$8 Ebay pointer becomes a burning laser!

[Kage]

Like may other members here, I couldn't resist buying a few of these cheap 405nm laser pointers off Ebay. Upon testing them, I was pleased to find they all output right around 50mW with a couple of Ni-MH AAA batteries.

That is enough to light a match with 405nm if focused to a fine point. The bad news is that these don't focus to a fine point. They seemed to be set roughly to infinity, one focused at 5 feet, the dot was too big to burn - but it did pop a balloon.

One of them was actually divergent, so I decided to use that one for a little experiment, that turned into a small project.

Pulling the end cap, revealed what appeared to be an Axiz style plastic lens!
I stuck a large screwdriver in to turn it, and found it was securely locked in place with some sort of threadlocker. That was disappointing.

So, I removed the module from the housing, using a small screwdriver as a drift punch against the brass module from the threaded end and forced it out the other end. The module is a cleanly made boost driver with a nice plastic holder to keep it secure.

I ended up having to heat the lens and module with a heat gun to soften the plastic lens enough to unscrew it - which ruined it completely. I carefully removed the remaining threadlocker from the threads and screwed a new Axiz acrylic lens and focus ring in it's place - it fits nice and snug - no need for teflon tape or a spring.

At this point it was already able to light a match. But I couldn't stop there. There was a pot I hadn't turned yet :eg:. Cranking the pot to max brought the power out to a healthy 65mW.

Since it was clamped in a vice and connected to a power supply at this point, I tried playing with the voltage supply, and sure enough it regulated perfectly from about 2.5V to over 4.5V, with the expected drop in current as V is increased. Obviously capable of being run from a Lithium cell.

Here is the final result of the effort:

3.5" of focusable, match lighting fun, operating from a single 10440 lithium :beer:

 

[Prototype]

Very nice work, +1 for sure. Have you considered putting the original end on it, with a bit of the interior ground down so it fits over an aixiz focusing knob, securing it in place with a dab of epoxy? That way it would look even more original

 

[lazeerer]

Awesome, Nice thinking. I really like how you made it your own and minimized the size of the pen to fit a 10440 battery instead of using spacer. :gj:

 

[Flaminpyro]

I like the look of it with the focus ring what it realy needs is a custom focus ring designed just for it
+1 for your idea of making it shorter and focusing the beam

 

[Kage]

Hey all,
thanks for the comments and generosity!

Very nice work, +1 for sure. Have you considered putting the original end on it, with a bit of the interior ground down so it fits over an aixiz focusing knob, securing it in place with a dab of epoxy? That way it would look even more original

It took me a minute to understand what you mean, but you know it does look like the focus ring could be pressed or made to fit into the end cap, and if the skirt were cut off at the bottom, it just might work. After I am done modifying a couple more of these, i'll give it a shot and post the picture if it works. Thanks for the idea - a rep for you too.
The next two units are going even easier than the first one. This time I started out by sawing through the barrel just below the label. By barely sawing until the blade breaks through, and doing this all around the outside until the piece comes off, the focusing lens is exposed without having to disassemble anything else. And the nice part is neither of these two lenses were sealed in place like the first one. They just broke loose with minimal force, leaving the lens intact. So, in most cases, it might require little else than a hacksaw and focus ring to make decent laser out of these!

 

[extremeodd]

Well I cut my ebay 405nm down a while ago but just now ordered an aixis module so I can have an easy to use focus ring. Kinda a pita to spin the stock one.

 

[Kage]

Here is the look with the smooth cap pressed on:

Here is the entire mechanical disassembly:

In contradiction of my earlier statement about removing the module through the lens end - Don't! My second attempt ended with broken-off coil and broken pot whilst attempting this. :can: Some are just too tight. Better to remove the threaded insert (brass colored) and PRESS the module out that end.
Also, the next one I did get out in one piece, would not output more than 50mW even with pot all the way up. YMMV!
At this point I would only recommend the focus mod, or shortening the battery barrel for single cell for who like the Lithium stuff. Far less chance of killing your laser!

 

[lazeerer]

Man this looks even better with the cap. I hope NewW*sh doesn't copy you now. :tsk:

 

[00Giorge]

Wow! Nice I have 2 of those I might have to try that, I tried to give you a +1 but I have to spread the love first.

 

[Ezcal]

Very cool build, I love the idea! +1 for a fellow Oregonian!

 

[IsaacT]

Blast! You beat me to it! I have a Newwish pointer that I took apart, and was planning on pressin the front cap on an aixiz knob....brilliant , shortening the pointer! Nicely done, nicely done! +1

I also found it difficult to say the least to remove the driver. I couldn't get it out of the threaded side, so I pressed the brass module out of the front, and then slid the driver piece up that way...I ended up with a snapped driver however :/

 

[deluminati]

What amperage is the driver circuit capable of? Might buy one of these just to harvest the module/driver.

 

[jakeGT]

one quick question... which way do the original AAA batteries go in? case positive or negative? and will it short it out on this style pen if you put em in wrong? i bought one off ebay too

 

[IsaacT]

When I put mine in at first I put them wrong way and it didn't harm it....IIRC tho, it is positive towards diode, negative towards back end.

 

[LtKernelPanic]

Nice job! I'm thinking about ordering another one to do the focusing mod for sure and maybe the battery as well. If you don't mind me asking how did you get the bass insert and the silver threaded piece out? I know you use the block wood trick to get the front cap off and could tap the back cap off with a long screw driver from the inside. Also was there a trick to getting the module and driver out without the button ripping the switch off or is there enough clearance where it'll just slide past?

Thanks and a +1 for a sweet looking mod!

 

[IsaacT]

LtKernelPanic: When I took mine apart, I used the aluminum rods that the Optical Sleds sit on inside DVD writers. I used them to push the brass module out with a vise. It was time consuming, but I find that pushing it out with a vice is the only way it will come out.