600mW 445nm 3x10440 build with gun barrel heatsink

Yay! I just finished my first build from scratch and I feel like an overexcited schoolboy.

I'm not an expert at this sort of thing. Constructive criticism is always welcome There are some things I would definitely do differently next time (list at end) but basically I am happy with it and want to share it!


Here is the stuff I used to build it. In the UK we have the lovely Maplin which I guess is like the USA's Radio Shack (do they still exist?) where you can buy really crappy "Rolson" 3xAAA LED torches "three for a fiver" kind of thing. The host betrays its poor quality by its clicky which is a bit coarse in operation. The housing is aluminium and quite thin and feels flimsy. Ah well. (Those wires on the driver, I took them off.)






This is a section of a massive 22-250 rifle barrel which I had lying around (as you do). It is stainless steel and it's soooo nice and chunky. It may not be the best heatsink metal but it will do for this build. I've turned it down at one end so that it fits very snugly in the head of the host without needing any other form of fixing. It's a bugger to get out once it's in but it is possible. I've also bored out the .22 hole to 12mm of course. (I wanted to leave some of the rifling intact as evidence of its origin but I needed more than a .22 hole all the way through. It could have been done, but it was waaaay simpler not to.)






This is the fabulous MicroBoost driver on a piece of Veroboard. I've isolated the centre strips from the outside ones with a 5mm drill bit and bolted a piece of fuse wire to the centre and soldered it to the driver. (Don't laugh at the size of my solder blob jumpering the "R510" to the pad on the PCB ). These drivers are tiny miracles (thank you drlava), and they are a complete bugger to work on at first if you are not so used to small stuff, like me. In the right hand pic you can see I've made (poorly) a tiny wedge of aluminium and stuck it to the 'thing that gets hot'(?) on the driver board. The original idea was to insert the whole lot into a piece of 12mm diameter ali tube (see second pic, above) but it was too tight a fit so I had to take a large section of the tube out. Copious epoxy to stop wires shorting, and give the whole thing some stability. (BluTak possibly my most-used solder helper )






Left: The driver in its very cut-down ali tube. I glued it to that 'wedge' with a 50/50 mix of epoxy and computer heatsink compound. The thermal bond does not seem to be fantastic but it is adequate. The wires are a little thick too but I was going for flexibility as much as anything else, all the thinner wires I had to hand seemed to be steel, and less flexible (I've now sourced some ultra-flexible silicone wire, it's fabulous). As you can see, the Verobard presses against the steel, so the case is the -VE (though it could have been done either way). The positive end of the battery capsule contacts the screw head.






I modded the 3xAAA battery holder to be wired in parallel (very simple mod: just connect the unconnected pieces at each end and remember to insert all batteries pointing the same way) and am using 3x10440 3.7V NiMh cells. They seem to work much better than 3xAAA in series.






The finished item. For scale, the right hand image includes our British Standard unit of laser sizing, the Oyster Card.






One more, and the obligatory beam shot .





Here's the power curve over 5 minutes. That weirdness at the RHS is me adjusting to 'just below max' because at max it starts to pulse after only a few seconds.




What I would do different next time

* Ultra-flexible wires
* Attach the driver to the main sink rather than a tube insert (this was majorly fiddly)
* Make a recess for the focussing ring - sticks out way too far.
* Account for the diameter of the wire soldered around the edge of the Veroboard. I didn't, and there is a tiny gap (just visible in the photos) between the end of the wide part of the sink and the start of the host body. To fix it I'd need to sleeve the sink down another mm. I think I'll put an O-ring in there when I can find one the right size.



Thanks for reading :beer:
Bruce

Nothing much to criticise Bruce....good build!

+1

Very nice gave me an idea for a future build. Adding to google notebook for future references

...what operating system are you running? Luminosity shouldn't look like that.

*wants to fix it*

-Trevor

Hey, great sofware Trevor. :gj:

I've got Windows 7 set to "look as much like XP as possible" mode because I can't stand all that Aero stuff. I suspect that's what's making it look weird to you -- it doesn't to me cos I've never seen it any other way

Actually I've been meaning to contact you about the software because I've some feedback and ideas. Is there a forum for it? I'll put them here anyway but I can always move them.

In the Start Graphing dialogue, I'd like to be able to define lasers and save them with a description so that doing a second or subsequent test on the same laser would be a matter of choosing it from a drop-down list.

Export and Import don't seem to be enabled menu items for me.

And would it be possible to Save the graph as a bitmap? Maybe even auto-appending a timestamp to the description to generate the default filename.

Also I noticed that the auto-ranging feature doesn't always make a sensible guess for the Y-axis maximum at the end of the test. For instance, I might set an expected max of 1,000mW and run the test, the laser peaks at maybe 700 and then the final graph has a Y max of 1,200. Instinctively I'd put that down to a rogue peak reading, but there never seems to be one. I've been too busy using the software to care about it

Oh and can we have a "Quick test" button on the main window which immediately starts a test run with a set of configurable defaults? 60 seconds, 40mW start threshold, 1200mW max, sort of thing.

And another thing.. how about complete auto-ranging, so that the Y max constantly adjusts to 120% (say) of the highest reading for the session?

If you could have all that sorted by ooh, 3 o'clock my time, that'd be fine ;-)