50mW Spirograph - does fast rotation negate the need for goggles?

[montymintypie]

Hi all,

Inspired by some of the cool spirograph projects I've found around the place, I've decided to create my own, Arduino controlled one, with saveable patterns etc etc... For this, I've grabbed a 5mW dealextreme module, and I'm going to pot mod it (don't lecture me on why not, I spent all of $3 on this The board looks identical from 5-50mW, so I'll assume it'll be fine) to around 40-50mW (I have an O-like 50mW for reference).

My real question is, a spirograph has rapidly moving circles and other patterns of laser light, rather than a concentrated beam. Does this fast movement negate the need for goggles when this is used? Specifically, if someone gets hit in the eye while the spirograph is running, could damage still occur? I'm a safety nazi with my 50mW as I don't have goggles, but this will be more of a party piece than a 'you get a 10 minute lecture before you use this'.

Thanks in advance for your advice!

 

[Trevor]

I don't have any math to back it up.

But... if I were in the room with that and knew it was 50mW, I would not want to get hit with it.

That being said, you biggest risk lies in a failure of the system and your mirrors stopping.

-Trevor

 

[montymintypie]

So, to be safe assume it's not eye safe? I might see how it looks, if it's acceptable at 5mW I might even just leave it at that.

 

[Trevor]

Yeah, if you're not sure always assume it's not safe.

It's acceptable at 5mW but you need to confirm 5mW of output and no IR leakage.

-Trevor

 

[chipdouglas]

you probably wont notice much difference of the patterns on a wall from a 5mw or a 50mw. the 50mw would be beneficial if you were using the spirograph to make beam shows/"time tunnels"

michael.

 

[montymintypie]

It's acceptable at 5mW but you need to confirm 5mW of output and no IR leakage.

Being a cheap laser, I doubt it's filtered. I'll salvage one from an old digital camera I have lying around and attach it.

you probably wont notice much difference of the patterns on a wall from a 5mw or a 50mw. the 50mw would be beneficial if you were using the spirograph to make beam shows/"time tunnels"

michael.

Ok, sounds like I might just keep it at 5mW then, unless I do plan to go to the more intense stuff... Thanks again

 

[JBTexas]

I'd expand on Trevor's first reply... if the system failed unexpectedly (likely enough- motors burn out) and the laser(s) "froze", there could be a recognition lag. Not enough time to look away. A possibly tragic accident. Especially if you were showing it off to visitors.

 

[montymintypie]

I'd expand on Trevor's first reply... if the system failed unexpectedly (likely enough- motors burn out) and the laser(s) "froze", there could be a recognition lag. Not enough time to look away. A possibly tragic accident. Especially if you were showing it off to visitors.

With that sobering thought, I think I'll keep it either pointed up away from eyesight or kept at 5mW.

 

[JBTexas]

You just indicated something... maybe if it was DESIGNED to only project at a high angle (ceiling, upper walls), and you kept people out of the beam paths.

After all, at laser shows and planetariums, they don't issue safety goggles to the spectators.

It is still a risk, though, and as it's been said, you only need ~5mw to make the patterns.

 

[montymintypie]

I think I'll make a proper judgement when I get the module - Here's hoping there's no need to pot mod it in the first place. If I do... Well, I think I'll keep it away from eye level.