Powering 28 50mw lasers how do you do it ?

:wtf:I am trying to create a virtual box with a bunch of lasers...i have two of such boxes and i would like to have one central power supply for all of them along with a on/off switch. I was looking to buy the 50mw 532n green lasers from dealextreme (HERE is a LINK). What else aside from the laser module would i need to get this application up and running. I must mention that i would like this to be constantly on for probably 12h at a time if not more. im not quite sure of what else to ask as my laser knowledge is still a bit shady...:wtf:

Twelve hours? You're going to need a serious heatsink.

What are you doing?

-Trevor

Have you ever seen the gogo dancer little square stages (or chicks dancing on speakers..) i want to build two 5x5 foot cages that would surround these girls and instead of every other bar id use lasers. The lasers need to be strong enough to be visible in club/bar like lighting environment, easy to turn on and off, and be able to sustain 12h/day of use. How would i accomplish that if at all...

essentially something like this ... Laser Table... minus the fog since we already have a fog machine and also id like to be able to see the lasers without fog. The metal bars on the side would prevent anyone from looking at the lasers straight on.

First of all, 50mW is pretty dangerous to be shining up around dancers.

- At the very least, I would suggest pointing them down from the ceiling as opposed to up from the floor. My logic being that people look down more than up.

- However, I think you also need to cut back the power. 50mW is just way too much to have in that sort of environment. Go with 10mW, and just introduce the tiniest bit of fog into the environment. It doesn't even need to be thick fog. You can have "fog" that is essentially imperceptible (you won't notice cloudy air), but it will still be enough to cause a 10mW green to show up, and quite well.

Finally, the power issue is pretty easy to solve. If those modules need 250 mA, then you need a 250 x 28 mA power supply. Simple math, that's 7A.

Look for 3V 2A AC power supplies. Grab 4 of them, they're probably $5 or so each. Attach 7 modules in parallel to each power supply. Get a heatsink for each laser. You should be all set.

But seriously, go with 10mW, or even 5mW.

If I screwed every module in aluminum sheet would that count as a heatsink for the lasers? And one of questions still remains how do u hook up those four 2v supplies to one switch flawleslly ? Wouldnt it be easier to get an 8v ps and hook up all of them to it? Or two 4v and have each cage on their own ps...
Sorry if I sound dumb or ignorant im really trying to fully comprehend the whole concept of lasers right now and how it would integrate into my application.

reddyfire said:

If I screwed every module in aluminum sheet would that count as a heatsink for the lasers? And one of questions still remains how do u hook up those four 2v supplies to one switch flawleslly ? Wouldnt it be easier to get an 8v ps and hook up all of them to it? Or two 4v and have each cage on their own ps...
Sorry if I sound dumb or ignorant im really trying to fully comprehend the whole concept of lasers right now and how it would integrate into my application.

Click to expand...

Huh?

No 2V power supplies... no 4V power supplies.

Get a ___3V___ power supply. If you can find one that does 8A, then you're set. That might be more difficult though (definitely not impossible, just not as easy as finding 2A supplies, which are everywhere).

1 switch? Depending on your form factor, it could be as simple as a wall switch, properly terminator in a junction box, or even simpler - a power bar.

I am actually not sure if a 5mW green laser module needs heatsinking. I made that comment without really thinking about the fact that at 5mW, the IR is probably just a 100mW diode. There might be enough surface area on the module itself to dissipate all of the heat produced, without a heatsink. I'm sorry that I don't have a better answer for you on that.

Metal bars or not, It's not going to be a good idea to have someone inside a cage of higher powered laser beams. People are going to want to touch the beams, so are the dancers, or maybe someone will spray some water in there, and someone is going to get blinded in the process. You might get sued for it.

The laser table you linked to was made with plain ol' 5mW red lasers, not any higher powered ones. Those are safe, and if you use 5mW green lasers they will look at least twice as bright at 5mW, and especially with fog. You should probably just stick with 5mW green lasers.

Finding a power supply that will power all the diodes at just 3V might be tough. 3.3V power supplies are more common (like these). They'll probably still work fine for those laser diodes. Just splice an old AC power cord from a computer power supply, and connect the lines to the AC input of the power supply. To make things even nicer, you can buy an AC switch and use that, but make sure its AC current rating is higher than the power supply's current rating. Be sure to use heat-shrinkwrap and hot glue to make things more touch-safe.

3.3 volts is more common indeed, and some may be adjustable a bit if you really want to go for 3.0, although its not required for these modules. There is no reason you cannot use several power supplies if you can't find a single one that provides all the current.

I think heatsinking will be the biggest issue though. A simple sheet/pane of aluminium wouldn't cut it for CW operation with this many lasers on it, you'd need to make some fins, or use a very large plate.

so essentially with two 3v 4a power supplies 28x10mw green lasers 1/4" thick aluminum sheeting with all the lasers screwed into it and a plexiglass pane over to make it "touch safe" i would accomplish my project ? that's what i understood so far....anything else i need to buy/get/think about ?

If you are lowering the Laser module to a 5mW-10mW Green
Laser the Lower powered Lasers will draw less current as a
result.
You can then recalculate your total power requirements as needed
by the lower (and safer) 5mW Lasers..


Jerry

lasersbee said:

You can then recalculate your total power requirements as needed by the lower (and safer) 5mW Lasers..

Click to expand...

OP, disregard that. The 5mW modules you're looking at draw 250mA. You're good.
$7.29 - 5mW 532nm Green Laser Module (3V 11.9mm) - Flashlight Parts and Tools

maybe im blind but i cant seem to find a 3v 4amp power supply to drive these lasers...i found the 10mw green lasers here but no signs of power supplies. also for 14 parallel connected lasers at 10mw will i still have the heatsink consideration in 1/2" aluminum sheeting ?

rhd said:

OP, disregard that. The 5mW modules you're looking at draw 250mA. You're good.
$7.29 - 5mW 532nm Green Laser Module (3V 11.9mm) - Flashlight Parts and Tools

Click to expand...

I would highly doubt that a true 5mw Laser....
would have the same current requirements as a 50mW Laser...
Perhaps the 50mW laser is not 50mW... or the 5mW Laser
is not 5mW...

That's like saying a 25 Watt bulb uses the same current as a
250 Watt bulb...

The pics of the 2 DX Lasers are identical and I would think they
kave the same or similar outputs but the 5mW is aimed at the US
market to get under the FDA radar...
Even a reviewer stated the 5mW Laser was putting out more
than advertised...


Jerry

Jerry don't forget, typical "5mW" lasers without APC are anywhere between 1mW and 30mW.
They all have that same 250-300mW pump diode, and it is not uncommon for them to draw even 300mA, (after a little potmod).

For 10mW green, better to do 4x7 series-parallel with a more common 12V 2A supply.