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ArcticMyst Security by Avery

A140 diode low power build

Joined
Dec 3, 2007
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I wanted a 445nm laser at low power that could actually be used for pointing.
My favorite host for a low power side-button build is the Atlasnova red laser pointer. It is pretty easy to open and most of its components can be re-used for the 445 build. The host looks like this, classic slim <5mW "two AAA" pointer, its diameter is a little bit less than that of an Aixiz module.
hostx.jpg

frontuvn.jpg


The head is press fit into the barrel, easy to remove with pliers cushioned with some rubber or leather in order to protect the black finish.
Here you can see the original pointer's driver board. Note that there is a 5.6mm "can-type" red laser diode in there, not one of the "chip-on-pcb variety" found in most cheap red pointers. That's what I like most about the Atlasnova host: The brass diode holder can be re-used to mount the new diode into.
before1k.jpg

before2p.jpg


After pushing out the 650nm diode I put in the 445nm Casio LD, used a tiny amount of thermal compound to make as much as possible of the little bit of heat sinking the brass module provides.
Kept the original lens (plastic, uncoated as far as I can tell), should be able to hold up to the 445 diode at low power. The lens sits just behind the pointer's tip, focus is achieved by screwing the brass module into that tip.

I wanted the pointer to run on alkaline or NiMH batteries, so I used a step-up driver.
The driver board just fits inside the barrel and has enough space on its back side to mount the switch and spring. I simply glued the switch onto the PCB and used one of its legs to solder the positive contact spring.
The driver is set for ~280mA, puts out about 40mW. I expect the output to fluctuate quite a bit with temperature since the diode is driven just above lasing threshold.
after1m.jpg

after2c.jpg


The dot is not very pretty of course and that little brass holder gets warm when the pointer is used continuously but I think it could actually be used for pointing at reasonable distances.

Maybe one day one can get 50mW 445nm single-mode diodes at reasonable prices but until then this thing has to hold me over ;)
 





daguin

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Joined
Mar 29, 2008
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SWEET! My 50mW 445nm gets used more than any of my other 445nm lasers.

Peace,
dave
 
Joined
Dec 3, 2007
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After trying it out in the dark I like it more and more.
Here is a crude attempt at a beam shot.

beam.jpg
 
Last edited:
Joined
Sep 16, 2007
Messages
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Nice job.
What does the beam look like at that power?

When I was setting my "low power" 445 I started at 225mA and worked up from there. The diode would output only one narrow stripe up to ~50mW, then more modes would begin to appear. Right now it's set at ~150mW - the beam has one strong mode in the center and a couple faint modes on each side.

I do like having a lower power variant of the 445 much more than a Class IV. Its much more pleasant to play with.
 




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