# How much mW laser is need kill roaches?



## 4sevens (Jun 27, 2004)

My new house is crawling with them on the outside. 
I'm wanting to invest in a nice green laser. Question,
how many mW do I need to be able to zap these guys from 5 feet?

It doesn't have to be green - could be other wave lengths.
I'm looking mW suggestions as well as actual products.
linkys?

thanks
david


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## PhotonBoy (Jun 27, 2004)

Hot water kills them.


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## 4sevens (Jun 27, 2004)

yeah, so does windex and boric acid.
i'm looking for something more entertaining.

For example, maybe setup the laser with a two stage switch
so I can aim with low power and then, BAM knock them out
several meters away.

potential problems that I see - burning holes on my deck or
places that I don't want holes. or shooting through a window
from the inside could burn holes on the inside of my house.

solutions - only use high beam momentarily once roach is on target
and just don't shoot through glass. /ubbthreads/images/graemlins/smile.gif

david


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## Kiessling (Jun 27, 2004)

um ... I do not think such a laser would be available, and even if it were, it would be highly illegal ... but i may err ... /ubbthreads/images/graemlins/icon15.gif
bernhard


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## BIGIRON (Jun 27, 2004)

Wow. What fun. Hope someone comes up with something. In the interim, a .177 pump-up pellet pistol with only one or two pumps works well and is challenging.


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## nerdgineer (Jun 27, 2004)

Besides being illegal, I don't think you can get to the power levels required without BIG bucks. I once saw a 2 watt blue-green (argon, I think) laser test. The beam was very narrow, about 2 mm or so and made dust in the beam sparkle very brightly. When we stuck a pencil in the beam, it would start to smoke in about 2 seconds and the small laser spot would be scorched black in about 4 seconds. 

Something like that would probably get the roach's attention, but even it might not be fatal as 4 seconds is a long time to a cockroach. You also would not want to be looking at the reflected spot from a laser like that for very long or very often.


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## sharkeeper (Jun 27, 2004)

10W CO2 (Synrad) does wonders! /ubbthreads/images/graemlins/smile.gif

Plug and play laser.

DANGER: Eye protection is MANDATORY with any Class IV laser used in such a careless (but fun) manner! 10.6 u is totally invisible, you only see the effects like charring of the target, etc. A 2mW hene or 10mW 650nM diode aiming laser helps tremendously. You can use a 800+ nM 10mW pointing diode laser for stealthy targeting. (i.e. lighting off cases of firecrackers from far away, etc.)

These 2W FC 830 nM diodes you see on ebay will behead a roach rather quickly too!

Cheers!


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## Doug Owen (Jun 27, 2004)

If we're talking laser, range is not an issue (within reason), right? Think about it......

I wouldn't worry so much about holes in the deck, or even your house. Your hide, or the hide or property of a neighbor that can find a lawyer is another matter, of course.

And it would seem that there are no Federal (and at least none in California) to prevent ownership of such a high power laser (I've checked, you should too), but normal liability laws are still in session. The courts aren't at all likely to look kindly on your not keeping the beam entirely in your property at all times. Unless there's no lawyers where you live......

Doug Owen


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## Lasernerd (Jun 27, 2004)

1 watt visible or invisible should be good up to 10 feet
of course colliminated beam


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## sharkeeper (Jun 27, 2004)

High voltage with decent current works wonders too! 

Cheers!


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## PhotonWrangler (Jun 27, 2004)

1) A roach is probably not going to stand still long enough.

2) If you accidentally hit something reflective on the ground, say a discarded gum wrapper, you could take out the eyes of an innocent bystander.

Look at the chemical methods instead (boric acid, etc). While less "entertaining," they'r emuch easier to control and less likely to land you in jail!
/ubbthreads/images/graemlins/eek.gif


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## Lasernerd (Jun 27, 2004)

Here`s a little bug zapper ..

http://www.repairfaq.org/sam/laserpic/bbsrpics.htm#bbsrtoc


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## i7r7 (Jun 27, 2004)

I remember my physics lecturer once said they made a 10kW CO2 laser, chucked it on the back of a ute (US = pickup) with a portable power supply. Of course they did have a proper legal use for it... starting fires in the outback for controlled burns. Apparently it could start fires in semi-dry forest up to 2km (~1.2 miles) away.

Now that would be able to burn a roach!!!

Jeff


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## 4sevens (Jun 27, 2004)

Whoa! jackpot! I'm building one of those.


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## Frangible (Jun 28, 2004)

Illegal? No. But the reflections of a laser powerful enough would cause permanent eye damage.

It would need to be far in excess of 10W. I've been hit with 10W and it stung and caused a bruise/burn. But lethal it ain't, especially to something as hardened as a roach.


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## The_LED_Museum (Jun 28, 2004)

Somewhere on the web, I saw a page that dealt with a ruby laser blowing up a stinkbug. I'm guessing the peak laser power was many, many watts.
So we're talking about many, many *thousands* of milliwatts here.
Definitely a CDRH Class IV rig here. /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/eek.gif

I think a laser like this would pose a greater danger of unwanted reflections than it would pose to a cockroach.


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## mattheww50 (Jun 29, 2004)

Not so much the energy, as the energy density. I'd bet money that if you hit the roach on the head (say about .1 x .1 inch area) with a 10 joules, the roach would be history. You'd have cooked (probably partially vaporized) a good part of the Central nervous system.

Spread 10 joules out of 10 square inches, and things get a little warm (but not overly warm). Put it all into a .01 x .01 inc square, and you can probably burn a hole through a couple millimeters steel.


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## robstarr-lite (Jun 29, 2004)

when its the season in my area and they are in my patio [ fortunately i've only seen them at night ] i pull out my trusty handy-dandy hand-held propane torch, which has a pizo-self starting spark trigger switch...granted its range it limited and i have to bend over [ good thing as i'd burn the place down ]...hey its not a laser but it puts out a decent enough flame that the little buggers cannot outrun either from hearing me approach or once that flame starts to warm their little feet...

don't know if i've given you an idea here david ...but you've given me one...i just might mount a weapons light and a small sighting laser on my bug zapper....thxs....for another project to hide from the wife!!

rob


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## [email protected] (Jun 29, 2004)

Hmmm, this might work as well (low tech approach...) /ubbthreads/images/graemlins/thinking.gif /ubbthreads/images/graemlins/cool.gif /ubbthreads/images/graemlins/naughty.gif 





Terminator Pistol


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## Myx (Jun 29, 2004)

maybe if you ran leads from a commercial stungun (or even touched them with the end of a stun-baton?)..... say 500kV........ might do it? Totally harmless to a human, but Id like to see what it does to a roach..... hehe


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## markdi (Jun 29, 2004)

My vector spotlight will kill them.
I was at a friends house and he had roaches.
a roach was on the ceiling I was chasing it with the spot from my 100 watt corded 12 volt spotlight hooked up to a 15 volt 12 amp regulated supply.(this was before I had a battery powered one) the roach ran faster and faster then it fell into my friends girfriends hair.
too funny.

any way
the spotlight and a mason jar killed roaches


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## David_Campen (Jun 30, 2004)

[ QUOTE ]
i'm looking for something more entertaining.

[/ QUOTE ]
I used to use 100% isopropyl alcohol in a spray bottle with a butane lighter as the ignitor to roast the little devils.


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## 4sevens (Jun 30, 2004)

Oh I love this thread.

So do you spray first and then light or spray through a flame?

When I was in high school, I used to entertain myself with a can of hairspray and a lighter.

then they took the lighter away.

/ubbthreads/images/graemlins/smile.gif

david


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## David_Campen (Jun 30, 2004)

[ QUOTE ]
So do you spray first and then light or spray through a flame?

[/ QUOTE ]
Light the butane lighter, hold it in front of the spray bottle and spray the isopropanol through the butane lighter flame.


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## 4sevens (Jun 30, 2004)

oh yeah. I just found my weapon of choice against these roaches

linky 

I just hope I don't damage anything nearby.

david /ubbthreads/images/graemlins/smirk.gif


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## kongfuchicken (Jun 30, 2004)

This guy is insane!
Totally, utterly insane!
...I like him /ubbthreads/images/graemlins/grin.gif
Seriously, he's gonna get hurt.


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