Have been asked to pertake in Laser trip wire project

[irishluck]

So Ive been asked by a "group"
(I wont mention the group just out of respect) to help per-take in a project.
Basically this group is getting grant money to study new ways in protecting small patches of land.

This project seems very simple to do and easy to accomplish.
Just had a few questions I guess to where I should start.

My main questions would be waterproofing the laser which I don't think will be to much of a challenge but also how to wire this up to a 120v wall outlet.

What type of laser would I use that is powerful enough to reach its destination but hopefully isn't going to blind someone. Should I use a red diode or a IR diode.

And how to set it to set off a sprinkler system when it is tripped?

I'm pretty sure I already know how to wire it to 120v wall outlet but the type of laser diode is what I'm after.

Any feedback will be helpful and or if anyone has done this, please share!

Thanks!

 

[chipdouglas]

you would need a laser and a some kind of photosensor to detect when the lasers beam has been breached. there are millions of threads about this very topic.

Michael.

 

[pschlosser]

There is grant money for THIS? :thinking:

Where do I sign up?

 

[NKO29]

Well, you would probably want something infra red and low powered for continuous duty cycle... As for 120v to diode that will be easy, all you would need is an AC-DC adapter and a small current regulating system. And you'd need some sort of photosensor to detect breaks in the beam. Only thing i dont like about laser systems is the fact that animals and even flying leaves etc can trip them?
-Josh

 

[pschlosser]

Another downside is when the beam is visible, a human will just step over or under the beam to avoid tripping it.

What is the total distance the beam must travel? How many mirrors will it bounce off of before entering the detector? If its under 50 feet and no mirrors, any 1mW visible beam will do. Up to 200 feet and 3 mirrors, a 10mW is more than enough.

I would avoid IR lasers, because of the difficulty in aligning the system and the poor beam characteristics of IR lasers.

Sprinklers? If you're looking for a deterrent to animals defecating in the yard, this should do the trick. But it won't be easy with off-the-shelf parts.

• You need a source for the beam.
• possibly some bounce mirrors.
• a beam detection device (photocell) to trigger the system
• a 24-hour timer or daytime shutoff system
• a short timer, such as 15-45 seconds to activate the sprinklers
• a sprinkler system on a timer using electrically activated valves.
• appropriate power supplies, wiring and knowledge to tie it all together.

Come to think of it, what ARE you trying to protect the small patch of land from?

Bats? Owls? Dinosaurs? People?

 

[irishluck]

There is grant money for THIS? :thinking:

Where do I sign up?

Yes there is.
SO Ive got some room to run with.

This system I am designing will use 2 laser and each laser will use 3 mirrors.
Also this isn't for humans. Its for animals. So there not going to know what the light is=D. Basically deer and racoons.

I prefer it to not be visible but barely visible is fine.

Mainly I just need to know what size laser I would need and how to run a constant power source to it.

 

[Things]

You haven't really given enough information to judge what power laser you'd need. Over what distance will it be? Does it need to work through fog/snow/rain/hail/dust?

 

[irishluck]

You haven't really given enough information to judge what power laser you'd need. Over what distance will it be? Does it need to work through fog/snow/rain/hail/dust?

Sorry about that. Here is the run down.

This project is a 2 year research study that will be tested on an acre of 1100' perimeter. It will need to run at a constant. Meaning all night. I have read that I can use photocells to turn the system on and off for night. Will need to work through snow, and rain. Not sure if it will work through that though. For now the "defense" system will been slightly high power sprinklers to scare off deer and racoons.

There will be 3 contact points that will have mirrors the laser will need to make its rounds through to come back and hit the sensors. Sensors and lasers will be housed out of one box. Box will be an all weather proof mirrors and prolly will be the same with the mirrors as well.

I don't have to hook up the system to the sprinklers but do not to provide an output on the system that will allow it.

Will need to run off 120v wall outlet as well.

Did I leave anything out?

 

[The Lightning Stalker]

For raccoon detection, everything will have to be pretty close to the ground. That means the grass will
have to be cut along the entire perimeter. Then several sensors and a beam expander or several lasers
to filter out insects and other false positives. The perimeter of one acre is 834.842969666', so I don't
know where you're getting the 1100' figure.

I'm thinking some type of DPSS laser would do the trick. 532nm if you want the beam to be visible or
1064nm if you don't. You could even use several lasers or partial mirrors at different elevations to detect
the size of the fauna present. Then appropriate photodiodes for detection and band-pass filters to only
let through the wavelength of the laser. The power of the laser would not have to be anything
extraordinary. 30mW would probably do it or maybe even less. Oops, did I just design a laser tripwire
system?

 

[irishluck]

For raccoon detection, everything will have to be pretty close to the ground. That means the grass will
have to be cut along the entire perimeter. Then several sensors and a beam expander or several lasers
to filter out insects and other false positives. The perimeter of one acre is 834.842969666', so I don't
know where you're getting the 1100' figure.

I'm thinking some type of DPSS laser would do the trick. 532nm if you want the beam to be visible or
1064nm if you don't. You could even use several lasers or partial mirrors at different elevations to detect
the size of the fauna present. Then appropriate photodiodes for detection and band-pass filters to only
let through the wavelength of the laser. The power of the laser would not have to be anything
extraordinary. 30mW would probably do it or maybe even less. Oops, did I just design a laser tripwire
system?

Im not worried about the grass thing. There wont be grass under the lasers path. Just dirt.

We will be using 2-3 lasers for the height. One high, low and medium for different sized animals.

The size isnt really all important right now. I was told 1100' perimeter so we'll just go off that!:yh:

I was thinking about using these CDS Cell Light sensors as far as the light detector sensor goes.
Overview | Photocells | Adafruit Learning System

What exactly is a DPSS laser?
Im not looking for a high powered laser that will burn or blind. But one that will last a while and wont burn out quick.

 

[Trevor]

Any laser low enough to detect a raccoon will be defeated by things like accumulating snow or tall grass. Falling rain, snow, hail, or really any precipitation will cause trouble.

IMO you're barking up the wrong tree using lasers.

A grant was awarded for this? Of all the things that didn't happen, that didn't happen the most... :thinking:

If this unnamed "group" did get a grant, why didn't the writers write someone into the grant who actually knows what they're doing...? :can:

Sounds like a DIY lawn management project disguised as "science" to make random internet people more likely to help for free.

Trevor

 

[Cyparagon]

You need to take a step back and state the problem better. "protect small patches of land"... okay, what size range? Protect from what? Protect how? You've skipped the step where you list several possible solutions, and jumped right to "let's use lasers!" and you're gonna have a bad time.

The optics required here will be rendered useless in a few months because of dirt and other contaminants. It will not work in poor weather. It will not detect flying creatures. I will not always detect tall creatures. The perimeter would need to be carefully maintained by a groundskeeper to keep it free from grass, snow, and other debris. Any other debris flying about in the wind will cause false positives. There are just SO many reasons why this is a bad solution.

Cut your losses and start over.

 

[irishluck]

You need to take a step back and state the problem better. "protect small patches of land"... okay, what size range? Protect from what? Protect how? You've skipped the step where you list several possible solutions, and jumped right to "let's use lasers!" and you're gonna have a bad time.

The optics required here will be rendered useless in a few months because of dirt and other contaminants. It will not work in poor weather. It will not detect flying creatures. I will not always detect tall creatures. The perimeter would need to be carefully maintained by a groundskeeper to keep it free from grass, snow, and other debris. Any other debris flying about in the wind will cause false positives. There are just SO many reasons why this is a bad solution.

Cut your losses and start over.

I've pretty much already answered all of those questions but will answer again

Okay. A university contacted me about a project they want to work on. A defense system basically to protect crops. The research area is a 1100' perimeter to test on. This is basically to install a trip wire system for animals from stopping them from getting into crops. When laser is tripped. It will turn on high pressure sprinkler system to scare them off (hopefully) All I'm doing is building a laser trip wire system. They just want me to plan out a design to stop ground creatures. Raccoon will completely destroy crops.

If a leaf/rain trips the system every now and then, then so be it. Snow I'm not worried about because the system wont be on in the winter being that there are no crops growing here in Missouri for the winter. Its not 100% fool proof but its a good idea to try.

This wasn't my idea, this idea was brought to me by a couple of people working at MU and another university that want to try this.


The way I plan on housing the laser will be in an all weather proof metal enclosure that with had 2 holes big enough for the laser to peek through.

In 3 other locations there will be all metal weather proof enclosures that will house mirrors to bounce the beam around the perimeter back to the original maser box of origin where sensors will be mounted.

 

[The Lightning Stalker]

I was thinking about using these CDS Cell Light sensors as far as the light detector sensor goes.
Overview | Photocells | Adafruit Learning System

That would work. It won't give a nice high/low signal like a photodiode though without
additional components. You could even use photovoltaic. That might even work better.

What exactly is a DPSS laser?
Im not looking for a high powered laser that will burn or blind. But one that will last a while and wont burn out quick.

Here is a link to info about DPSS lasers.

 

[Cyparagon]

This wasn't my idea...

Have you made your superiors aware of the problems here?

 

[irishluck]

That would work. It won't give a nice high/low signal like a photodiode though without
additional components. You could even use photovoltaic. That might even work better.



Here is a link to info about DPSS lasers.

Ha I like that "Let me Google it for you" thing. :beer:

I've got some pages opened up on them to read about them.

Right now im just trying to figure out a basic budget. Its going to be a 2 year long project of research. Some of you may think 2 years to build this trip wire system? Its not just for the trip wire system. This is just one slice of the project that were working on.