Need some help! My first RGB projector project (expecting approx. 2W system)

[taggalucci]

Hi all,

***UPDATED***
This post has been updated to reflect the current specifications...

The current 3W build includes:

• 1 x Laser Century ~450mW 473nm Laser, Lab-style PSU & 10kHz analogue modulation
• 1 x CNI ~550mW 532nm Laser, OEM PSU & 10kHz analogue modulation
• 1 x CNI ~1000mW 635nm Laser, OEM PSU & 10kHz analogue modulation
• 1 x home made ~1000mW 445nm Laser, Casio A140 Diode with Dr Lava's Flexmod N2 driver with analogue modulation
• 2 x Cambridge Technology 6800HP scanners
• 2 x Cambridge Technology CB6580 Rev. D scanner amps
• 2 x 24v Meanwell SMPS wired to provide dual rail +/-/ground for scanners
• 1 x 5v Meanwell SMPS for both CNI and home made lasers
• 1 x 12v home made regulated linear PSU for a case fan and home made 445nm laser
• 4 or 5 x 240v AC case fans
• 2 x 12v fans, one case and one for home made 445nm laser
• 1 x SafeGuard Lite PCB
• 1 x Stanwax ILDA Interface Board
• 1 x home made AC power distribution
• 1 x home made remote with E-Stop, Run, shutter override and ready/emission indicator
• 1 x home made aluminium enclosure

. .

. .

. .

***ORIGINAL POST***
I intend to build an RGB projector with the following components, most of which I've received, and the remainder on order:

• 1 x Laser Century >450mW 473nm Laser, Lab-style PSU & 10kHz analogue modulation
• 1 x CNI >450mW 532nm Laser, OEM PSU & 10kHz analogue modulation
• 1 x CNI >900mW 635nm Laser, OEM PSU & 10kHz analogue modulation
• 2 x Adjustable optical mounts with colour combining dichros in the order Red->add Green->add Blue
• 2 x Adjustable optical mounts with first surface mirrors
• 2 x Cambridge Technology 6800HP scanners
• 2 x Cambridge Technology CB6580 Rev. D scanner amps
• 1 x 80x80 AR window
• 1 x SafeGuard Lite PCB
• 1 x 12mm or 16mm thick aluminium plate

I am considering a two shelf design with the lasers and optics on the lower shelf and the PSUs and scanner amps above. I will probably have a couple of fans on the upper shelf blowing into the unit with vents opposite.

I am toying with the idea of an airtight, dust free optical area. I have no idea how to go about this as I could not see much on the forum relating to this.

I am also mindful of meeting Australian guidelines on construction of this unit so that I can comfortably use this in a public venue. I am aware that there are design and safety guidelines set out in AS/NZS 2211.1 (although I do not yet have a copy of this - it's a rather expensive document containing much more information than would be relevant). I'm expecting an interlock, shutter, keyed remote emergency-stop, keyed switch on the unit and appropriate labelling. I'm not sure if I've missed anything. Any of your advice and experience in this area would be appreciated. The Australian standards are copied directly from the IEC 60825 documents. So international standards advice would be applicable and welcomed

I have a friend who's a sheet metal fabricator, so he's got access to various aluminium bits and pieces and can probably build the outer case.

Here are my current open queries:

• I have access to 16mm aluminium for the base plate, is this overkill? I also have access to 12mm plate.
• Does anyone have any experience with creating sealed optical areas? I would be interested to hear about the pros and cons and what materials would be recommended to provide the seal and what constructions process people may have used for this.
• If a shutter was required for safety, as opposed to the alternative of killing power to the lasers, what sort of material should be considered a good beam block for 2W? What would be the most effective and inexpensive actuator for this shutter?
• How would an interlock connect to the system?
• How would a keyed switch on the unit connect to the system?
• How would a remote emergency stop button be connected to the system?
• How will I connect the scanner amps to the SafeGuard Lite PCB?
• Have I covered all of the safety requirements I would need to conform with to meet the guidelines/standards?

I plan to provide photos during design and construction.

I have also discussed with the promoter of a dance event in Melbourne, the possibility of testing the unit out and have agreed a date in April.

Looking forward to hearing your views

Cheers,
Tony

[danielbriggs]

I can't answer all your questions, but I'll have a stab at a few.

Hi all,

I'm new here, so please be gentle!

Welcome aboard Tony!

I am considering a two shelf design with the lasers and optics on the lower shelf and the PSUs and scanner amps above. I will probably have a couple of fans on the upper shelf blowing into the unit with vents opposite.

Just make sure you have a positive case fan pressure, that should eliminate the build up of most dust.

I am toying with the idea of an airtight, dust free optical area. I have no idea how to go about this as I could not see much on the forum relating to this.

I assume everyone strives for this. Now I'm not talking hermetically sealed cases But +ve case fans and an output window seem to work well.

I have a friend who's a sheet metal fabricator, so he's got access to various aluminium bits and pieces and can probably build the outer case.

Nice one. But don't get the aluminium done on the guillotine. (12-16mm is a bit ambitious for a guillotine anyway...). Invokes edge stresses and can lead to slight thermal warping. 12mm seems a really good choice IMO.

I have access to 16mm aluminium for the base plate, is this overkill? I also have access to 12mm plate.

Yes. I use 12mm on mine and that is loads. I can't think of any large benefit of the extra 4mm. Weight is a killer!
Some people use 6mm - but it warps and goes out of alignment if the plate temp increases.

Does anyone have any experience with creating sealed optical areas? I would be interested to hear about the pros and cons and what materials would be recommended to provide the seal and what constructions process people may have used for this.

Not me to that extent. See above...
One thing to remember: You WILL have to re-align at some point... every once in a while.

If a shutter was required for safety, as opposed to the alternative of killing power to the lasers, what sort of material should be considered a good beam block for 2W? What would be the most effective and inexpensive actuator for this shutter?

Black anodised aluminium? Not glued on though!

I plan to provide photos during design and construction.

Nice one! We like photos!

It sounds like you are going to have a REALLY nice setup there when all is said and done
Quick question: Have you bought the 635nm yet? If not, you may want to consider 640nm setup for better beam spec.

Hope that helps,
Dan

[buffo]

I'm new here

Hi Tony, welcome to PhotonLexicon! Sounds like a nice projector you've got spec'd out there. You are definitely spending a lot of money on it! Is this your first attempt? (Reason I ask is that this is a very big step if it's your first...)

Also, you didn't mention what controller you plan to use, or what the primary use of the projector will be. (Fun / hobby use or commercial.) You alluded to possibly using it in a club a few times, but will that be it's primary use? (If so, then the idea of sealed optics makes a lot more sense.)

I am toying with the idea of an airtight, dust free optical area. I have no idea how to go about this as I could not see much on the forum relating to this.

You can enclose the optical path area with plexiglass (acrylic) if you want. Or you can use sheet metal to enclose it. All you need to do is form it around the apertures of the lasers and attach it to the baseplate and the roof of the projector. It doesn't have to be perfectly air-tight either. Any enclosure, even one with gaps where the beams enter the enclosure from the lasers (that is, lasers outside the enclosure), will be better than nothing at all.

Make sure you can still get at the mounts to adjust alignment, and be sure you still have access to the optics for cleaning.

I am aware that there are design and safety guidelines set out in AS/NZS 2211.1 (although I do not yet have a copy of this - it's a rather expensive document containing much more information than would be relevant).

Ahem. I believe a copy of this document was uploaded to the FTP server a while back. Look around, it might still be there.

I have a friend who's a sheet metal fabricator, so he's got access to various aluminium bits and pieces and can probably build the outer case.

A handy friend to have! Stay on his good side... He can indeed help you fabricate the outer case, and can probably help you with the enclosure around the optics as well.

I have access to 16mm aluminium for the base plate, is this overkill? I also have access to 12mm plate.

How big is your baseplate going to be, and how will it be supported? 12 mm plate should be sufficient for an unsupported run of around 45 cm or so. (That is, supported only at the edges.) Any more than that and you might want to step up to the thicker plate. (Or you could just add some support underneath.)

As a general rule, thicker baseplates are better, but they do add weight to the projector. I'm only running a 6.5 mm thick baseplate in my projector (dimensions are 10cm x 35 cm), but I have it supported all along the long length by two thick beams.

Does anyone have any experience with creating sealed optical areas?

I did not do this on my projector, because I wanted easy access to the optics for adjustment and future modification. And I haven't needed to clean my optics yet. However, my projector is only used for hobbyist shows in my living room, so it probably sees less than 20 hours of use per month. A projector in a nightclub will see a lot more use (and more smoke / dust / fog juice residue).

For the record, I have not had an aperture window for the past year, and even so, dust has not been a problem. But the air in my home is not as dirty as that found in a nightclub, either...

what sort of material should be considered a good beam block for 2W?

Black anodized aluminum or steel (painted with black high temp paint) are recommended. Don't use anything reflective (such as unpainted steel) on a beam block. One thing you can do is mount a small mirror on the shutter arm at an angle to deflect the beam into a beam dump. This can be metal (as above) or ceramic, pumice or other volcanic rock. Just don't let the beam get reflected back towards the lasers. (This can kill a direct-injection diode.)

What would be the most effective and inexpensive actuator for this shutter?

Most effective: GM-20 actuator or clone. Least expensive: spring-return rotary solenoid. (This will be loud though.)

How would an interlock connect to the system? How would a keyed switch on the unit connect to the system? How would a remote emergency stop button be connected to the system?

Have a look at this schematic for one solution to all three questions. It's how my projector is wired. (Click on the image on that page for a larger version.)

How will I connect the scanner amps to the SafeGuard Lite PCB?

You'll need to check with someone who actually has one installed. I've never used one. There should be a feedback output on the scanner amps, but I don't know enough about the Cambridge amps to tell you where it is.

Have I covered all of the safety requirements I would need to conform with to meet the guidelines/standards?

It sounds like it. Remember: shutter, interlock, emission indicator, turn-on delay, emergency kill switch, key switch, and labels... Those are the basics, at least over here in the US. Of course, we still need to file a laser product report and apply for a variance before we can use our projectors commercially. Not sure about the laws in Australia though. Might want to check with some of our Aussie members for more details.

the possibility of testing the unit out and have agreed a date in April.

That's not much time to do all this! Hope you've got a lot of free time to spend working on the project... Looking forward to hearing about your progress!

Adam

[taggalucci]

Thanks Dan and Adam, and to Steve for his help on answering my CB6580 scanner amp query here...

http://www.photonlexicon.com/forums/...-amps?p=135694

When I get a moment later, I'll have a good look through all your advice, answer your queries and perhaps get a couple of photos up of what I have so far.

Cheers,
Tony

[badger1666]

hi you want to keep away from the 635 it has a very fat beam on the cni and most of it will miss your scanner mirrors 640nm is the way to go you wont regret it as anyone on here will tell you
if you have got it already send it back

[dave]

If your intending on doing public shows, a saftey board is essential, as is public liability insurance.. Bad idea doing any public shows without either..

[blowfly]

Ahem. I believe a copy of this document was uploaded to the FTP server a while back. Look around, it might still be there.Adam

Was poking around on the FTP server looks for that document but couldn't find it. I might have missed it though.

Mike

[taggalucci]

The lasers have literally just been delivered According to the included testing reports:

>450mW 473nm is producing 598mW
>450mW 532nm is producing 544mW
>900mW 635nm is producing 976mW


Dan and Badger1666,

Yes, my choice is red was pained over. I looked into a few options when I was pricing up the components and settled on the 635nm 900mW from CNI. Now I did discuss this with a local laser display specialist and was advised about the larger beam profile and the potential for larger galvo mirrors. I was advised not to buy a 671nm which I had considered (and would probably have needed a 2W, from what I understand)!

640nm was never discussed and, from what I can see, does not exist as a single unit in the power range I'm working with. I would be surprised if I were able to achieve the same reflected power (factoring in the loss from the edges of the beam not hitting the galvo mirrors) by combining multiple 640nm lasers for a similar price (factoring in expected lifetimes, build quality etc.). Cost has been a major factor, so there was always going to be a compromise. As with most decisions, I hope that I have made the best one!

For the 635nm laser, CNI offered me two beam profile options:

~5*9mm diameter <2.8mrad divergence
~4*6mm diameter <4mrad divergence

I chose the 2nd, i.e. the ~4*6mm, and hopefully that was the better choice to make despite the increased divergence.

I am intrigued about the possibilities of using optics to improve the beam profile. I’ve read suggestions like using a “reverse telescope” can do this. I understand that the energy of the beam is focussed in the centre of the beam so I also wonder if using an iris to shape the beam would work.

I welcome discussion on these points!

Cheers,
Tony

[danielbriggs]

I am intrigued about the possibilities of using optics to improve the beam profile. I’ve read suggestions like using a “reverse telescope” can do this. I understand that the energy of the beam is focussed in the centre of the beam so I also wonder if using an iris to shape the beam would work.

Cheers,
Tony

I think you'll find yourself out of luck unfortunately.
If you telescope the beam down, say by a factor of two for example, then the divergence will increase 2x.
"You can't get something for nothing." Swings and roundabouts... one goes up, one goes down.
However don't let me stop you - all credit to you if you find some way of doing it successfully.


Honestly... I would leave it as it. You're gonna get a shed load of power, the only downside is a bit of fringing on some of the beams. But see how it goes before you change anything major. (The reason I upgraded my homebuilt 660nm's to 640nm's was the fringing, but everyone has different opinions... ) BTW: You need about 1.7x less power of 640nm to match the brightness of 650/660nm. However with the right amount of tweaking you can get get a screaming white balance, and some lovely colours from nearly any set, there is no right answer...

I can't see this being a problem, but if you are really stuck and are loosing a serious amount through the galvo's. (I've not tried this BTW) but you could look at slightly focusing the 'white' beam, just before it hits the galvo's to a smaller spot size, then after the galvo's re-focus the beam with another lens placed after it's bounced off both mirrors. I don't know if this will work well in practise, just an idea off the top of my head.

All the best,
Dan

P.S. What hardware+software are you going to use to drive it?

[taggalucci]

Hi Adam,

Hi Tony, welcome to PhotonLexicon!

Thanks! I'm feeling the love And thanks for all the useful information you've provided.

Is this your first attempt? (Reason I ask is that this is a very big step if it's your first...)

My first projector is a cute little 60mW 532nm which has been through 2 rebuilds. It has an unfortunate history which I may share with this forum some time, if time permits. I have just taken the Cambridge scanners out of this and replaced them with new DT-30 scanners. I may post some pictures of this little projector, though it's not that interesting.

Prior to that, my experience with lasers began when working in a club in Zimbabwe believe it or not! When I lived there, I operated a 4W water-cooled Russian-made argon ion. This had a set of GM scanners and some UK-made rack mounted controller. It was this experience that got me hooked, and why I've always wanted to build a bigger unit.

Also, you didn't mention what controller you plan to use

I have a Medialas Mamba Black system. I've considered looking at the FB3 with Quickshow, but there's no desperate hurry on moving to this. I'm also interested in looking at the version 2.0 of Mamba. So a feature comparison of the two would be cool.

I also have a Chamtech PM20 that I'm fighting with. Since buying it over 5 years ago, I've never been able to get the bloody thing to load images correctly from PC over RS232. The manuals are full of errors and omissions and it took me ages to work out that the digitiser pad and serial port sockets were incorrectly labelled! At this time, I had also lost contact with Chamtech who were not returning emails, though I've recently found a different and working email address for them. So I plan to resume resolving this! This will probably stay with the little greenie.

or what the primary use of the projector will be. (Fun / hobby use or commercial.) You alluded to possibly using it in a club a few times, but will that be it's primary use?

I run a software design consultancy and that takes up most of my time. Lasers, lights and sound have been relegated to the weekend. Of course if someone were to need this projector for a gig, I would want it to be in a fit and safe state to be used for this. I will run it in a club in April as a favour to a friend, and as a means to check it out in that environment.

How big is your baseplate going to be, and how will it be supported?

Now that all the components have arrived, I will plan the layout and then establish the size. My intent would be for this to be as small as possible. The double shelf design looks great as a means of reducing the footprint. I will share my thoughts with this forum as I progress.

Have a look at this schematic for one solution to all three questions.

Sorry, I couldn't see that attached. Can you attach this again?


Cheers,
Tony