1W+ 445nm Viasho Mod (17 Pics)

Hi All,

Well, it's been a long time since I posted a build and we can't have that now can we!

This was a quality 100mW 532nm Viasho laser at some point but unfortunately it seems all the photons ran out and the output had become... Let's say disappointing to be polite.

I was set on the search for one of these by commission as someone I know wanted a 1,200 - 1,300mW output, 445nm laser in this specific host as he has others like it. I found one through a couple of contacts, (one a member here, thanks Andy!), and took way too long getting around to looking at it. Sure, the old module came out easy enough, but there were some tricky aspects to the build.

The basic run down of parts is nothing surprising. The host runs from a 18650 battery so it's pretty standard stuff:

A140 445nm diode
Aixiz to mount it
3 element AR coated lens
Flexdrive V5 at max, (around the 1.2A mark)

Then came the harder bits...

First came machining the heatsink. Fitting as close to the interior as possible and mating with the main body this was a relatively simple piece of turning and I used my, "Driver Manifold", to heatsink the driver and fix it inside the main heatsink. The Aixiz module was fitted into the interference fit hole with heatsink plaster.

Here are a few pics of that -

From the back with the driver manifold in place and back plate removed



Back plate in place


I used a rubber O-ring so the host pinches the base of the heatsink to the body for the case positive connections. This allows the host to be nipped up tight, closing all gaps, without ever compromising that joint through heat expansion of the internals.

Rubber O-ring



Then to turn up a focus ring. This needed to be a bit special as the host deserved it. I wanted to make it a captive focus ring that was never in danger of just being unscrewed and coming away from the laser. It just turns and the outside dimensions of the laser never change as the lens moves inside the ring. With this build, the focus ring was matched to fit the profile of the existing chamfers and keep the lines of the original. The aperture in the laser also had to be opened up, losing the shutter mechanism, to allow the focus ring through. It's this front cap that holds the focus ring flush and the flange prevents the focus ring escaping.

Here's a pic before installation



So now came the hardest part of all. The electricals! I had no idea just how the original laser was regulated. The parts had no numbers on them; I couldn't trace the tracks on the double sided board, (the one that was initially visible!); there had been some modification to the board at some point; the push button switch alone had 6 poles!; etc... I was scratching my head for some time on this one.


The main board in place with negative spring contact, (532nm case positive remember. The customer asked to keep this configuration so there could not be a mix up with his other large green lasers)


Removed, showing the underside...


... and push button contacts behind



Not only could I not tell what regulation parts there were but the main board also had connections for the LED that showed green when the laser was activated, from the tailcap key switch, and red when the push button was depressed and the laser was emitting 532nm photons.

All this functionality I wanted to keep. (The customer actually wasn't too fussed about this but I wasn't going to be beaten!). I decided the only way to go was to remove the electrics completely and draw out what I could. For some reason, that I found out later, the wiring on these is really complicated. Not just a contact from the battery and one from the case. Oh no, that'd be far too easy!

The reason the wiring is so complicated? There is a hidden board and large ballast resistor, (never did find out just what that did!), tucked away in the barrel. This seems to be why the battery is off centre in these hosts. I tried several different ways to connect this hidden board after realising it was most likely the LED driver board and, after removing one resistor at a time from the main board and slowly gaining output we hit full power when left with no resistors at all! This was expected as the module containing the driver, etc, should now have been doing all the regulation just connected straight to the battery, but I didn't want to risk blowing the LED after all the work...


Poxy little board, (all heat-shrinked up!), that meant a fishing trip each time I needed to connect it!



I wasn't fully able to measure output as I'm still using my LB1, (tops out when reading 1,050mW), but experience tells me that when the meter stops reading, and the numbers are climbing that fast, we're hitting about 1,300mW!


Here are the exploded pics -










Front(ish) view


Red on...


Green on...


GO!!!



There we have it. A high output 445nm Viasho! I'm sorry I didn't take more photos of the construction as it would have been more informative. I was concentrating far too much on the problems at hand though but these ones at least show everything after work was completed. It turned out okay in the end.

The customer is very happy with it, and I hope you like it too.

Thanks for reading.


M

Spectacular work! I really like the way you finished off the front with that bevel, if i were your customer i would be more than pleased

It has been a while. Good to see you back at it.

That custom module is awesome, the focus adapter really make it stand out and you kept the original circuitry intact. Great work all the way around.:beer:

Many thanks, it is always a pleasure for work to be appreciated.

The circuitry was a pain but the focus ring was the USP on this one though. Once upon a time, I dropped an early build from a low height and it landed right on the focus ring. As I was using the standard Aixiz plastic lens, it buckled and got wedged in the threads, (I think I was just about up to the PHR builds at the time!). I had to properly mangle it with some pliers to unscrew it. Ever since, I've always seen the focus ring as the weak point. Even if you are using the metal lens holders and have a turned focus ring, press fit, glued, or whatever, the lens threads are vulnerable and the shock is transmitted directly to the module and diode. This one separates the two systems a little as no force can be exerted on the threads in that instance. It required some CNC milling but the outcome was definitely worth it.

Previously the advice would have been, "Don't drop your laser!". All very good but accidents happen. I would be confident to drop this one on the front and not damage the threading at least. It could break the diode but...

Despite the protective element, it's just cool to focus the laser in a similar way to using a camera!

M