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Building Ugly: yet another 1W 445 (pics)

Canuke

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Sep 18, 2007
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After whetting my appetite with a repurposed Darcy Metal Gear build (that pulls so much from 3 AAA's that I had to track down some NiCD's to bear the brunt of it), I started looking at options for a 445 build. While Jayrob, Flaminpyro and others showed us plenty of host options, I decided that I would examine the prospects of repurposing a PGL-III-C greenie with a dead driver I have sitting around.

Here is the host.
img0130ed.th.jpg
img0131hi.th.jpg


It shows the scars of a retaining ring that seized up in what I presume was excess paint or anodizing at the mouth, that I eventually extracted by cutting it up with a Dremel. Suffice it to say that I learned a lot about how to disassemble things properly from this little struggle. In any case, it nevertheless held promise for my goal, which was to build a 445 with some staying power.

Side goals were to fully preserve the original FDA safety mechanisms of the host, which include a key interlock, shutter and butt plug (whatever that thing is called :)

My first step was to call in reinforcements, in the form of a Jayrob custom heatsink, machined to match the dimensions of the main 532nm module and set up with a Microboost maxed out with Jayrob's "Hot" option. The original module is the one with the brass section.
img0132jq.th.jpg


Since there was a quite large volume of metal, Jay and I elected to simply mount the driver at the back end of the sink and drill a channel through the center to the top where a standard Aixiz module would sit.

img0133qt.th.jpg
img0134m.th.jpg



Stage 1: assembling the sink and diode. I installed my waiting module with 445nm diode into the sink, wired it up to the driver, checked connections nd hooked it up to my bench supply which has variable maximums for voltage and current. With a 3.9V max, I elected to vary the current for testing.
img0135iu.th.jpg



With everything set up, I turned the current up to a few hundred mA, just enough to get it lasing, and -- flicker-flicker BRIGHT dead. :eek:

I yanked the current back down. Dead already? Checked everything, turned it back up. A sickly purple glow told me everything I needed to know -- the diode was fried. Aw, dammit. Time to log into LPF and see if daguin's got any more of these lef----

wait a minute. Purple? I applied power again. That's not 445, it looks like 405! I realized that I'd just shoved about 1A through a spare PHR .

:oops: I thought I'd already swapped in the new diode.

So I just needed to fetch the 445nm and install it in the module. But where was the blasted thing? I had it in my head for weeks that it was in the module! OMG, what happened to it, did I throw out the little envelope Dave had sent it in? Oh No, WHERE IN THE NAME OF DAGUIN IS THAT 445NM -----

img0136ns.th.jpg


oh there it is.
:whistle:

Carefully install it in the module, and once again set things up in the sink. Double-check all the connections, discharge the driver caps, solder. Apply power, and --

img0137gt.th.jpg


... all is right (and rich blue) in the world!

The first design assumption had not passed muster. My Darcy setup, which likely tops out around 300mW with freshly charged batteries, seems hardly to warm up the heatsink, which is roughly a 1" by 1/2" cylinder. I had it in my head that something over 2" long would be able to soak up that heat for quite a while.

Not so. Run at full power, even this sink became too hot to hold after about a minute(3.8V @ 1.5A into the Microboost). The host would help bleed it off, but even so I was still blown away by how much power was involved here.
img0138q.th.jpg


As I said to Jay, I'm going to need a bigger boat -- er, set of goggles. I have a pair, but they are out of their league here. Anything caught in the beam within five feet was set to smoking in seconds. More than once my wife asked me what was burning as I labored away in the lab :eek:

This test target started smoking before I even brought it to full power -- and burned right through before I could snap these shots.
img0142dh.th.jpg

img0144w.th.jpg
img0145zx.th.jpg


All that remained by this point was installing it into the host.

I elected to retain the original main switch rather than try to match something else in. After an abortive attempt at trying to epoxy it onto the plastic mounting bracket in its original position, I elected to strip the components off the dead driver board and remount it there, which had the advantage of being the original mounting setup.

Here's the assembly, showing the original plastic mounting hardware.
img0151h.th.jpg
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See that stranded wire splayed around the side? That's the first huge flaw in the setup as it now stands. Positive power was provided for in the original setup, but drew the negative power off the case via the aluminum cap (seen in the pic with the blue pads). Here my limited knowledge brought me to an impasse: how do I attach the driver wire to the case? Nothing but aluminum as far as the eye can see -- solder won't stick. I ended up attaching the negative wire to the aluminum cap (minus the blue pads in the pic) with some electrical tape, and bolstering the connection with some foam compressed between the switch board and the new sink.

As this needed to have some steady pressure applied to that electrical tape to ensure a decent connection, I had to retain the sink with pressure. And here we come to the second major flaw in this build -- no retention solution. With the host threads unusable, I had no immediately available method of retaining the sink other than this hack:
img0152tm.th.jpg


Yes, that's a length of wire wedged into the threads.

And if that weren't enough, once I'd addressed all the glitches that were my fault, the host decided to throw up one of its own: the "butt plug" began malfunctioning. After some irritated searching for potential opens around the driver, I finally tracked it down to the host, and decided to sacrifice the "butt plug" safety with a soldered short.

Once all that was done, however, the beast roared to life. Here are two shots comparing it with the 300mW Darcy build with freshly charged batteries.
img0155lr.th.jpg


The wooden bedframe which was the target for the second shot was smellably smoking after scant seconds, from four feet away.
img0156j.th.jpg


Here are some final build notes:

An unprotected LG Chem 18650 cell is able to handle the average 1.5A pulled by the Microboost. This current pull gets up to around 2A before the driver starts flashing, and then drops to half power. Don't be running it by then, that's 2A at 2.2V and will kill your unprotected 18650.

I found out that feeding the Microboost at 2.2V (from my bench supply) allowed me to turn the current as low as 10mA, taking it down to Class IIIA levels, and it still lases.

A big thanks to jayrob, who took the time to include some notes and instructions with the sink, in particular the polarity -- which is more than I could say for CNI, hence the availability of this host :p

Finally, I would like to Ask The Experts some advice on solving these remaining issues with this build:

1. How to reliably wire up the driver negative to aluminum (specifically that aluminum cap)? I've heard that aluminum is solderable, but it's beyond my limited skills. I don't recall how it was done with the original driver; I suspect a direct connection, since the driver sits in it. There is a hole in the cap, I've thought of using a screw for a tight mechanical connection, or a clip.

2. Ideas for a retention solution? I originally planned a set screw, but I don't know where such screws can be had (Home Depot?) and I think the housing may be too thin unless I can tap a very small hole. (By way of note: the set screw Jayrob used in the sink, fitting a 1.5mm allen wrench, is probably too big). Most of the outermost threads at the host mouth are destroyed and unusable.

With solutions to those issues in place, this will be a finished build.
 





drevil

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wow that heat sink looks giant. I have been wanting to build a rpl style 445 build.

O and also gordn biersch= win
 
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Kevlar

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You can wire the driver negative by way of the diode case pin. Like this:
Bludiodeandboostdriverwiring.png


I had the same question when building my Ehgumus 445nm and he provided me with this picture. So it will be host negative, the positive end of the battery will go in first with the negative end of the battery at the tail cap.

Hope this helps, and anyone correct me if I'm wrong as I'm not familiar with this host. You stated in the original set up that the Positive power was provided for in the original setup, but drew the negative power off the case via the aluminum cap. I thought most green lasers are case positive.
 

Canuke

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Hey Kevlar,

Thanks for the pic, but the can pin was cut short on this diode, and Jayrob has already handled the wiring for the driver. All I need is a solution for the *mechanical* means of connecting the negative input to the aluminum cap.

I'm currently thinking of locating a short bolt and nut to go in the small center hole in the aluminum cap (the piece with the blue tabs on it in the above pics), and use that as a battery-style terminal.

I have no ideas yet for the retention solution, as the sink is currently only held in by that little bit of wire.
 

DrSid

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The pin (from Dave) is shorter .. but if you remove the plastic spacer, it is surely long enough to safely solder on it.
 

Canuke

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The pin (from Dave) is shorter .. but if you remove the plastic spacer, it is surely long enough to safely solder on it.

I had checked with jayrob before I began the installation, and he specifically said not to do that. As everything is working perfectly, I'll stick with this setup, and will probably use the nut-and-bolt solution for the driver negative wire connection to the case.
 
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1. How to reliably wire up the driver negative to aluminum (specifically that aluminum cap)? I've heard that aluminum is solderable, but it's beyond my limited skills. I don't recall how it was done with the original driver; I suspect a direct connection, since the driver sits in it. There is a hole in the cap, I've thought of using a screw for a tight mechanical connection, or a clip.

You won't easily be able to solder the aluminium. All the heat will be sucked away from the iron as fast as it can apply it! Not to mention it is difficult anyway, there are loads of pitfalls.

If you have or can get a tap and die set, you could thread the hole. Solder your -ve wire to a solder terminal and fix it to the sink with a suitable screw. This isn't the same layout as yours but you get the idea:

washer_01.jpg
washer_02.jpg


2. Ideas for a retention solution? I originally planned a set screw, but I don't know where such screws can be had (Home Depot?) and I think the housing may be too thin unless I can tap a very small hole. (By way of note: the set screw Jayrob used in the sink, fitting a 1.5mm allen wrench, is probably too big). Most of the outermost threads at the host mouth are destroyed and unusable.

I'd maybe go for 4 small countersunk screws spaced equally round the host, screwing it to the sink. This can actually look really cool. Again you will need a tap or die (I forget which is which) to thread the holes, and a drill of course to make them. Carefully!... since you do not want to drill through into your driver board!

I'm by no means expert, this is just my humble take :)
 

Canuke

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micksterbs, thanks for the advice. I was thinking along similar lines for retention, by drilling and threading holes in the thicker ridged part of the host instead of the handle. I plan to look into this over the weekend.

Regarding the negative driver input, the solder terminal (that ringed contact) is a good idea. There's room on either side of the cap, so I might be able to use a nut-bolt combo instead of threading that hole (that cap isn't very thick), and perhaps a lockwasher for contact.

Lastly: I just noticed that the images are just the thumbnails, without links to the bigger pics on Imageshack :p I'll try to fix that later.
 
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Very cool. I cant wait to get my 445 out of the test heat sink and into a real host.
 




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