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ArcticMyst Security by Avery

The Lizard laser ( 445nm labby )

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So I decide it is time I begin my 2 W 445nm build. I had this spare cpu heatsink ( 1336 socket ) laying around, so I thought, why not turn this into a massive heatsink for a 445 diode? I then sent the hs to Pontiac5 for the cost of shipping both ways and he drilled it for no cost. Just letting you know how kind the guy is :) Yes it might be easy for some to make a simple hole but I heard copper is difficult to work with, so, thumbs up for this guy :) Here's how it was before and after it was machined.

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Today, with the help of some friend and my dad, we worked on something to hold the heatsink in place and is quite steady. I got a lot of pics since it was something I came up with and found it quite strange to do, but it turned out to be very efficient. My dad had a workshop in our basement years ago, with lots of tools, so it was a piece of cake for him to cut me a fine block of wood to mount everything on it. We used 2 mounts to hold the HS so it wont move forth and back and 2 other plates which fit between 2 of the heatsink fins ( that keeps the heatsink from moving up and down. In fact, the heatsink ended up staying on air ). Finally, with the use of some random sandpaper, here's what the setup looks like.

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videos:



Since my machining skills are not that good, I let my friend drill the wood and plates so we could attach the screws. Now the tricky part is on me, to find an efficient way to feed the diode ~1.8 amps with an input of 12 V.Since this laser will have no duty cycle, batteries won't be efficient and will drain very fast. The psu I will use can deliver up to 5 A and has an output voltage of 12 V as I said. I need to drop that voltage to ~6 V so I can use some kind of driver with fixed current. Now this is where I need some help with. I would prefer to do with this cheap components that I can get at a locale store ( lm317, resistors etc ). Please let me know what you guys would do accomplish the aforementioned. If you have a good idea on a driver as well, that is more than welcome too. But for a start, I need to get rid of those 6 Volts :evil:
 
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Trevor

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Re: Blue Destroyer ( 2 W 445nm )

I like it. Reminds me of this guy:

frilled-lizard500.jpg


:D

-Trevor
 
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Re: Blue Destroyer ( 2 W 445nm )

Not the best way to mount this piece of crap ( in terms of shape ) heatsink, but hey, you don't work with such things every day, plus I had no more ideas :(
 
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midias

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Re: Blue Destroyer ( 2 W 445nm )

You could sink a few LM317s in parallel with good heatsinking and balancing resistors. But your PD will still be huge. You should also be able to use you +12V as pwr and +3.3 or +5V as gnd to lower your PD. If I was to go linear I would get a T0 247 package but I don't like when things get warm.
 
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Re: Blue Destroyer ( 2 W 445nm )

:drool:


What driver you'll use?
 

Trevor

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Re: Blue Destroyer ( 2 W 445nm )

Not the best way to mound this piece of crap ( in terms of shape ) heatsink, but hey, you don't work with such things every day, plus I had no more ideas :(

It was a compliment. :D

-Trevor
 
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Re: Blue Destroyer ( 2 W 445nm )

I recommend a couple of these in parallel. I've done some tests with a 445:

10 min at 9V: ~43C temp rise on the hottest part (IC case); ~900mA supplied; ~500mA drawn.
10 min at 12V: ~52C temp rise; ~900mA supplied; ~370mA drawn.

The startup is smooth (checked on a scope), but it won't hurt to add a filter cap. The efficiency is about 85% compared with the 35% you'd get with a linear driver.

If you still want to use a linear driver, any of the LM series would be fine, but you'd need a fan-cooled heatsink, and it would help to put a power resistor in series with the diode to drop some voltage.
 
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Re: Blue Destroyer ( 2 W 445nm )

How necessary is a small piece of aluminum on the IC part? These seem to do the work but I don't really want to wait for the parts another 2 weeks :( Thanks for your input btw.
I recommend a couple of these in parallel. I've done some tests with a 445:

10 min at 9V: ~43C temp rise on the hottest part (IC case); ~900mA supplied; ~500mA drawn.
10 min at 12V: ~52C temp rise; ~900mA supplied; ~370mA drawn.

The startup is smooth (checked on a scope), but it won't hurt to add a filter cap. The efficiency is about 85% compared with the 35% you'd get with a linear driver.

If you still want to use a linear driver, any of the LM series would be fine, but you'd need a fan-cooled heatsink, and it would help to put a power resistor in series with the diode to drop some voltage.
 

Giface

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Re: Blue Destroyer ( 2 W 445nm )

Here's my solution to 12V and 1.8A:

18V 5W Cree Circuit Board for Flashlights (16.8mm*5.5mm) - Free Shipping - DealExtreme

You will need to solder a 0.50 Ohm resistor on top of the 0.20 Ohm sense resistor. That will give you around 1.75A. I've built several like this with no problems to speak of.

Oh, I also change the output wires on the board to silicone leads.

Dave

The driver I'm using is the same as the one you linked, but has a pot on it and the resistor was replaced. That can give me up to 2.1 A I think, which is not safe for the diode. I don't think I have any 1/2 ohm resistor around but if you say it works, then it should :) And 1.75 A is pretty much what I want, so I might give it a try in the future :D Thanks

So now what I'm gonna do is use 3 of the 5404 diodes and the 1 ohm 5 W resistor. That should give me a very close to the diode's load ( probably even less ) so it should be ok :D
 
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Re: Blue Destroyer ( 2 W 445nm )

UPDATE!!!
I finally finished this thing. Glued the driver input leads with some tape. Not the best way to keep things in place in a professional way, but it works :) I'll let the pictures do the talking.

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~Beamshots~

This one is with ISO 800 and no LT exposure
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Notice that this one is ISO 1000 and no LT exposure. The purple is pretty noticable compared to the first picture.
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The next one has an exposure of 1 sec and ISO 64.
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2 beamshots at 2 and 5 m respectively.

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The psu is a chinese power supply which provides 12 V and up to 5 amps and is very neat for diy projects. ( Benm suggested this psu, thanks man :) ) I found the IC part of the buck driver rather getting rather hot and impossible to touch after ~1 minute. You can see the small piece of aluminum mounted on the IC. In fact, that driver was made by lazeerer and it currently provides 1.75 A to the diode. So the output is nowhere near 2 W, but anyway it looks like a 2 W build :D :D ( thanks to you too, lazeerer :D ). Considering I'm using a 445 AR glass lens, what do you estimate the power to be? The current drops to ~1730 mA after some time but is quite stable overall. Lazeerer told me that 12 V is no problem for the driver but I have a hard time believing this(no offense), as I can't touch the cube of aluminum after some time. Also, the heatsink felt warm after ~10 min of runtime but it seems to dissipate the heat quite well. These heatsinks were made for higher wattage amounts anyway. There was no way to keep the fan behind the heatsink because then I would have to come up with another design to keep the hs in place. Anyway, I might add some more heatsinking on the IC of the driver later. But for now, that is all. Thanks for reading and I hope you like it :D

Peter
 
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