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AR15.COM
7/24/2011 9:58:06 AM EDT
If i was looking for a laser tripwire, any suggestions where i would look?
7/24/2011 10:25:11 AM EDT
[#1]
Garage doors have them now.

garage door safety beam  kit
7/24/2011 11:11:45 AM EDT
[#2]
radio shack has sold door entry chimes for decades. not a laser but still reflected light. inexpensive and might work.

ther are also "driveway alarms" that have a motion sensor, much like a motion detector light that set off a remote unit. it's thermal, not laser, but afofrdable and simple. usually have those in Lowe's or Home Depot IIRC.
7/24/2011 1:33:35 PM EDT
[#3]
Thanks guys.  I think i found what i was looking for.

http://astore.amazon.com/2012supplies-20/images/B002B96XWW

7/24/2011 7:28:04 PM EDT
[#4]
I like to hear ideas how to increase the range of those door safetys.


7/25/2011 3:40:41 AM EDT
[#5]
I have one of thoes cheap reflected light door chimes and it sucks.
It does not work in the dark and is very prone to false alarm when the ambient ligh level changes, like when a cloud passes in front of the sun.
7/25/2011 4:51:50 AM EDT
[#6]
Quoted:
Garage doors have them now.

garage door safety beam  kit


thats what I was gonna say too, cheap and easy.

J-
7/25/2011 8:47:17 AM EDT
[#7]

For the tinkerers out there, you can get IR laser diodes (emitters) and photodiodes (detectors) from the laser scanner assembly in a laser printer. Some of the diodes are sensitive to visible light, too, and work fine with a 635nm (red) laser diodes. Some don't.

Be careful working with IR laser diodes. You won't be able to see the output and can easily irritate or burn your eyes if you aren't careful.

This stuff can also be bought on eBay and various surplus and junk sites, too.