Re: Ultrasonic Sensors

["Stanley Barthfarkle" <sbarth@xxxxxxxxx>]

> 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 mounted 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?


Constant false alarms



> Therefore, I am looking for low-power, reliable sensors and the
> suggested controller to manage the system.
>
> Of course, price will be a determinig factor.


What you are proposing requires "dual photo-eyes". A type of infrared
invisible beam detector. Around $300 for a good set, 1 set for each
perimeter side. This is not a DIY project.