Possible non-burning visible beam mock-up?

[szopaw]

To give a little idea for what I'm aiming for: I want to make a prop laser gun. It doesn't have to actually do anything, but I've decided it'd be awesome if it did. I could use a 2-5W blue laser diode like some people who make awesome contraptions with lasers show on YouTube, but I'd frankly rather not get arrested.

Therefore my questions are:
Is possible to have a compact collimator that would actually create a rough beam from, say, one of the high luminosity LED's? Just narrow and divergent enough to create the effect on 10-20 meters.
If the former is at all possible, would a beam of sufficient brightness (like a high luminosity LED) scatter and be visible without introducing smoke (in dimmed stuffy room), like a high power laser?

So just to reiterate, I'm not asking "can I make a laser out of an LED", rather can I make something that would look like a video game laser weapon and be relatively harmless (not permanently blind people).

 

[phinds]

So just to reiterate, I'm not asking "can I make a laser out of an LED", rather can I make something that would look like a video game laser weapon and be relatively harmless (not permanently blind people).

Uh ... so you want to temporarily blind people? [sorry, I couldn't resist].

 

[szopaw]

Uh ... so you want to temporarily blind people? [sorry, I couldn't resist].

Not police helicopters anyway

 

[berkeman]

To give a little idea for what I'm aiming for: I want to make a prop laser gun. It doesn't have to actually do anything, but I've decided it'd be awesome if it did. I could use a 2-5W blue laser diode like some people who make awesome contraptions with lasers show on YouTube, but I'd frankly rather not get arrested.

Therefore my questions are:
Is possible to have a compact collimator that would actually create a rough beam from, say, one of the high luminosity LED's? Just narrow and divergent enough to create the effect on 10-20 meters.
If the former is at all possible, would a beam of sufficient brightness (like a high luminosity LED) scatter and be visible without introducing smoke (in dimmed stuffy room), like a high power laser?

So just to reiterate, I'm not asking "can I make a laser out of an LED", rather can I make something that would look like a video game laser weapon and be relatively harmless (not permanently blind people).

Welcome to the PF.

To see any light beam, you will need to use some sort of smoke or dust field. And it's good that you want to create the beam with simple LEDs and not moderate-power lasers.

 

[mfb]

Everything that generates a visible beam without smoke (or similar) is too powerful for a toy.

 

[Opus_723]

I have a <5mW green laser which you can't see in direct sunlight but produces a spectacular beam at nighttime. You still have to be careful not to shine it at someone's face, since it will produce temporary blindness. However, <5mW (which you'll see designated as class IIIA) is legal to use outside in the U.S. (mine was sold as a pointer for stargazing) and it shouldn't do permanent eye damage if the person reflexively closes their eyes (I would NOT test this though!).

Not really suitable for a toy, but a responsible adult can certainly use one to dramatic effect.

 

[szopaw]

Everything that generates a visible beam without smoke (or similar) is too powerful for a toy.

Probably true, certianly for lasers. Nevertheless, I'm still wondering if you can build a handheld non-laser light source that could give you the same effect as sun rays in musty rooms. I know the sun can do it, you don't even need smoke, just some dust an humidity. Hence my question of how bright does it have to be to give the same visible effect.
At least I know that anything as or less bright than direct sunlight will not permanently blind someone, unless on purpose.

Welcome to the PF.

To see any light beam, you will need to use some sort of smoke or dust field. And it's good that you want to create the beam with simple LEDs and not moderate-power lasers.

I'm running on the assumption that a relatively stuffy room (like at a cosplay convention) would be dusty and... moist enough, same way you can see sun rays in certain conditions. So again, it's not the matter of principle, it's "can I build that".

I have a <5mW green laser which you can't see in direct sunlight but produces a spectacular beam at nighttime. You still have to be careful not to shine it at someone's face, since it will produce temporary blindness. However, <5mW (which you'll see designated as class IIIA) is legal to use outside in the U.S. (mine was sold as a pointer for stargazing) and it shouldn't do permanent eye damage if the person reflexively closes their eyes (I would NOT test this though!).

Not really suitable for a toy, but a responsible adult can certainly use one to dramatic effect

Hence why I specified not wanting to use lasers. I know THOSE can give the effect, but it's too dangerous, for everyone.

 

[DaveC426913]

What if the gun spewed smoke/vapor that made the beam visible?

Nah, that'd look dumb.

 

[berkeman]

Remember those old air ball bazooka things back in the early 60's? There was a rifle version and a pistol version. You pumped them up and then shot out the air ball to knock over cards and such a ways away. And remember when they put smoke in them, they fired out a smoke ball that flew across the room.

I wonder if something like that could be cool. Do the light beam just right so it looks like you're shooting a fireball across the room...

Searching for images of that old thing. Anybody remember what it was called? Probably made by Wham-O or similar...

 

[berkeman]

Hah, good old Google Images! Found it:

1960's Wham-O Air Blaster

https://s-media-cache-ak0.pinimg.com/736x/99/eb/6a/99eb6ab1ffeb07fef1d3030ddaf055bc.jpg

 

[davenn]

that was educational, Berkeman ... never heard of that toy

 

[sophiecentaur]

Amazon sell the Airzooka, which is good fun. I have bought them for my kids and grandkids. You don't need the smoke - just the invisible vortex that ruffles peoples' hair and biff them in the face.

 

[sophiecentaur]

@berkeman: you are just a big kid!

 

[DaveC426913]

These are still for sale. But they are breech-fired with a strip of rubber.