Does any have motion lights for home defense? If so read this.

[ccw007]

I was talking to someone about home security a few months ago and they told me something that I would like to bring attention to because I have not seen it discussed here.

They told me that the high output green lasers will damage the sensor to motion lights. The lights will fail in the open position and the light will go off permanently.

The laser must be a high output green laser and can be found for about 100.00. They are used with astronomy normally and are visible up to 4 miles away. They said it was never a problem before because these lasers were so expensive until recently. However, now they are cheap and unrestricted. BG's are using them on motion lights so they can get into homes without the lights going off and without any noticeable damage to the lights. Apparently they will disable the lights the day before the break in. Since there is no damage to the lights it is not noticed. If the home owner sees the light is not coming on they assume the light bulb has burned out.

My lights have an option to turn on at night, so I have enabled this. Now if my light is off I know the bulb is gone or someone has tampered with the sensor and will investigate it immediately.

I have looked for this to confirm if it was fact or fiction, and cannot find anything that proves this or disproves it. My hope is that someone on THR may know more about this.

 

[jamz]

Huh, didn't know this. Interestingly, right before I read this, I had just ordered a high output green laser! I may have to test this theory out with one of my motion sensor lights that I'm replacing.

 

[ccw007]

Please post the results if you do that.

 

[tellner]

How many burglars take that much time and professional pride in their work as opposed to the smash-and-grab sort?

 

[Zoogster]

If that is true a much more effective tool woul be a highpowered infrared laser that is totaly invisible. The green lasers of the same power as the old visible red ones are only brighter because the human eye's pigment is more sensitive to green so you see it as brighter. The law limits the power to under 5mw on a pointer unless you have certain license etc in the USA. You can still aquire them but it is difficult. That is why they all say <5mw. More powerful ones are different classes that they can't market as laser pointers in the USA to the general public.

The part of the spectrum is less important to electronic sensors than it is to the human eye, so green should be no more effective than red or even invisible infrared. Cameras see infrared light the same as regular light, and many use them to illuminate for security cameras. Especialy black and white ones, as color usualy by default have built in IR filters that must be removed.

So this is likely just some nonsense to have criminals shining very bright visible pointers around neighborhoods.

 

[bearmgc]

I hope its all nonsense. I just decided to put motion lights in my yard, and on the side of my house, as a couple days ago I noticed my dog intensely sniffing up the side of my house where my bedroom window is, and the gate to the side of my house was unhinged. Fortunately, the 6ft high wood gate was firmly frozen to the ground, and would take major effort to pull it loose to open it completely. But it was enough to concern me.

 

[SniperStraz]

Its not like in the movies guy...

...If this guy is breaking into your house to steal your TV I doubt he spent $100 or more on superdeduper special green laser. Unless you've done something to offend Ocean's 11 or 007 I wouldn't worry too much.

 

[Robert Hairless]

The easiest way to defeat a motion sensor light is to shoot each lamp with a BB gun. This low tech method also works on other lights.

 

[Brass Fetcher]

Could they use a BB gun instead? Matching the solution to the problem, etc. It's akin to developing a EMP weapon to neutralize the security cameras at the convenience store. Cost far exceeds benefit to the criminal.

 

[Robert Hairless]

JE223 and I must have posted simultaneously. He didn't copy me.

 

[Shweboner]

...If this guy is breaking into your house to steal your TV I doubt he spent $100 or more on superdeduper special green laser. Unless you've done something to offend Ocean's 11 or 007 I wouldn't worry too much.

Agreed.


most likely they will run past the light rather than stand there in the light trying to hit the sensor with a $100 laser. Or if they are determined to defeat the light ... they could just walk up to it and smash it.

 

[Robert Hairless]

Perhaps this summary of a Mythbusters might be interesting too: http://kwc.org/mythbusters/2006/12/episode_59_crimes_and_mythdeme.html Scroll down to the section on "Thermal Motion Sensor."

The more I think about it, though, it might be possible for a bad guy to wear a dog suit. Then, when the lights come on, all he has to do is lie down and "Woof" a few times until the unsuspecting homeowner decides he's only a stray dog. I suppose if he gets good at it he might get adopted as a stray, then rob the house while his owners are asleep.

Lots of terrible possibilities out there.

 

[ccw007]

Just to clear up a few things I did not point out. When he brought this up, he was not talking about random break-ins to still your TV. It was planned on upper-class homes where they knew they could get a huge pay off. The common crook did not do this either. The BB gun idea may work to take the light out, but it would leave obvious damage if they did not plan to break-in that night. I would think loosening the light bulb would be easier unless it was out of reach.

Anyhow, this is one of those that came from a friend who heard from his brother who is friends with a guy that knows a LEO that heard from a class on tactics used during home invasions. I called BS when he told me, but it got me to thinking and I could not find anything either way and after reading some of the laser warnings made me think it could be possible.

 

[Brass Fetcher]

It would be interesting to know the 'power' of said green laser, IE how many lumens per square inch can it put out versus the intensity of direct sunlight? The sensors are most certainly designed to withstand at least this intensity.

IIRC, sunlight is most intense in the green wavelength, that is why plants are green, to make use of this fact.

 

[HankB]

It would be interesting to know the 'power' of said green laser, IE how many lumens per square inch can it put out versus the intensity of direct sunlight? The sensors are most certainly designed to withstand at least this intensity.

Hmmm . . . let's see . . . lumens are a photometric quantity, weighted with the spectral response curve of the human eye. I'd guess that the sensors are more sensitive to total energy (i.e., watts, milliwatts, etc.) than to lumens. Doubly so if they're infrared, as invisible wavelengths produce zero lumens regardless of power. (Aren't most motion sensors either IR or microwave based?)

Total solar irradiance at normal incidence (going by memory here) is about 1400 watts per square meter, or 140 milliwatts per square centimeter. Given normal beam divergence, not many "consumer" lasers will produce this level of irradiance at the distances typical of IR motion sensors.

Higher powered lasers are available without too much fuss or bother, but prices go up rapidly.

 

[Spreadfire Arms]

i have no idea if this is fact or fiction. i do, however, see a new addition to the the arsenal of the feared "mall ninja"

 

[Brass Fetcher]

HankB- my fault, 'magnitude of incident energy per unit area ' is what I meant to say.

 

[BSlacker]

I work with medium power argon green lasers(16watts max). We use photo cells to determine the power of the laser by directing about 3% of the energy to the cell. That is about .5watt at max power. That is 500mw and the cells don't burn. If you place even a clear piece of plastic in the path it burns like right now gets dark and blocks the beam. It maybe possible to burn the cheap photo cell with a green laser but it ain't a 5mw one. Most home type motion detectors have a plastic cover over the cell. Once enough energy to burn the cell is present the plastic cover would burn blocking the green beam and you would need more power to burn through too the cell. If you had enough to blow a hole and hit the cell the laser and supply gets large. Two and a half watts green for .05 seconds will fry the photo cell of an expensive meter head, ask me how I know . Show me a 3 watt portable laser that will burn the plastic cover first an then hit the cell and fry it. Well it just ain't possible IMHO. It also will draw a lot of attention as it will be very bright as it hits the sensor. Getting a good collomation cheaply at driveway distance, so you have enough energy density to burn is about impossible.
Maybe I will take one to work and try it. But I think most crooks don't have access to lasers above 10mw. Sounds fishy to me.

 

[mrmeval]

They are reasonably easy to defeat with a simple sheet of plywood.

 

[DoubleTapDrew]

That sounds awfully sophisticated for your average smash and grab theif. If it was planned for an upper class home chances are they'll have security systems that make motion lights look like childs play.
Once they get inside they better hope their laser will stop buckshot.

 

[Geronimo45]

They could also use suppressed PSG-1s with starlight scopes. Or hop out of helicopters and smash through a skylight.

 

[Robo_Railer]

My first stop was the Urban Legends Reference Pages (snopes.com), but all they had was something about coating the edges of music CDs with green ink for better sound quality. (FALSE)
Then I ran across something from back in 2001, on the forum at observers.org, apparently an astronomers' forum. That discussion was about pointing a laser (red or green) at the photocell of a streetlight to shut it off while ogling the night sky with one's telescope. Best I can tell, it only works as long as the laser is "on and pointed at the right spot." Some of the guys apparently use a spare tripod to maintain contact between the laser beam and the photocell.
I didn't read through the entire thread, but that's my take on it. No anti-motion-detector death ray discovery, as far as I can tell.

 

[chipp]

anyone know how to put out mercury vapor lights?

 

[BSlacker]

Street lights work different than motion detectors and can be turned off by shining a strong visible light source into the photo cell.
Motion detection is done by sensing the actual wavelength. MDs use two pyros(these cells are sensitive to infrared more than visible)they are tuned and filtered to see 900nm wavelength. The circuit behind the pyros looks at the output of each and if there is a responce on one then the other it triggers a alarm. If both are about the same no responce. So it detects motion not still infrared hot items like a hot car in the drive. They have a visible(green) light filter. The plastic panel we have all seen that the pyros are behind. This is to block visible and pass infrared light so one must overcome this first before the pyros can be hit with your puny laser. I have burned a bunch of stuff with a green laser and with a 1mm beam, it takes about 350mw to burn a hole in a business card in under a second about .05 seconds will do it. You will have to have a large laser to overcome the first plastic filter, maybe 5w. Now you come to a lense that is used to focus infrared onto the pyros. Now that you have burned through the plastic cover and alerted every person within a 1/4 mile with the green backsplash. The neighbors around here have noticed a green glow from my place from time to time . Humans are very sensitive to green. Pyros are not. The pyro detector is about 1mm in length and about .5mm wide. You will have to hold your puny laser on the pyro long enough to get it to produce enough current to fry the tiny traces on the substrate. The pyro is not sensitive to green so it will take about 3w to kill it applied over a good second. Have you tried to hold a laser pointer still on a 1mm target for a second 90 ft away. Good luck if you can even see the pyro much less hit it at 90ft. A large beam that you could flood the pyro with would have to be around 50w to kill it after you burned a hole in the plastic with your super duper focused laser. It ain't possible IMHO. Plus you must do both at once or it will trigger from the infrared from the hole burn heat. To much stuff against this to work.
One can easily and cheaply defeat simple motion detection by dressing funny to contain the infrared signature. This will let you get close to the light to pass by.
Thats is why all Zombie detection at my place is done by video motion detection. Gets those pesky cool blue ones everytime. Your milage my vary.

 

[Sheldon J]

Did someone say Green?

Been wanting one but they are way too pricey for me, I'd rather put it toward a new AR. but for the curious http://www.wickedlasers.com/products_overview.php#green lots of neat toys here