly Phoull

He didn't actually say it but I suspect he'd like a schematic too.

Graham

Reply to
Pooh Bear

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Reply to
Fred Bloggs

Cats, dogs, bats, birds, tree frogs, moths, bees, bumble-bees, spiders, big old fat spiders, leaves, dust, pollen accumulation, rain, hail, snow ...

Regards, Joerg

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Reply to
Joerg

I did some ultrasonic motion detector work many years ago. Curtains moving when the A/C comes on would trip it :-(

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

Hello Jim,

I make most of my living off ultrasound. You really have to know the properties and behavior of the medium and the targets. I remember when I was asked to check out a Doppler that was repeatedly falling from grace in the clinics. I found that it didn't have any dynamic range to write home about. So I told the engineers about wall echoes and that those can be 40dB or more above the desired signal in a patient with bad plaque. "Aw, s..t!".

Then we designed a new Doppler. Sans Gilbert cell mixers...

Regards, Joerg

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Reply to
Joerg

A vehicle fan can take out most ultrasonic sensors for several hundred feet.

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Many thanks,

Don Lancaster                          voice phone: (928)428-4073
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com

Please visit my GURU\'s LAIR web site at http://www.tinaja.com
Reply to
Don Lancaster

Since you wish to monitor the perimeter, not the area within it, I would go with pairs of modulated IR emitter/detectors at the corners.

Luhan

Reply to
Luhan

Don't forget wind -- certain air currents, especially including thermal gradients, give nifty drifty ultrasound returns just like those from targets.

Lightning, or, actually, thunder, might be interesting too.

Cheers, James Arthur

Reply to
dagmargoodboat

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