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Laser Tag.

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jpalomba

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Well, I have been an electronic hobbyist for some time now. I am 22 and was elated to find this site because its something I have always dreamed people would do. Well I breadboarded and IR laser tag which has been nothing new and it was ridiculously simple. A few photodiodes connected to relays and with IR led. I quickly got bored with it and was frustrated by its lack of range due to the light dispersing, even after tinkering with lenses to focus the light. However, I did move one to lasers. I was happy with the results.

However, there have been mixed talks about the effects of lasers on eyes. In this particular case I was using laser diodes but I suppose it also would be relatively simple to use a helium neon laser tube which I hear is not as harmful. But what I have heard is quite mixed. Some say that if there happened to be a accidental exposure to the eyes, then you most likely would blink and those chances combined with the unlikelihood of being hit in the eye, make it reasonable. However, others talk about lasers being quite harmful.

I have found online that there are laser safety glasses. **broken link removed**
They are reasonably priced as well. only 29$.
However, I am concerned because there is little information on eye protection regardign lasers and it woudl seem that there is little information on a this sort of "lazer tag" set up, done through laser diodes.

My questions is.. are these glasses all I need to ensure that there will be no retinal damage during use of the lasers. I am interested becuse if this project is sucessful I would love to share it with all of you. However, I certainly wouldn't want to bother unless I was sure I wouldn't blind you all.
 
Blinking is good enough to prevent eye damage with low power visible lasers. IR lasers dont trigger the blink responce because you can see them This makes them more dangerous. For a laser tag setup you will probably want some sort of beam spreader anyway to make it a little easier to hit the targets. This would reduce the risk by a lot depending on how much you spread the beam.

About the Helium neon tube: how dangerous a laser depends on its power output rather than the way it's generated.

If you modulate the beam and crank up the photo diode gain a but you should be able to reduce the power of the laser to below a mW which shouldn't be dangerous for limited exposure (especialy with a beam spreader).

Brent
 
bmcculla said:
IR lasers dont trigger the blink responce because you can see them...

I think he meant "can't"...
Also, with HeNe tubes, a high voltage power supply is necessary for operation. You wouldn't want to risk getting something like that wet if you're holding it in your hand. In addition, they're usually made of glass, so they're fragile. One drop to the ground could end the game. I think a laser pointer would be a better choice for a laser source -- less power required, much lighter weight and less fragile. JB
 
Yeah, I've been hit in the eye many many with lasers and I don't have a problem. Here, I found this on a website a while ago. Gives you a basic understanding.

WARNING

Extra precautions must be taken because of a laser beam's intense concentrated energy. Among other factors, the hazards presented depend on the power density, the frequency of the beam, and the time of exposure. Guidelines have established the classification of lasers.

A brief description of the classification is as follows:

Class I: Low-power beam. Not known to produce any biological injuries
to the eye or skin.

Class II: Reserved for visible-light lasers only. They are limited to less than 1 milliwatt output. Eye damage will result if stared into for longer than 1 second.
The normal blink response of the human eye will provide protection. Eye damage will occur if the beam is viewed directly by optical instruments. Direct (specular) reflection, as from a mirror, should be considered to be the direct beam.
Diffuse reflection of the light may be viewed.

Class III: Instantaneous eye damage will occur if exposed to the direct beam.

Class IV: Both direct exposure or direct and diffuse reflections will produce eye damage. Exposure of the skin to the beam is hazardous. The beam is considered to be a fire hazard.

Now, about the class three... my eye's aren't messed up, and I've messed around and beamed myself right in the eye before many times. Same with the class two. But, others may not be as lucky as me. Sooo... don't try this at home. :lol:

Anyway, I know this isn't what you asked for, but I figured these links I found for you might help anyway.

https://circuitos.tripod.cl/schem/r55.gif
https://circuitos.tripod.cl/schem/r94.gif
https://www.aaroncake.net/circuits/laserxmt.htm
https://www.electro-tech-online.com/custompdfs/2004/06/20mrvr2.pdf

Hope they help! Though... you didn't ask for it. :lol: See ya.

Rain
 
Wow, this seems like such a cool idea. Its a shame the guy never followed up. but I guess I had a few questoins. I know that it can be done with IR LEDS but for anyone who has every tried laser tag with IR LEDS they know that it sucks and that many times the hits dont register and the range is horrible. so I think lasers are a cool step up. However, All the laser tag I've seen has been indoors. All that ambient light and crap will probably mess up with the phototransistors trying to get the laser beam right? Also, people recomended a 1 mw beam dispersed to 10 mm or so, but that might limit the range as well once again due to ambient light. What if we decided to kick this up a notch?

Take a 5mw beam, then disperse it, but use the glasses like that guy was talkign about earlier. Im sure that it should keep people from getting beamed in the eye, and that guy said that honestly a 5 mw beam isnt going to kill somebody becuase they will probably blink anyways.

Does that sounds safe? I'm sure the performance would be a hell of a lot better with 5 mw dispersed and collimated
 
If you modulate the laser you can really crank up the gain on the receiver. A little bit of optics to filter out all but the laser wavelength would help keep the sensor from saturating.

You have to be careful with IR because it does not cause you to blink. My feeling is its a lot better to work on the receiver sensitivity than crank up the laser power.

Along with modulating the beam you could encode data in it. This would let people know who shot them.

Brent
 
Well, first off, let me explain a few things because this is actually a very confusing and complex situation. Most laser tag is IR. There are limitation to this of course. IR disperses just like regular light. its chitzy. and the range is horrible. Well compared to lasers of course. However, I only see this sort of thing on high end 500 to 600 the cheapest.

In my experience in life, if it aint been done, its probably because theres a good reason for it.

First off, this is the part that confuses the bejesus out of me is why is there nothing on google about this at all. As far as lasers go. I dont think he was talkign abotu using IR light. he was talking about using regular visible light. Assume we get a laser pointer, wouldnt be hard. a simple 1 mw laser pointer. I think it would be pretty easy to do. but you still have the limitations of the laser itself. you shine the laser outside and it wont go all that far. I mean maybe 100 or 200 feet but thats about it. im not sure if you could calibrate a receptor to see laser light past ambient light once its dispersed, but I may be wrong due to my ignorance with lasers.

The obvious fix for this is crank up laser power, but you did say there is an alternative by modulating and cranking up the gain? Explain. I am not familiar with what that would. In fact, to be honest, I dont know what modulating or gain means :oops:
 
if you used a laser though wouldnt you need to hit the reciever perfectly if it is not dispursed in some way?
 
WEll true, you would need to disperse the beam, but after it reached the desired width you would collimate the beam. as you would also do with an IR, but lasers travel much more coherently than IR light does. correct me if im wrong anyone
 
Modulatiing in this case would just mean flashing the laser at a specific frequency. This lets your receiver ignore anything not flashing at the right frequency. Since you can ignore the other light sources you can turn the gain up more without saturating the amplifier. Gain is the same as amplification. Saturation refers to the fact that an amplifier can't output a signal that is bigger than its supply voltage so the signal just stays at the supply voltage - which essentialy make the output meaningless.

Duffman: when you're comparing the two light sources you are talking about laser light and IR light. But there are IR lasers. What you're comparing is LED light vs laser light.

Brent
 
Actually...

Before seeing this posting I actually made a new post above about what to use in a laser tag gun. I read a certain company's website about the guns they manufacture, apparently they use fiber optics with a laser diode. Shouldn't optical fiber reduce or eliminate the spread? In the case of the vests the targets were larger than on an IR system which compensates for little or no spread on the beam. Are laser diodes closer to IR LEDs or actual lasers? Anyhow see my post above, there's more. And judging by the way they hyped this system it's the "best ever".
 
wel laser light is laser light. It doesnt matter if its from an LED or a hene tube or whatever. I am 200% sure there are expensive laser systems like steridian that use lasers. However, I'm not entirely sure its feasible for the scale that you and I are talking. The actual top of the line laser tag is the MILES system that the military uses. They encode data as to who hit you, and have a series of bands that can calculate where you got hit, how much damage, whether it would have been fatal, and they can calculate your accuracy.
 
That's true

True, the miles system is best, can't argue that. I guess I'm just talking in a commercial scope and more hoping for opinion on the matter. Does anyone else think fiber optics would be a better way to go? Sure sounds that way. The claims this company makes is that by using a Laser Diode along with optical fiber, it takes less maintanence. Apparently IR systems require realignment to avoid too much spread and being too far off from the visible "sight laser" used.
 
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