Laser Projector - Finished

EDIT: For the result, see here:
http://laserpointerforums.com/f47/laser-projector-building-phase-90283-3.html#post1327947

For the past weeks - what, 2 months already? - I've been playing around with a laser, set of galvo's and trying to get a small laser projector working. (See here. Thanks to everyone who's helped me so far! Even though it doesn't work perfectly yet (no proper mounting, incorrect control from HE laserscan ) I've learnt a lot. Now that I feel I have an idea of what components are needed / how stuff works, I've started planning a 'decent' laser projector. Below is the plan, you'd help me a lot by reading through and commenting on anything you feel is worth mentioning!

(Apologies for the long post in advance)

Goal
Have a self-built laser projector which is strong enough to be able to be used outside at night at a ‘larger’ projection area (e.g. side of house without windows) or sky during a foggy night, yet can be powered down to say 5% for safe indoor use & testing of patterns on the wall without having to wear safety goggles all the time.

Not intended for clubs , professional shows or whatsoever, just for myself to have fun with, experiment with programming shows, maybe try my hand at a laser harp, etc etc.

----------------------- Updated laser choices ---------------------------------
I've decided to not buy the RGB bricks because from what I've read their 'analog' modulation is actually PWM (is okay, but not for projectors) and they didn't respond well to modulation anyway.
The changes are as follows (also edited in above post): (All colors are links )

Three separate lasers, combined with these dichroics in these holders.

Blue laser
445/450nm, 600mW, $81 from newgazer, runs on 12VDC. 6mm beam size is pushing the max size of my mirrors, but I think I can live with it. <4mrad divergence seems a bit much, any experience?

Red laser
638nm, 200-300mW, $94 dollar at laserlands, 5mm beamspot, 1mrad divergence, 12VDC.

Green laser
532nm, $94 at laserlands, 3mm spot size, 1.5mrad divergence, 220VAC

----------------- End of updated laser choices -------------------

Galvo set & Galvo Drivers
Already got this set

DAC
Already got it, this one.

Signal processing
PCB (Printed at my Uni) for 5 correction amps (X & Y from soundcard --> -5V to +5V and R, G, B from soundcard --> 0V to +5V

The RGB-signals will be fed to the show-card that came with the galvos via the ILDA cable. The showcard has its own connectors for R, G and B. I assume that the RGB-signals can be simply plugged from these connectors into the RGB-driver connectors?

Alternative DAC/Signal Processing
If it turns out my current soundcard doesn't work properly with HE Laserscanner (it currently recognizes the card but seems to put all signals in one channel. I think. ), I might buy a correction amp. I know about Easylase, DrLava's thing, etc etc, but they all seem to be some years old. Does anyone happen to know which ones are still being sold?

Laser goggles
This one?
Seems to good to be true?

Estimated costs (Based on Ebay or €€€'s )
220 USD - Lasers
14 USD - Driver
28 USD - PCB
42 USD - PCB Components
42 USD - Alu baseplate
42 USD - Switches/Screws, etc
60 USD - Laser goggles
----------------------
~450 USD


So, yeah. Long post. If anyone has any comments, whether they be "Cool, good luck!" or "You screwed up" or "You're gonna screw up, try this instead", anything is welcome!

Re: Laser Projector - Planning phase

Time for an update. I'm back from holiday and have been looking for what lasers to buy for the full RGB projector. I've decided to not buy the RGB bricks because from what I've read their 'analog' modulation is actually PWM (is okay, but not for projectors) and they didn't respond well to modulation anyway.

The changes are as follows (also edited in above post): (All colors are links )

Three separate lasers, combined with these dichroics in these holders.

Blue laser
445/450nm, 600mW, $81 from newgazer, runs on 12VDC. 6mm beam size is pushing the max size of my mirrors, but I think I can live with it. <4mrad divergence seems a bit much, any experience?

Red laser
638nm, 200-300mW, $94 dollar at laserlands, 5mm beamspot, 1mrad divergence, 12VDC.

Green laser
532nm, $94 at laserlands, 3mm spot size, 1.5mrad divergence, 220VAC

I'd really appreciate it if someone could tell me something about the choice of lasers: Will they do what I expect them to do? Are there any obvious pitfalls I'm missing? I've found a great casing for everything, so I'd like to start buying soon

Re: Laser Projector - Planning phase

You're going to get a lot of fringing with the red laser, assuming it's multi-mode. The blue multi-mode laser won't be that bad, but it will fringe as well.

It would be better (in my opinion) with a single mode blue, and a single mode red. The poor beam quality is not worth the extra power with multi-mode diodes.

From personal experience my old 400mW projector was fine for outside use. Remember that 2x the power does not mean 2x the brightness

Re: Laser Projector - Planning phase

Thanks for the reply!

What makes you think/assume the red one is multimode? The mode mentioned in the datasheet is TE00. (But then again, the datasheet says 650nm, while the ad says 637/638nm... So it's probably not too accurate)
Same goes for the blue laser, where does it say that?
(Not calling you out, just wondering what to look for in ads)

Re: Laser Projector - Planning phase

Personal opinion -

go with single mode lasers, the beam specs will be much better
DTR has an awesome set made for this.

You will have a terrible issue with mismatched size beams and multimode lasers unless you use lots of optics and have someone who has done this adjust them.

I would guess the red is single mode

Blue and Green will very much overpower the red. IMHO. To compensate you will lose a chunk of your power on those two colors for proper balance.

Visit PL and ask one of the guys who does this every week. I've been planning for a couple years (taking it slow) and I've changed ideas on what to use a number of times.

check out this projector. Scanners were pricey but the rest is relatively cheap. No fringing and almost perfect colors
https://www.youtube.com/watch?v=_kwJydIxEus

Re: Laser Projector - Planning phase

Even though there's no real size reference, that looks tack sharp!

The DTR-set looks really great. I'll shoot him a message tomorrow to enquire about some possibilities. Based on ARG's 400mW-comment, I might be happy enough with some downsizing and go for the DTR-set. (Again, the 1W-wish was based on the internet, not experience )
I'll keep you all posted.


Oh, as for PL... Can I say I just have a better feeling here? I posted nearly the same question over there when I started with the projector (Simple Galvo set - Requirements & Possibilities?) and I've just gotten so much more help here, and the first impression does so much

Re: Laser Projector - Planning phase

Svenvbins said:

Thanks for the reply!

What makes you think/assume the red one is multimode? The mode mentioned in the datasheet is TE00. (But then again, the datasheet says 650nm, while the ad says 637/638nm... So it's probably not too accurate)
Same goes for the blue laser, where does it say that?
(Not calling you out, just wondering what to look for in ads)

Click to expand...

The red one I'm just taking a guess on it being multi-mode based on the price and the output power.

The blue one is definitely multi-mode as there are no 600mW single mode diodes for that cheap

The DTR single mode diode set is great. IIRC a couple people have made projectors using that set.

Re: Laser Projector - Planning phase

ARG said:

The DTR single mode diode set is great. IIRC a couple people have made projectors using that set.

Click to expand...

The one I linked to is definitely from the DTR set. It's Swamidog's personal one for setting up new shows he just built recently. Using DT-40W scanners and the DTR single mode diodes. It's about 400mw total power.

Re: Laser Projector - Planning phase

Diodes, heat sinks, drivers, glasses, and dichroics have all been ordered. Now, it's time to wait!

Re: Laser Projector - Building phase

Most of the stuff has been delivered, and I'm just waiting for the filter holders to drop in my post box.

Basically all I have to show right now are pictures of how it's going. The bottom level will be for lasers, drivers, galvo and filters. The flexmods haven't been attached yet, just for indication of where they'll be. I had to stack 3 metal layers to get the lasers at the same height as the mirrors. While taking the pictures I also realized I'll have to cut out a corner of those 3 layers, or the filter holder will block the beam...
The second level will hold PSU, correction amp and showcard.
And of course there's the soundcard DAC, using a 6-pin DIN cable (those are hard to come by ) to transfer the X, Y, R, G, B and ground from laptop / DAC to the projector.

Questions:
* Currently have the +-15V PSU that came with my galvo's. I'm trying to find a 9V 1A PSU for the diodes, because 15V on a red diode creates a lot of heat from what I understand. 9V is about as low as I can go while still taking care of all diodes. (max 7V for the green or blue diode (forgot ) + 1.5V for flexmod). Do you think this is a good approach, or can I just use the +-15V one?

* Will bolting the flexmods to the base plate (which has been sand-blasted to remove the paint) provide enough heatsinking for the diodes & flexmods? I'd think so, but it won't hurt to ask.

* I'm not sure what the showcard does. It has (among others) ILDA input, and (among others) outputs for galvo's (visible as 4 wires in top right of the close up) and laser modulation (2pin connectors bottom right). Wouldn't it be much more efficient to skip the whole card and just directly send the signals from the correction amp to the galvo- and laser drivers? Or does the showcard do something to the signals?

* Do you like it?

Re: Laser Projector - Building phase

Hi,

Since there's been some discussion about my projector, I thought I'd post some info about it to help other folks with their builds.

the little diode projector i built is using the following components:

1x RGB diode kit from DTR: https://sites.google.com/site/dtrlpf/home/diodes/rgb-diode-budle

3x Flexmod P3
1x 12v 5A PSU
DT40w's
Laserwave Dichro Set
4mm1's and mounts
2x first surface mirrors
1x dz ilda breakout board

the case i used was the one that platinum on photonlexicon was briefly selling (i hope he makes more). the case artwork is my own design.











i have not measured the power output. my guess is at white it's somewhere between 250-300mW. the beam specs and color modulation are pretty incredible and it's absolutely bright enough for living room use. i use mine for all my show programming and all the recent laser show videos i've been posting to youtube.

really, i think these are the perfect little projectors for home use. i can program on it for hours without getting eyestrain and it's quiet and reasonably safe power levels. i am considering doubling up on the blue and green diodes (using pbs cubes) to boost the power a little. the red diode is more powerful than the blue and green so i have to turn it down a bit for good color balance.

for these little diode projectors, i like to display a greyscale frame and adjust the flexmod bias until the low end color modulation and power levels are as close as i can make them and then apply 5v to the modulation input and adjust the full power levels until the white is as close as i can make it. this leaves very little to do in the way of palette training.

these are probably too low power to be effective beam projectors unless you like filling your house with haze/fog/smoke, but for graphics and abstracts they're fully awesome.

when doing show programming, i typically project on a 30x40" screen at ~15'

Re: Laser Projector - Building phase

Wow, that looks like a really clean build. Must be much nicer to work on than trying to find pieces of scrap metal
Last pieces actually came in today, so next week I'll try to finish my build - hopefully it's ready on friday so I can show my birthday guests what I've been spending my evenings on.

Re: Laser Projector - Building phase

Svenvbins said:

* I'm not sure what the showcard does. It has (among others) ILDA input, and (among others) outputs for galvo's (visible as 4 wires in top right of the close up) and laser modulation (2pin connectors bottom right). Wouldn't it be much more efficient to skip the whole card and just directly send the signals from the correction amp to the galvo- and laser drivers? Or does the showcard do something to the signals?

Click to expand...

You don't need the show card. In my projector I placed the DAC internally with just a USB and power cable connection. Most projectors have the DAC external to the projector and would then use something like a show card to connect the projector to DAC.

Need Help

I'm afraid I'm in need of some help. Since my birthday 'party'/evening is next friday (turned 23 last weekend!) and I wanted to have a somewhat working projector to show to my friends, I could even say it's slightly urgent So any help is greatly appreciated!

I planned to install the Flexmods and lasers today, and finish final connections & alignment tomorrow / thursday. However, I didn't even get to install 1 driver.

Although I think I connected everything correctly, the Flexmod shows a red 'error LED' whenever I power it. My connections are as follows:
(Following the step-by-step manual from here

Mod+ ----> Shorted to ground in order to set bias current.
Gnd ----> Connected to the "-" wire from my 12V PSU.
V+ ----> Connectd to the "+" wire from my 12V PSU

Out+ ----> Directly linked to the multimeter for current measurement.
Out- ----> Directly linked to the multimeter for current measurement.

Interlock --> Linked to the V+ via a mechanical switch.

The PSU has only two wires, + and -, so I'm guessing - should suffice for ground for now. However, as I said, I only get the Fault Led, and no current to be measured.

Who can help me out? Thanks a lot in advance!

Re: Laser Projector - Building phase

That should work. Do they all behave like that?

Re: Laser Projector - Building phase

Cyparagon said:

That should work. Do they all behave like that?

Click to expand...

Thanks for a fast reply
I've only tried one so far because it took me longer than expected to solder the wires. (Wider holes, soldering stuff sticking to iron instead of holes/wires, etc). And at some point around 22:30, you just wanna go home.

First chance to try another one is either somewhere tomorrow late night, or else the day after tomorrow. I just hope I didn't break the driver with heat, I tried to limit the soldering but you never know...

Just checking if I indeed DON'T need a dummy load. In most driver stuff I read you needed one, but this manual doesn't mention it. Am I correct here?