Jumping into the self-build fray

[frostypaw]

Thanks for the reply - great set of questions, I wondered about grounding but thought I had it - I'll try and answer:

Red channel behaves perfectly, set up first time no problems. Blue and green have the same problem, though blue currently dead

When I go straight from a lab PSU I can't get the bias down low enough for the PL520 to stop lasing - it's always pretty bright at around the 60mA minimum. Once the gain/upper limit is set the steps as I ramp up are lovely and instant, the steps down are instant until the last one to the anti-glow threshold of 0.24v which fades out over a second. Jumping straight to 0v seems instantly off.

AC grounds of all supplies are together and that presumably to the baseplate via their cases.

I have three supplies - one 12v for diodes/drivers and a pair of 24v's in a symmetrical arrangement with the common ground linked to pin 25 as per Eyemagic's instructions.

The scanners are EMS4000's in their normal case and mount. Considering they don't generate any heat so speak of should I have those entirely isolated? Should the PSU's be isolated?

ps. your lovely beam profiles inspired doing this *bow*

[frostypaw]

OK after a night out ended more abruptly than expected I have numbers and facts.

Scanners already insulated (thx Eyemagic)
Whole scanner/ilda board DC ground was connected to one point, whole circuit isolated - pin25 connected to common ground.
Whole diode side one ground, whole circuit isolated.

Connected those two grounds solidly, but that made no difference.

Then noted the currents drawn by the green diode at various levels over threshold and it is definitely weird:-
<0.24v - 0
0.24 - 54
0.26 - 57
0.28 - 65.5
0.30 - 60.5
0.32 - 61.5
0.34 - 62
etc smooth-as from there but the highlighted one....

[frostypaw]

Might not be relevant now. Tried going through their checks again and as I moved the board and the super-hefty wire flexed the diode pins again the anode on the PL520 broke off completely. Gutted, and wondering that's what had killed the blue.

Get to try again with a new diode I guess, only bugger being had already ordered the replacement blue.

Putting it all to one side until the nice wire turns up I think, and might return all these drivers as they've been a nightmare when most folk seem to have no problems setting modulation up. Flexmod ahoy I think?

[dkumpula]

I've broken a couple diode leads over the years. Its rough. You want to use flexible silicon wiring or non-hefty copper/alum wiring. The heat shrink insulation should help keep the diode leads from flexing as well.

Regarding the driver, you want beam suppression with the low power diodes, so I would avoid Flexmods. Beam suppression Flexmods are sold only by Innolasers and require some challenging soldering. I have had a variety of problems with the beam suppression Flexmods as well - beam suppression not working, erratic output, stuck gain pots, and total failure. One of the failures was a bad solder joint (my fault), but the others have not been explained. I have purchased about a dozen of these and have over 50% failure rate. I have not had any issues with the non-beam suppression models.

Alternatively, I would recommend this driver sold by PL member BBE. They are true analog output, have reliable beam suppression, optional overheat protection, optional interlock, bias setting, easy current measurement, status LEDs, etc. I have several of these and have nothing but good things to say about them.

Another good alternative is PL member Dave's driver available on Lasershowparts.com. They have most of the same features as BBE's. I have at least a few and find them reliable and easy to work with.

-David

[frostypaw]

Cheers fella, recovering from the grump now - it's all a lot rosier than my best mate's helicopter crashes really. Have now removed all their wiring, rewired and tested the red diode which is still ok and the pins are still firmly attached. Had little more than a "works for everyone else, if our wires broke anything it's your fault" from Lasertack. Sure soldering is my part of the job but if you provide wiring to connect to a laser diode it's nice it if it's actually suitable for connecting to laser diodes. On their way back to them now.

Gonna leave it all well alone until the slinky DTR-recommended wire comes.

Excellent advice on the flexmod - reading their manual now I see that adding suppression disables some other features too. I'd been eyeing BBE's drivers as it turns out, may have to make that happen. Real international business this isn't it! Thanks

[Galvonaut]

Hey Frostypaw. Looking forward to following your build. I am just re-starting my single mode build having a pause thanks to a rather demanding project - so shopping for parts as well.

Keith

[frostypaw]

Hope y'all have had a merry christmas - shame the boxing day sales never make it down into our niche eh! or maybe that's a good thing.

Hey Keith, I see you've been around a while so doubt there's much new I could help with outside of specifics, but I'll share what I can! DTR gets one of my unusual total recommendations but you probably know that. The new drivers seem promising, not found a bad word about them. As a near-local it'd be fascinating if you take a different method to be able to compare side by side, photos rarely compare to real life and with so many variables it's all a bit mind boggling for me still.

[Galvonaut]

I've been around a while but still new to this malarkey! I've built a few bits and bobs but this will be my first full colour attempt - so plenty to learn!

I have the DTR single mode bundle x2 which I'm going to PBS cube together - or at least attempt to! DKumpula suggested an upgrade to the greens now that there is a higher power single mode available - so I'll be ordering some of those shortly.

We are pretty local - so might be good to compare builds and help each other when we get stuck or need inspiration!

[frostypaw]

It's great fun you'll love it - the aligning process was full of 'coo' and 'aaah' and 'oooh!' and that first rainbow was like a new dawn :lol: but really. I wonder how many lasers you have to build before you get bored with it, research so far says more than one.

The green upgrade probably wouldn't help with your RGB balance - the relative brightness is wildly disparate.

Using the relative brightness calc: http://lsrtools.1apps.com/relativebr...nm1=520&mw1=80
80mW of 520nm green matches to (as dots for graphics):
297mW of 638nm
1339mW of 445nm
or for beams:
684mW of 638
709mW of 445nm

So the 'correct' white ratio is near 450:80:900mW for 638:520:445nm whitelight - kinda surprised me. This is why I'm happy to have the green right at the back of my optics, I can lose a shedload before I ruin my white balance even if every mW of red/blue gets through unscathed.

Though if you're wanting to whack huge pure green beams out then it's well worthwhile as it will be a helluva lot brighter! I'll be very interested to see what double of each looks like though as that's a logical next step

I saw your heatsinking question too - once the heat sources (mosfets/amps/laser diodes/etc) were fixed to the baseplate nothing got past skin-warm, even on it's night of very heavy use when everything almost worked!

[KANG]

Glad to see the single mode builds Currently upgrading mine w/ new diodes/mounts for fun plus the tight beams are just awe.