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Cheap 5mW units from China

Peet42

Peet42

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I just wanted to draw your attention to these:


Even allowing for import taxes, they're cheaper than building one.
 





ive gotten a couple of these. they are NOT the leadlight's. you cant get the head off easily or without messing up the finish. i tried. they are good if you want a 5mw laser, but not for modifying. IMO.
 
but not for modifying. IMO.

So do they have a fixed-value driver or does the driver have a pot? If these are just a throttled-back PHR (like people have found on Ebay in similar hosts) then theoretically these should be able to be cranked up significantly (although probably not so easy to focus without removing the head)...
 
not really what i meant. i have no idea what diode is used in these. the ones i have are 532nm. you just cant get the cases open without F*ing them up. i did cut one up and the inside diameter is smaller than an aixiz module if i remember correctly.

http://cgi.ebay.com/Stylish-5mW-5-m...5|66:2|65:12|39:1|240:1309|301:1|293:1|294:50

here is a close pix
Green_Laser_Pointer_Pen.jpg
 
hey peet can you ask your company which diode they use :)
 
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They're not really "my" company (I'm in Scotland!) but I have bought stuff from them before and the quality is good. I ordered one of these pointers the day I posted the link, and it's supposedly in transit now. I'll post a review when I get it.

I have one of the green lasers pictured above - they are "double pumped" units containing two infra-red laser diodes and some sort of frequency-doubling crystal to produce the green beam. Or, at least, mine is... I bought it three years ago or so, and at the time single green diodes weren't available.

I'm wondering if the Chinese "violet" laser pointer is just "double-pumping" a visible red laser? It would explain why it's so much cheaper than any others that I've seen. It looks to be in an identical casing to my green unit, apart from the paint finish on the cap.
 
It's definitely a 405nm diode, the question is which one and running at what current... I don't believe it's even possible to crystal pump a red to get violet at 405nm (although I could be wrong, just never encountered that setup).

IIRC, there were some low-buck KES based violets at really low (5mW) outputs, but currently there are a ton of PHR-based pointers out there cranked down to operate barely above threshold, if this is one of those it might be a find, providing you can get at the driver and it has an adjustable pot.
 
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BrewCityMusic said:
It's definitely a 405nm diode, the question is which one and running at what current... I don't believe it's even possible to crystal pump a red to get violet at 405nm (although I could be wrong, just never encountered that setup).
Click to expand...

Most likely it's not possible, and if it were I don't see why it would be cheaper.And yes those aren't meant to be dissasembled.I tried opening one up with the "drilled wood and vicegrip" method that just messed up the black paint and finally succeded with the "butcher it on the lathe" method :)
 
their reply really tells us nothing. most wholesalers don't know the products they sell inside and out. they just know how to read the vague documentation that they were sent. besides most cheap-o products don't come with detailed specs anyways. when was the last time you went to store and bought a red pointer and it said what diode is used.
we just need to order one, tear it open and research. i've got a feeling that it probably is NOT a PHR-803T diode anyways, but only one way to know. i ordered a couple of the green lasers like the ones in the pix i posted above. ill post the results when they arrive. now we need a 405nm pointer to use as a guinea pig.
anyone?
 
It's Heeeeeeeeeere...

OK, well, it just arrived. The packaging is a bit "cheap" and they omitted to include both batteries and instructions, but as it seems to have been cheap enough to avoid any import taxes I'll forgive them that. ;)

It's physically identical to the green unit pictured above. (That means the componments are "potted", so there's little scope for customisation...) It's a fraction lighter than my green unit, and doesn't have the non-slip grip on the end. But, all-in-all, it seems to be very solidly made. Coming from China, of course, there's no "warning label", so that's one fewer source of information... It just has a small silver sticky that says "CE FCC Made in China".

The beam is narrower than from my green laser (about 4/5ths the diameter) and isn't "optically" so bright, but the latter is to be expected. You really get an idea of the power when you shine it on something that fluoresces, though, like the cap of a highlighter pen. The resulting spot (in the colour of the cap, i.e green, pink or yellow) is almost too bright to look at.

One thing that caight me by surprise was the fluorescent nature of coffee whitener... I shon it onto the top of my mug of coffee - this resulted in a white spot, yet still a blue reflection on the inside of the cup. Weird.

Anyhoo. The only suggestion I could make for boosting the power would be to boost the input voltage slightly... The batteries fit in the "pen cap", and at the moment I'm using two 1.5v Alkaline units for a total of 3v - it should be possible to mill a metal tube to replace the cap and let you put in three NiMH batteries at 1.2v each for a total of 3.6v. I don't know if a 20% over-voltage would kill it, but it's an experiment you could try first on one of those $8 green pointers as the battery cap is interchangable.

If you just want a pointer and aren't out to customise it, I'd recommend it. Enjoy.
 
Just because it looks like the one in a picture doesn't mean its been pot modded. There still could be room to adjust. If it even has a pot at all. And about adding more batteries before you get into milling and all that can you tell if your driver has a voltage regulator?
 
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