Alarm Sensors (Beam type)

[dw3101]

Anybody got any suggestions for something like:

http://www.securitywarehouse.co.uk/..._page=product_info&cPath=36_37&products_id=85

I'm after something to protect a farm gate, or should I say sound an alert when someone breaks the beam, and probably turn flood lights on (can sort that bit with a photocell and a contactor easily.)

David

 

[breezer]

I would suggest you do not use them.

although they are a double beam they are flawed for external use.

What you should do, is to have 2 pairs of single beams.
Mount a tranmitter and receiver at each end about 30 cm above each other. abd obviously at opposite ends, wire the recivers in PARALELL

Tx1........................... Rx1



Rx2.......................... Tx2

That way a bird can fly through one, then the other, by which time the first one is clear.

it insures you do not get false alarms

you should not have both tx's at the same end as that means that 1 tx can hold off both rxs

a person not knowing they are there will walk through both, causing an alarm condition

as for where have you tried here

 

[dw3101]

Cheers breezer, thanks for the google link.. I never thought of that!

It helps if you know what they are called to do a decent search!

 

[breezer]

sorry i missed that bit.

active infra red beam

also try "radio visor" (popular maker of said beams)

 

[dw3101]

Cheers,

I shall now waste the rest of this miserable day whilst stuck at work with nothing better to do!

David