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Making a Holiday "STAR SHOWER-TYPE" display

PenJet

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Have purchased the cheap overseas RED/GREEN "Christmas Laser Lights" in the past. Every time they typically work for a few weeks, and then stop.
I have scavenged the parts from one or two, and am looking to build my own laser light from the parts.

My wife wants Blue and Green lights, or just blue.

I have seen laser pointers with BLUE or GREEN for about 4bucks or so online. I don't know the deeds, but I imagine they must be sub 5mV?

With the refractor lenses scavenged from the old lights, and a blue and green laser pointer, is there a way to create my own B/G laser lights with a generic AC to DC converter set to approx 4.5 - 6V+?

Any tips?
 

ElectricPlasma

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Those modules are terrible quality, and I'm betting that the driver is probably built into the logic board for the whole device.

If you want a cheap, but working, laser module then check out fasttech for "5mW" 532nm modules. I use them all the time, and get around 100mW average with adjusting. For 5$ you can't beat it.

If you want quality drivers and diodes from the USA, check out DTR's laser shop. His work and service is always above satisfactory.
 

diachi

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Did I read this same thread/question somewhere the other day...?

Got your units wrong, it's 5mW not 5mV (milliwatts, not millivolts). Anyway...

Yes, you could use pointers (Better off with OEM modules IMO, easier to integrate). Those cheap eBay pointers and such aren't necessarily <5mW though, my cheapo pointer does >90mW. Something to consider. That's enough power to cause eye damage if something goes wrong. The quality is also terrible at those prices.

You could just replace the green/red lasers in the original housing with blue/green and get it working that way. Or take the guts and put them in a new housing. The optic in these is usually a rotating diffraction grating or two, no refractive optics involved in any that I've seen - outside of the lasers themselves.

Does it get cold where you are? 532nm green lasers don't generally like being cold - it's possible you'd need a source of heat to keep the green laser happy if you went for 532nm. If that'll be a problem you could go for a 520nm laser (still green, just a different shade). Those are a little more expensive but don't really have issues when they get cold.

You'd maybe need a source of heat to keep out condensation/frost anyway...

I personally would just buy something off the shelf ... you'd end up being liable if something you built caused eye damage or some such. If it's off the shelf, then whoever sold it/manufactured it would likely be liable.
 
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ElectricPlasma

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Yea, that's a good idea. That's what I did at first, started off with buying a couple lasers from Sanwu and then as I got more confident I started dealing with the laser components. They're fragile pieces so it's a good idea to have a basic knowledge on them before you start building.

I'd recommend a Sanwu pocket series laser, I've got the 445nm model and I love it, great sturdy SS material and nice quality from Sanwu as always. :D
 

diachi

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I'd recommend a Sanwu pocket series laser, I've got the 445nm model and I love it, great sturdy SS material and nice quality from Sanwu as always. :D

That'd be a waste of a perfectly good Sanwu Pocket to use it in a star projector if you ask me. :eek: :eek:

They are nice lasers ... I have a 445 on the way to go with the 650.
 
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ElectricPlasma

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That'd be a waste of a perfectly good Sanwu Pocket to use it in a star projector if you ask me. :O :O

They are nice lasers ... I have a 445 on the way to go with the 650.
I should've been more clear, I meant as a starting-out laser. :p
 

CDBEAM777

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Hmmmm ??? I bought two different brands.....One is OK...the other got returned !!
Well...the price on these has tumbled !! The housing on the one I kept is very robust !!
Let's see how long it runs !!!

Yea....the power is not what I am used to !!! But then, all things considered... that is likely a good thing....cause ya know...If I built one....I would want a watt of green....and a watt of red !!!

Then...Some "Bozo" could sue me cause they damaged their eyes....look'in at my Christmas Lights !!!....Naa.....some things are better just to buy !!!

Now...a cheap, text programmable Laser projector.....where the projector unit stays in the house....and the display is fibre optic coupled to the " Projector Head "...outside !!!
That way....the " goodies" are kept outa the elements....and secure from theft !!!

Just think what Non-PC messages one could flash the neighbor's !! EEeeeee...well....maybe not a good idea also !!!...consider'in all the " Nut Job's" that are out there !!!! ( Yea...and inside the house too !!! )

Later....my Yuletide YingYang's !! Here we go !!! Another Festivus Miracle!

CDBEAM
 
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Benm

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Yeah, 445 would certainly be the way to go. You don't need to get an overly expensive diode though, any M140 diode will produce a lot of light at limited cost. Beware of eye safety with these things though.

I would generally recommend against 532 nm green diodes for this application: If you are placing them outdoors the cold temperatures may redcuce their output power to near zero if unlucky. This mostly applies to places where you can actually have a white christmas though, if you are in a more tropical area it could be just fine.
 

PenJet

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Thanks much all. (yes 5mW btw--sorry about that...was sorting through DC power units).
I would love to one day do the messaged and type display.

I guess I was looking for an inexpensive source for the blue or green laser modules that could slip into the existing heatsink and housing (and bypass the cheap control board that is inside).

I guess I revealed my total newbie foolishness (which I am) in that I believed that the visible spectrum blue and green at low power (which I thought <5mW) would be "eye-safe." Would I need to install some kind of pot or resistance board too? Would that harm the diode?

I do live in a pretty cold climate. I'd say Xmas is anywhere from -15F (lower with wind chill potentially) up through 40F. (Oddly on the old unit, the green module lasted longer than the red). It looks like the heatsink around one of the modules was larger than the other though too.
 
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Benm

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That is pretty cold indeed. Forget about the 532 nm lasers, they are unlikely to work (well) under those conditions.

Eye-safe is a very broad term. I think the limit for that would be 1 mW at most, as you will not damage your eyes by limited exposure. 5 mW is a limit based on the speed at which your eyes can blink. This is okay if your blink reflex is normal (eyelids shut in 0.25 of a second upon painfully bright light), but might be dangerous if your reflexes are slower (due to disease, drink or drugs for example).

As for replacing the existing lasers: It would depend on their form factor how easy it would be to swap them out. Afaik these xmas decoration things do not use 'standard' 12mm diode holders, so you'd probably have to change the diodes and driver circuitry.

This is not overly dificult for someone experienced with it, but if you've never done somethink like it before, and are not good at fine solderwork, chances are you will mess it up the first few attempts.
 




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