Hello from Massachusets!!!

[Oray111]

Hello everyone, i found this forum and seems like lots of knowledgeable people here.

I would like to build a laser beam “fence” in the back yard that would have the laser beams visible at night, but also when someone crosses the laser beam, it would set off an alarm or a lightbulb.

Kind of like the cheap driveway motion detection alarms but it would have a visible laser beam from the laser diode to the sensor that would receive the laser beam on the other end of the line.

The distance for each side of the “fence” line wound be about 40 feet. I would like to make it a V pattern, 2 laser beams each coming from each corner of the house wall to a receiver/sensor at the far end of the back yard/patio. It would be two beams one at waist height and another at knee level.

The purpose is mostly for entertainment/artistic purposes for my guests when they come visit, but at the same time act as a motion detection system.

From my research on here, I understand that I would need a 520-532nm spectrum laser to be best seen by human eye and needs to be at night. Are there any units or diodes that can be hardwired to AC power and be turned on continuously instead of the battery operated clicker ones which would have a heat sink or anything else to help it not overheat? Or maybe I can stagger two in the same direction and have them turn on and off taking turns every 10 minutes or so?

Also are there any receivers or sensors (not sure what to call them) like what I describe above that would receive the laser beam and then trigger an alarm or electrical impulse when the laser beam is interrupted?

Would appreciate your suggestions! Thank you!

 

[GSS]

Wouldn't LED lights work? like they use in elevators..

 

[paul1598419]

Wouldn't LED lights work? like they use in elevators..

I looked at this OP before and found it to be too silly to respond to.

 

[lasersbee]

I looked at this OP before and found it to be too silly to respond to.

Nothing Silly about it.... Been there done that. Good learning
Laser Project.
There are many circuits to do that out there. Google is your
friend.... The problems lie in how you set it up.

Also keep in mind Snow/Rain/Fog/Air Pollution will effect total
detectable range to begin with. Another consideration is moving
Vehicle induced Vibrations.

Good luck with your project and keep the Laser Power at a
safe optical power Level.


Jerry

 

[CurtisOliver]

Laser trip wires are simple and safe. Lasers being collimated light source will yield better response than an LED over a distance. And you can keep the laser power levels low and invisible by using a 1mW NIR diode.

 

[paul1598419]

Laser trip wires are simple and safe. Lasers being collimated light source will yield better response than an LED over a distance. And you can keep the laser power levels low and invisible by using a 1mW NIR diode.

Eye safe visible ones aren't. That was my point.

 

[Oray111]

Wouldn't LED lights work? like they use in elevators..

I’m looking for the beam to be visible as a straight line beam to go from each laser to the end point about 40 feet.

I looked at this OP before and found it to be too silly to respond to.

Why is my post to silly to respond to?

Laser trip wires are simple and safe. Lasers being collimated light source will yield better response than an LED over a distance. And you can keep the laser power levels low and invisible by using a 1mW NIR diode.

I’m looking for the beam to be Visible in the dark, not Invisible like the driveway motion detectors.


Thanks for the reply guys not sure if my post is clear enough but hopefully can get some more replies

 

[paul1598419]

There are no eye safe visible lasers that can be made into a fence.

 

[CurtisOliver]

I’m looking for the beam to be visible as a straight line beam to go from each laser to the end point about 40 feet.


Why is my post to silly to respond to?


I’m looking for the beam to be Visible in the dark, not Invisible like the driveway motion detectors.


Thanks for the reply guys not sure if my post is clear enough but hopefully can get some more replies

Then it’s not happening. Your laser would have to exceed eye safety levels for that to happen.

 

[Oray111]

ok thank you for your help

so I would need lasers above 5mw. It would really be a novelty show piece than a working functional safety fence/alarm type thing. It would be at knee and waist level so minimize eye exposure, and I can have guests wear the goggles especially if there are children.

I understand and researched the safety aspects of this, but instead of criticizing and poking fun, can anybody on this forum answer some of my questions from the OP?

Much appreciated

 

[RedCowboy]

Hello everyone, i found this forum and seems like lots of knowledgeable people here.

I would like to build a laser beam “fence” in the back yard that would have the laser beams visible at night, but also when someone crosses the laser beam, it would set off an alarm or a lightbulb.

Kind of like the cheap driveway motion detection alarms but it would have a visible laser beam from the laser diode to the sensor that would receive the laser beam on the other end of the line.

The distance for each side of the “fence” line wound be about 40 feet. I would like to make it a V pattern, 2 laser beams each coming from each corner of the house wall to a receiver/sensor at the far end of the back yard/patio. It would be two beams one at waist height and another at knee level.

The purpose is mostly for entertainment/artistic purposes for my guests when they come visit, but at the same time act as a motion detection system.

From my research on here, I understand that I would need a 520-532nm spectrum laser to be best seen by human eye and needs to be at night. Are there any units or diodes that can be hardwired to AC power and be turned on continuously instead of the battery operated clicker ones which would have a heat sink or anything else to help it not overheat? Or maybe I can stagger two in the same direction and have them turn on and off taking turns every 10 minutes or so?

Also are there any receivers or sensors (not sure what to call them) like what I describe above that would receive the laser beam and then trigger an alarm or electrical impulse when the laser beam is interrupted?

Would appreciate your suggestions! Thank you!

The problem is that any laser that you can see the beam of from any distance is going to be over 5mw and there could be other legal/safety issues with an unattended laser beam as well, so you're not going to want to do that.

As for a yard security beam here's one.

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www.ebay.com

 

[Oray111]

The problem is that any laser that you can see the beam of from any distance is going to be over 5mw and there could be other legal/safety issues with an unattended laser beam as well, so you're not going to want to do that.

As for a yard security beam here's one.

[URL unfurl="tru]

thanks but I’m not looking for a yard security beam like you linked. Also this system would not be unattended like you say. As I described in OP, it’s for novelty/show piece. I understand the risks.
I also tested a cheap 5mw green ebbay laser and it shows a pretty good beam at night outside so not sure why you said it should be over 5mw.

Just trying to get some advice on how to build this, not sure why some of you who responded seem to be so uptight here.

 

[Unown (WILD)]

Because we care about safety before we advise people with potentially unsafe usage. If you cannot handle that then you can look elsewhere

 

[Oray111]

I did mention multiple times I’m aware of the safety risks, so keep responding about the safety risks without offering advice on the build is not very helpful.

There’s nothing to handle lol.
Its about the value that this forum brings. Not very helpful for new visitors or users when the responses from members are just pretty much just shutting down an idea or calling my OP is “silly”. Instead of explaining how to make it work safely.

 

[Unown (WILD)]

Stop blaming the forum when it's you who do not understand. It cannot be done safely. Pay attention to what everyone is telling you. Good grief ...

 

[CurtisOliver]

Instead of explaining how to make it work safely.

It can’t. It will have to exceed 5mW therefore it cannot be done without additional safety considerations.