Question on visibility & power

[thescene]

Hello everyone!
I'm looking for advice and hoping one of you could help me. I'm wanting to purchase a laser that has a power outlet adapter so it can be right next to my security camera during the night and it that has a visible beam. I don't want a really strong laser because I plan to have it on for multiple hours and I don't want it being capable to burn wood since the laser would be pointing at my wooden porch. Any suggestions on what laser would be a good fit for me or something I could put down on my porch so it wouldn't catch fire?
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I found two on Amazon and eBay. What do y'all think?

 

[Benjamax]

Hi and welcome,
30mW of green is decently visible at night, in a place with little to no light pollution, and specifically when looking along the axis of the beam against a dark background.
I don't think burning is an issue as long as you're able to screw it a little out of focus. I would worry more about eye safety.
What are you trying to achieve?

 

[thescene]

Hi and welcome,
30mW of green is decently visible at night, in a place with little to no light pollution, and specifically when looking along the axis of the beam against a dark background.
I don't think burning is an issue as long as you're able to screw it a little out of focus. I would worry more about eye safety.
What are you trying to achieve?

Thank you for your response! I'll make sure that it is out of focus by a little. My fear was if I have it on all night long it'll burn my wood porch or even set a fire. The whole purpose of this purchase is to be a deterrence for home invaders/robbers. My house had just got broken into last week and I bought some cameras. I thought having a laser right next to the camera on my porch would be a great deterrent and make someone think otherwise from coming on my porch.

 

[Encap]

You should check with your Insurance carrier as to whether or not you are covered in the event someone damages their eyes from any laser eye hazard you decide to put up----don't think it would matter if invited guest or robber or kids investigating the green light beam---you could be sued for creating a hazard that damages someone's eyes.
Any laser with an output >5mW is an eye safety/eye damage hazard.
Will it be installed in an area where no eye exposure of anyone is possible.
Read up on laser safety at this excellent site: https://www.laserpointersafety.com/
Laser Class 3B, 5mW to 499mW safety info here: https://www.lasersafetyfacts.com/3B/
Eye Hazard chart here: https://www.lasersafetyfacts.com/resources/FAA---visible-laser-hazard-calcs-for-LSF-v02.png

The two units you mention are meant to project a line --there will not be much of, if any, beam to see, the beam being spread out very wide to create a line on whatever target the laser is pointed at--as in line on a deck or wall.
A dot unit will have a much brighter beam. The diameter of the beam plays a role in its ability to be seen, and the thinner, tighter, more concentrated the beam is the easier it is too see
Seeing a beam will depend on the viewers distance away and position relative to the laser beam as well as atmospheric conditions. A laser beam is invisible regardless or power or wavelength in a vacuum. Seeing the beam depends on particles in the air reflecting the beam to the viewers eyes. Holding the laser in your hand and seeing the beam is different from visibility a distance away and/or perpendicular to the beam.

Will the laser unit be exposed to outdoor weather rain snow and so on---those two are meant for indoor use?

Might be a good idea to get one of the low cost 532nm laser 301s on eBay for $5 to $10 to see if that dot type output and beam brightness is what you want. The output on those vary usually between 50mW and 100mW or so --output is pot luck at those prices.

 

[Benjamax]

A green beam isn't going to deter anyone. I happen to install home and field security systems. Although they're mostly local and proprietary, I've had some experience with Amcrest products and was happy with their systems. A good DVR software allows you to select specific area sections in the field of view of each camera, tune the sensitivity for these customized spots, and configure them with motion detection. The DVR can then alert you with audible sound, as well as notifications to your phone via an installed app, as well as recording whatever happened. You can watch live feeds and recorded footage through your phone too and have full control over every aspect in the system. Xiaomi and other Chinese brands also make standalone cameras that function as their own DVR and work with an app on your phone through a cloud server in between.

Will the laser unit be exposed to outdoor weather rain snow and so on---those two are meant for indoor use?

An important point to consider about laser being outside is that DPSS green lasers will stop emitting green light in cold temperatures but continue emitting their IR. Unsuspecting person may think it's not working and look right into the aperture.

 

[Encap]

Good points above^^^ not to mention exposure to wet weather and dirt/dust if used outdoors and not designed for outdoor use.
A green beam would probably attract more attention than it prevents and most likely not deter any determined burglars/robbers.
A sign that says " 24 hour video surveillance" would be a better deterrent, I would think.

 

[thescene]

I do agree that it is important about the safety of yours and other's eyes when dealing with lasers, but I don't think I need to worry about damaging someone else eye. The reason why I say that is because it's only going to be on at night and nobody is invited over on my property so if you come onto my property you're uninvited and trespassing. I even have a no trespassing sign presented that's light up at night. As well, I don't have kids living at my house so I don't need to worry about that.
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Yes, it would be exposed to outdoor weather such as temperatures, but it most likely wouldn't get affected by rain or snow since it'll be on right under the roof of the porch. Also, where I live it doesn't get that cold.
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Thank you for providing detail on how the beams work. If you don't mind me asking, but do you think this laser would be a good one for what I'm looking for?

 

[Benjamax]

50mW green beam at 14mm diameter spot would be fairly invisible.
The deterrence effect of a simple laser beam against criminals is highly doubtful.

 

[thescene]

50mW green beam at 14mm diameter spot would be fairly invisible.
The deterrence effect of a simple laser beam against criminals is highly doubtful.

It could deter a criminal or it could not, but it's still something and I honestly think it would be pretty cool to set up for the camera. I just have one last question and that is would the 50mW burn or even have a chance of setting my wooden porch on fire?

 

[Benjamax]

50mW de-focused to 14mm is not going to burn wood from a distance, but is still very dangerous for eyes.
A lot of what's on the market is often mislabeled and higher than declared. Most of the non-red common and cheap lasers emit a considerable amount of IR too.

 

[Cyparagon]

WHY do you need a line laser illuminating your porch? What does this accomplish for you?