how do you make laser tripwire - Electronic Circuits Projects Diagrams Free

colin886 · 21st October 2005, 11:25 PM

Ive seen these in movies and think it would be cool to make.
if you know how please tell me how to make laser tripwire

Styx · 21st October 2005, 11:53 PM

ypu get a lazer and a photo-detector you mount them ontop of eachother (pointing the same way) then you have something reflective in the path of the lazer (pref a bike reflector to scatter the beam a bit) and the photodetector should pick up majority of the refected beam

if some1 breaks the beam phtodetector recieves no light and you can use that signal to trip something

zachtheterrible · 21st October 2005, 11:57 PM

http://www.electro-tech-online.com/v...ic.php?t=12983

I made this circuit. It will set off the little buzzer for a couple seconds whenver the beam is broken.

Dean Huster · 23rd October 2005, 01:29 AM

I think that the most sophisticated and reliable (in ability to detect) is a simple video camera with the "empty room" frame stored in memory. If that frame changes, there's obviously an intrustion. It's best for a windowless room, such as a vault so that outside lights such as autos don't trigger the thing.

Dean

roboticmisinfo · 23rd October 2005, 11:41 AM

Styx,

Shouldn't you have the laser and photodetector opposite eachother? That way, you wouldn't need to "scatter" the lazer - you could have it properly lined up... If the lazer was scattered, would that not increase the likelihood of an error? Sorry if I'm wrong but please explain cos I'm still learning.

Cheers, Mike.

zachtheterrible · 23rd October 2005, 05:03 PM

yes, you're right roboticmisinfo. thats the way I did it.

I'm not really sure what you're talking about styx, can you explain a bit more?

**Nigel Goodwin** · 23rd October 2005, 06:02 PM

Quote:

Originally Posted by zachtheterrible

yes, you're right roboticmisinfo. thats the way I did it.

It's often far easier to have the transmitter and receiver together (it saves running extra wires), place a small mirror opposite, and bounce the beam back to the receiver - the beam will be broken just as easily by an intruder, but it's easier to do.

I don't understand what Styx is on about either?.

zachtheterrible · 23rd October 2005, 09:05 PM

I think he means use a bicycle reflector as the mirror.

chemelec · 23rd October 2005, 11:46 PM

There is a Lazer Alarm circuit on my wesite.

http://www3.telus.net/chemelec/Proje...aser-Alarm.htm

Take a look.............Gary

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21st October 2005, 11:25 PM	(permalink)
colin886	how do you make laser tripwire Ive seen these in movies and think it would be cool to make. if you know how please tell me how to make laser tripwire

21st October 2005, 11:53 PM	(permalink)
Styx	ypu get a lazer and a photo-detector you mount them ontop of eachother (pointing the same way) then you have something reflective in the path of the lazer (pref a bike reflector to scatter the beam a bit) and the photodetector should pick up majority of the refected beam if some1 breaks the beam phtodetector recieves no light and you can use that signal to trip something __________________ Nothing is impossible. Once a problem is realised, the rest is just details

21st October 2005, 11:57 PM	(permalink)
zachtheterrible	http://www.electro-tech-online.com/v...ic.php?t=12983 I made this circuit. It will set off the little buzzer for a couple seconds whenver the beam is broken. __________________ I'm no electronics god, i just talk too much.

23rd October 2005, 01:29 AM	(permalink)
Dean Huster	I think that the most sophisticated and reliable (in ability to detect) is a simple video camera with the "empty room" frame stored in memory. If that frame changes, there's obviously an intrustion. It's best for a windowless room, such as a vault so that outside lights such as autos don't trigger the thing. Dean __________________ Dean Huster, Electronics Curmudgeon Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines). R.I.P.

23rd October 2005, 11:41 AM	(permalink)
roboticmisinfo	Styx, Shouldn't you have the laser and photodetector opposite eachother? That way, you wouldn't need to "scatter" the lazer - you could have it properly lined up... If the lazer was scattered, would that not increase the likelihood of an error? Sorry if I'm wrong but please explain cos I'm still learning. Cheers, Mike.

23rd October 2005, 05:03 PM	(permalink)
zachtheterrible	yes, you're right roboticmisinfo. thats the way I did it. I'm not really sure what you're talking about styx, can you explain a bit more? __________________ I'm no electronics god, i just talk too much.

23rd October 2005, 09:05 PM	(permalink)
zachtheterrible	I think he means use a bicycle reflector as the mirror. __________________ I'm no electronics god, i just talk too much.

23rd October 2005, 11:46 PM	(permalink)
chemelec	There is a Lazer Alarm circuit on my wesite. http://www3.telus.net/chemelec/Proje...aser-Alarm.htm Take a look.............Gary __________________ I No Longer accept Private Messages on here. All Emails to me Must Contain the Word \"Electronic\" in the \"Subject Line\" or they go Directly to my Junk Mail Folder. Email me at: chemelec@hotmail.com Website: http://www3.telus.net/chemelec