Originally Posted by marcbarker

Is this a weapon? What kind of weapon? Maybe it's our cultural differences, but in UK anyway weapons enthusiasts are usually tarred with the same brush as members of organised crime and drug dealers etc. I think it's the personal safety aspect of this idea which may go against it.

I wouldn't go so far as to call it a weapon, almost everything can be used as a weapon -- that doesn't make it a weapon, it only becomes a weapon if it is used as such, it can also be a weapon per se if it was designed and/or implemented to be a weapon.

As such, I'm one of those guys who don't consider an air-rifle a real weapon -- i.e. air-rifles designed for target shooting, obviously air-rifles can be made to be lethal and have been such in the past. The common air-rifle bought in stores are designed for i.a. target practice. Yes, I agree you can use the air-rifle as a weapon, but it is highly ineffective and its use as a weapon is far outside the normal application envelope of an air-rifle.

The laser rifle is:

1) A research electronics/software project.
2) A toy.

A BB-gun can cause blindness just like the laser rifle can, but your finger in someone's eye can do that too, we can argue semantics all day, call the laser rifle what you want. The laser rifle is extremely ineffective as a real weapon, it has its dangers, but as someone who owns a real firearm I would treat it with respect in the event that it is ever even built, if that is something you'd like to hear.

Now this wasn't really the discussion at all I was hoping for, I don't understand why you are all so hostile.

I was looking for ideas and suggestions and technical input on the feasibility of the project as a whole, or in regard to particular ideas.

Originally Posted by dknguyen

Calling something a toy does not make it a toy. Last time I checked, bullets don't scatter. Lasers do. THat means you don't actually have to hit anything, people or aircraft, to do harm. This thing cause eye damage to people nearby and light burn things (but burning things is not the problem).

Continuous operation is irrelevant. Any exposure will cause harm. That's why it's class 4.

Your list of facts is flaws because you're thinking about causing damage to the plane and not the pilots. You don't need to hit the plane. You don't need the laser to be at full power, stable or continuous. And you don't know the attenuation of the laser. Probably is not good enough, especially when you have nothing to back that up. Pilots have noticed far weaker lasers.

Do you really want this to lead into a discussion regarding the dangers for imaginary retinas on imaginary pilots in imaginary aircraft in the event that some imaginary maniac gets his hands on my hypothetical laser rifle? You vaingloriously manage to overlook the fact that I explicitly stated I would never light this thing even remotely in the direction of any aircraft.

The fact is I haven't said anything very specific about how I would use it or treat it. Toy, yes, in some ways, but you can use a real race car like a toy too -- for entertainment and recreation -- that doesn't mean you shouldn't respect it, if you don't respect a race car it probably kills you; the laser rifle probably causes you some form of eye damage.

If you really think this is a productive discussion I urge you to go into any forum you can find on real firearms, race cars, motorcycles, rock climbing and anything else you can think of and tell them that what they're doing is dangerous and that they should cease doing what they're doing.

What about RC-helicopters? Aren't they dangerous? The main rotor on a 90-size helicopter would have no trouble cutting someone's carotid artery wide open. Should we stop that too? What about stray RC-aircraft flying into real aircraft that are about to take off?

I don't want this to be a political nor moral discussion on what should be legal and what should or shouldn't be done for the sheer value of recreation and/or entertainment, why do you?

Do you have any input on what I initially asked for? If not, then I wouldn't mind if you stopped commenting and trying to lecture me on dangers I'm either:

1) Already aware of.
2) That simply don't exist.

Thanks.

Originally Posted by dknguyen

So you felt the need to go and search for the forum to try and dig something up on me? Helicopters are flown at fields, guns are shot in fields. Do you have a laser field where you can guarantee the laser won't be exposed to the sky or people watching? That rules out anything outdoors.

This is just for a 5mW laser. And you're talking about 500mW or 10W lasers.
http://www.pangolin.com/faa/images/d...h_examples.gif

What you've made very clear is that you intend to not to keep it in an enclosed chamber and use it outdoors over long ranges where it would be exposed to others.

No, I didn't "dig up" anything, I pilot RC-aircraft and RC-helicopters myself and used it as an example for that reason. It is merely a coincidence, either you believe me or not. I don't really mean any harm at all, but I'm a bit offended that you think I'm an idiot, perhaps you guys are strongly opposed to anything even remotely weapon-related, even if merely created for the purpose of not hurting any animal or human, but merely for the intellectual challenge?

While your statement makes some intuitive sense at first, i.e. all you're saying is true, it doesn't apply fully in this situation.

Yes, we all do fly our RC-stuff on a field dedicated to RC-activity (except for park gliders and such), but does that ensure no accidents happen? There are spectators, a stray RC-jet can easily kill someone if it hits said person at 200 MPH in the face. Unlikely? Of course! But how likely is it that anyone will be hurt by what I'm doing? You can also run someone over with your own car if you're not careful.
One of the issues regarding this project as a whole is of course safety, I'm curious why you imply that I don't care about safety at all. Do I really sound like that much of an idiot? I really didn't mean to, and I'm sorry if I did. But why wouldn't I try to do this as safely as possible? I'm not exactly sure where and how I'd use it, I'm quite certain I can use it safely indoors, and I would be impressed if I could consistently and swiftly set things on fire at a distance from e.g. across the hall and a room, that would be neat. Outdoors? I don't know, that depends on a lot of things, many of which I haven't looked into fully as of yet, either way it would be treated like a real gun in any case.

How can I do it safely outdoors? Well there are many ways this can be accomplished, an example would be to use the local shooting range, which is often empty where I live -- there is only one entrance; I would merely bring a friend who would stand outside the door for the shooting range and alert me verbally if someone else wanted to enter the shooting range without eye protection -- in which case I'd stop my laser activity. Now the shooting range-guys might be upset that I used the range for something like this, but I doubt it, they are friendly people, but like I said there are factors I don't know about yet, this is one of them.

I don't even know if it would be feasible with optics to make the device effective at the ranges possible outdoor, I don't know what usual attenuation is on such lasers nor what optics would be required to make it effective at a long distance.

Originally Posted by dknguyen

Then enclose it in a chamber and crank up the power even more.


It's harder than a gun because you gotta make sure no one is actually watching you. Unless you lived on your own acridge or island I think using it outdoors is unwise because you can't guarantee no one would be watching. And at a place like a range, how do you guarantee someone doesn't accidentally look? I mean, you'd think they'd be super curious. UNless they all have safety goggles, which they won't because those things are a few hundred each.

It is a closed range, it is not possible to "look in" from the outside, and to ensure no one walks in despite this, I would have my friend, it is unthinkable that someone could walk up to the range and not be noticed by someone else (my friend) who has the job of watching for exactly that.

How safe is safe enough for you?

Since you're pretty new to the forum posix, you need to understand that there are alot of requests that border on illegal activity (remote detonators) or just plain stupid (grid tie-in with no experience in high voltage).

So you should agree that asking for a powerful laser in a "rifle" housing is suspicious. Maybe you DO have just educational leanings but I'd be surprised if anyone here helped you with that.

Maybe we got off on the wrong foot... welcome to the forum now don't hurt anybody or yourself.

Originally Posted by gabeNC

Since you're pretty new to the forum posix, you need to understand that there are alot of requests that border on illegal activity (remote detonators) or just plain stupid (grid tie-in with no experience in high voltage).

So you should agree that asking for a powerful laser in a "rifle" housing is suspicious. Maybe you DO have just educational leanings but I'd be surprised if anyone here helped you with that.

Maybe we got off on the wrong foot... welcome to the forum now don't hurt anybody or yourself.

Thanks.
I never meant to offend anyone; but it is hard not to get upset and defensive with apparently an entire forum against yourself. :-)

But I see your point; and seeing that the price (as function of effect) seems to be growing exponentially above ~200 mW it is unlikely that I will even want to spend the (probably) astronomical sum on a class 4 laser anyway.

Let me tell you a little secret Posix. To get back on the right foot with dknguyen, ask her out to dinner.

Originally Posted by dknguyen

Why would a $600 for 500mW laser be acceptable, but a 20W lasers for $2000 is too be too expensive?

Because I'm just a university student -- I'm not rich. :-)
Like I mentioned it seems the price does not grow linearly in proportion to performance once you start getting close to the limits of the class 3B; I assume few single class 4 lasers are sold to private individuals and that if they at all are sold they are even more expensive.