Laser Projector - Finished

[Svenvbins]

Re: Laser Projector - Building phase

And that, my friends, is how you go from "That laser looks cool!" to "How electronics work"
But it's interesting - and essential, so I don't care.

Your first device was supposedly rated for 1A as well, and it dropped below its rated voltage, which suggests you were operating it above 1A. What current are you expecting to run your three diodes at?

I thought dropping below the rated voltage was a result of being a crappy unregulated adapter, not operating above 1A?

I'm planning to drive at 165mA+200mA+165mA=530mA for starters, maybe increasing it a bit later to overdrive the lasers to ~ 200mA+250mA+250mA=700mA.
Assuming the flexdrives themselves use a negligible current, 1A, but especially the 'new' 1.25A should be enough.

Just came back from the lab, both Flexmod & diode are dead.

Hooked the diode up to a controllable/regulated power source. Current at zero, voltage at 12V, slowly upping the current. Could up the current all the way to the max of the PSU (which should be 2A, and yes that would DEFINITELY kill the diode), but no-where along that track did I get even a little bit of light.
As for the Flexmod, disconnecting all wires and connecting a 9V battery to Gnd & V+ resulted in 2secs nothing, after which a fain high-pitched noise could be heard. During the 2 secs, the current was about 300mA, during the pitch (which lasted until I disconnected the battery) the current was ~150mA.

So, I'll be buying a new diode & flexmod, and triple checking the settings on the other diodes & drivers before I continue.

 

[The Lightning Stalker]

Re: Laser Projector - Building phase

What were you using as a test load on the
FlexMod?

9V batteries are pretty weak.

The only things that will kill a driver, that I'm
aware of, are overheating, overvoltage, and
reverse voltage.

 

[Svenvbins]

Re: Laser Projector - Building phase

Test load - None. In that case, the red LED should've activated ("Open load loop"), but that didn't happen. (Interlock was open too, so should be double reason for red LED).
(Therefore, I think the fact that I used a 9V battery shouldn't be too important)

Over heating - Probably not, have felt the transistor a couple of times when it still worked but didn't get hot. While testing after it broke, some parts on the PCB get warm, but might be normal operation or result of breaking.
Overvoltage - Probably not. Adapter was not regulated, but graded at 9V, giving 12V without load, and Flexmod can take 24V.
Reverse voltage - Maybe I caused some kind of reverse voltage while trying to apply the pins for the multimeter. That *was* the point where it stopped working all together. (Was fidgeting near the interlock-connect)

(Probably buying a new one, but maybe someone with a Flexmod lying around can check the current when connecting nothing but a 9V battery? See if it's similar or completely different to mine. 150-300mA without load seems to be quite a lot to me.)

 

[Svenvbins]

Re: Laser Projector - Building phase

Nope, not dead yet! New Flexmod has arrived, just waiting for the new greenie now. Also considering buying some aluminium sheets (thick), since lasers need to be lifted 8mm to be at the same height as the galvo's, and the set of lasers+galvos need to be another 4mm higher to prevent any clipping on the dichroics.

Found some glycerin today as well, so I just have to share some pics of the current blue+red state

 

[Svenvbins]

Laser Projector - Done!

About 4.5 months ago I came to LaserPointerForums as a guy who loved the pure color of lasers and just had some fun with mirrors glued to some speakers. I considered building an own projector, and with massive help from many people here I can now proudly say I'm (pretty much ) done! I've advanced so far that I can call it finished.

It's a ~220mW projector, with about 130mW of red, 80mW of blue and ~15mW of green. (Why so little green? Read on! The movies have red and blue adjusted for the green, btw) Back when I started I had a total power of ~1000mW in mind, and while I'm sure that would've been even cooler, I keep being surprised how bright these lasers already are. I promised that when I would finish the project, I'd write a guide on what I did, and that guide is still coming, but for now, pics & movies!

https://www.youtube.com/watch?v=qCDrOHpzXGE&feature=youtu.be
(In the end I'm adjusting the intensity curves for blue & red, that's the clicking you hear. And my chair squeaks )


https://www.youtube.com/watch?v=CriPRbnzZRI&feature=youtu.be
Didn't feel like heating up the wok, carry it to my room and evaporate some glycerin, so - my room smells like deodorant now!

https://www.youtube.com/watch?v=QsqrMW48tAk
And one more video, the best one so far

Short summary of most important components:
* 20K galvo's from Ebay.
* DTR's RGB diode set
* 3 Flexmods
* Dichro's & mirror stands from Ebay.
* Goggles from ebay (tested to sufficient quality)
* Casing from the scrapbox at my uni.

The top slides off, the inner top level can slide forward & backward for somewhat better access to stuff below. Top level contains PSU, correction amps for XYRGB and showcard, bottom level contains all drivers, lasers, galvos and dichro's. Backside has 3 switches for red, green & blue. All in all it has probably cost me more than a projector from China, but the experience of building it myself and understanding how it actually works is worth a lot too!

As I said, it's "Pretty much" finished. That means that there are still things to improve which I'll keep fiddling with, but if anyone asks I can say "I have a full RGB laser projector" without lying. What's there still to do?

1. Replace Dichro
   The dichro that's supposed to pass green and red and reflect blue has its cut-off wavelength just below 532nm. The green diode is a 520 one. Completely missed that when ordering dichro's, so now I get about 15mW of green on the galvos and 30mW of green is lost because it's reflected. Anyone who has a nice source for a pass >510nm or so? I'm guessing they're more expensive...
2. Add front & back cover
   Because that would just look much better
3. Fix crosstalk
   Ah. Aaaah. Hehe. Mhm.
   When I modulate the green power, the SIZE of the show changes. Setting green to TTL gives a steady image, setting it to analogue sometimes results in vibrating images. I think it also affects the power getting to the blue laser, as in some cases the blanked lines show up as faint blue, especially when green is involved somewhere. (See 2nd pattern in first video. Supposed to be four constant-size squares with color pattern going around - the blue should NOT disappear) I'm guessing this is because all Flexmods are attached to an aluminum plate (heatsink) which connects to the frame (heatsink for galvo drivers) and apparently the transistors aren't signal-less where they connect to the sink. Not sure how I'll fix that yet, but we'll see

ARG, Bionic Badger, Benm, Ice Cruncher, Swamidog, Cyparagon, Lightning Stalker and anyone else I forgot, thank you so much for your effort & patience!