First Scanner (RGY)

Ok i received all the basic items to start my RGY project.
I have a couple of questions about "pratical things".
I have a 650nm 300mW and a 532nm 300mW modules with analog blanking, a passing red reflecting green dichro, scanpro 20k galvos set, fb3 controller.
Now i will need to get an alluminium plate to set everithing, i think 1cm thickness is good but i dont know how large... any idea?
I'm planning to get enough space to add a blue module and make a RGB scanner in future.
Is easy to make holes in alluminium with a vertical drill?

And i have another question about my red module.
The beam is kinda thick (and slightly point towards bottom but i think theres no real problem cause i can collimate it using a mirror.), i will gladly reduce its diameter to make it pass easily inside the dichro mirror.
Is there a way to obtain a more concentrate beam?
The beam become more flat after some metres ( i think it's called astigmatism), can be a problem?

I dont have other questions for now :D

Thanks

plate should be 1/4" or better and around 12"x12"

300mw green is overkill for mixing with 300mw red (tho analog modulation can take care of that), it should be a 3 to 1 ratio of red to green

sounds like you need to adjust the lens on the red. you should be able to focus it to where you need it.

My plate is 13"x13" and I can barely squeeze all of my RGB components on it. If I did it again I would probably use a double layer approach and mount all of my optics stuff on a small thick plate and all of the power supplies and electronics on something thin and light weight. There is no reason to mount them on a thick plate. Aluminum is very easy to drill.

Uhm maybe is better if i take a 40x40cm (or better 50x50) thick plate to set all the optical stuff and make another "floor" for PSUs and other stuff.
maybe there will be space to add another red module in future.
This is the layout i planned

http://img204.imageshack.us/img204/5...orgyxa7.th.jpg

What about lenses of red module: do you mean the internal lenses or to add correction lenses in beam path?

Hi Mille

The problem with most of the red lasers out there (and I think you have a Laser-Wave red - am I right? ;)) is that the diodes all produce fat beams. Its a limitation of the current technology and makes life difficult for us. You will probably find that you wont be able to focus the red much better - I believe the physics involved will give you more divergence if you make the beam smaller and less if you make it bigger. (anyone more informed please correct me if im talking rubbish) As far as Im aware most higher power reds are made by having a single chip with multiple emitters which is why they are very square in beam profile and can have a striped appearance. The biggest problem is getting them through the dichros and onto the scanner mirrors. You have a GBR dichro if it is a Laser-wave one and passes red and reflects green in which case you can if you are careful get all of that red through - as I have done it myself with a Laser-Wave red laser and the same dichro (15mm).
I would also recommend the 2 level approach. I have a Laser-Wave demo Projector that has red green and blue lasers & 20K scanners and is built on a 2 tier 500x250mm base - its pretty roomy without it being too wasteful of space.
Good luck with your project and keep us informed of the progress - post pics - we like pics :)

Rob

Yes is all stuff i've got from Bridge of LW.
Ok then i'll keep the red beam as it is and try to collimate.
What about multiple red modules joined togheter with a PBS cube?
Is there some prerequisite on laser modules ar anything will work good?

Thanks to everyone for all the answers, this is a real good forum :)

Quote:

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Originally Posted by Mille

Is easy to make holes in alluminium with a vertical drill?
Thanks

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Very easy and it loves high speeds. The only problem is that the bits tend to stick to the tool if you don't have a carbide tipped one. Use Diesel fuel to prevent it. Also applicable for threading tools.
Magnesium alloys are even better and lighter but harder to find.

Mille
The only thing you will need to join with a BS is another laser with polaisation at 90 degrees to the first. If ordering 2 lasers from Bridge (or through any LW agent) you can have them made to be a matched pair (I have some on order like this right now). However if the module you have is 'standard' then I guess bridge will be able to sort out an opositley polarised module when you are ready. The alternative is to mount one of the lasers at 90 degrees to the baseplate.

Rob

Hallo Mille and Hallo to all ! :)

Take a look of my first RGB setup I done a couple of months ago...
http://www.photonlexicon.com/forums/...ead.php?t=4815

maybe it could give you some idea....;)


Here I am, after a long time of silence, to give you news about my RGB baby...
I proudly introduce you... Its remake!
I changed the case set: It is not a "double floor" anymore, it's a "one-floor only" now.
I added a strong couple of handles, so I can transport it easier...

I know Mates...I know...
Maybe it isn't so sexy to see..... but.... It's what inside that counts!:D

Infos now...
Dimensions: 40x60x15 cm (15,7x23,6x5,9 inches)
Aluminium baseboard weight (1cm thickness - 0,39inch): 6,5kg (14,3 lb)
Total weight: 18 kg (circa) (40 lb circa)
Fuse values (all "quick-cut" type, 220V):
1A each PSU's;
500mA for fans;
650mA for galvos PSU.
On the main switch: 2,5A

I hope this can be helpful for you:D
Enjoy pics!

Greets to all

Steve

Hey Steve thanks for your pics and infos: it will be very usefull :)

Quote:

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Originally Posted by workaholic_ro

Very easy and it loves high speeds. The only problem is that the bits tend to stick to the tool if you don't have a carbide tipped one. Use Diesel fuel to prevent it. Also applicable for threading tools.
Magnesium alloys are even better and lighter but harder to find.

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Ehh... I use ethanol when i drill or make threads in aluminium. It works great to lubricate and prevents the material to stick to the tools. A LOT less messy than diesel as it just evaporates and completely dissapears by itself...

Quote:

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Originally Posted by Danny

Ehh... I use ethanol when i drill or make threads in aluminium. It works great to lubricate and prevents the material to stick to the tools. A LOT less messy than diesel as it just evaporates and completely dissapears by itself...

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Very useful information. Can you detail a bit, what concentration ?
((another major advantage is that it saves the money for the drink after finishing the work; we can drink the lubricant instead :D))

I got a 16 x 12 x 1/4 " aluminum plate. I'm using it all plus I'll have to add a sub floor for power supplies and whatever.
I have white and am mounting the galvos now. Allignment is proving to be a bItCh !!!!!

My Dicro set from Bridge runs G, R, B -- I need all the red I can get using an LOC.

Mike

Mike
Have you seen this....?
http://www.photonlexicon.com/forums/...ead.php?t=3390

Hope it helps

Rob

Hi Mille,

Just another thing:
Your case will be closed completely if it's finished, is it?
The two used fans are not working if mounted according to your pics.
They are all blowing inwards or all blowing outwards.
This is wrong, one must blow in and the other blow out.
It's the only way to create an airflow in a closed case. :)

A.

Quote:

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Originally Posted by MambaFreak

Hi Mille,

Just another thing:
Your case will be closed completely if it's finished, is it?
The two used fans are not working if mounted according to your pics.
They are all blowing inwards or all blowing outwards.
This is wrong, one must blow in and the other blow out.
It's the only way to create an airflow in a closed case. :)

A.

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Ehm i think you got the wrong person :)

Yes, I mean Steve Milani, the other laserist from Italy. :cool:

Quote:

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Originally Posted by workaholic_ro

Very useful information. Can you detail a bit, what concentration ?
((another major advantage is that it saves the money for the drink after finishing the work; we can drink the lubricant instead :D))

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Well I use a kind of rubbing/fuel/denaturated type of alchohol. I think it's about 95% ethanol. Try it the next time you are drilling/cutting/threading aluminum. It is VERY effective as lubricant and makes everything a lot easier. AND there is no need for cleaning up afterwards! By the way: I think you would get sick if trying to drink this stuff... :p

Oh, one more thing. Used LOW speed when drilling. Otherwise the alchohol will just fly of the drill, and aluminum will stick to it, and everything will get uggly, and all hell will break loose when you destroy the piece you been working on for the last 3 hours, and, and, and... :mad:

Quote:

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Originally Posted by MambaFreak

Yes, I mean Steve Milani, the other laserist from Italy. :cool:

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Hi Mamba!
Glad to read you.
You said right. One fan blowing inside, another one blowing outside.
This is one of the possible and logical solutions... but...

While I was mounting fans I thought: the output hole, in the front, has not any glass, it is "open-to-air".
Well... I put two fans that blowing inside, so I force the warm flow of "exhausted" air to go out through from the frontal hole:p
I also thought: doing so I can have optics and mirrors always clean because smoke, dust and other dirty things cannot enter through inside from the frontal hole because would be "countercurrent" .
In fact with two fans that pumping air inside, the case is like "pressurized" toward the outside:D
I hope to have explained well the concept.

Kindest Regards and a perfumed rose to you for gift.:)

Steve

Ok i have another question :)
How do you adjust height in laser modules and optics?

Better to set everything at the same height with additional plates, or simply adjust heights and collimate the beams with mirrors and dichros?

I chosen to place an additional plate, adjustable in height by filleted bars, under each component.
This is the easier solution.:)

All the best

Steve

Ok a little update on my scanner with some picture too :)

http://img377.imageshack.us/img377/7444/hpim1592gl1.jpg

http://img407.imageshack.us/img407/5672/hpim1593fu8.jpg

This is the scanning working in progress :p
I've setted only the optical elements.
The other stuff is only positioned without screws and nothing.

http://img220.imageshack.us/img220/8922/hpim1594re4.jpg

And this is the control "temple" :p

I have a question: i noticed that green laser seems to be underpowered when is set to idle for some time.
If i use frames with only red (or just a little green) for a while, right after that the yellow frames is more toward orange, and become a bright yellow only after some seconds (maybe a minute).
Is this common?

Nice!
You're on the right way!:)
It seems a very clean setup also.
Remember.. hurry is the worst enemy.

Good job Mate!

I was always wondered why there is a need to invent a new circular wheel.
There is a perfect and simple lasersetup. And remember :every beam bending will cost you power.
http://laseremitter.com/pix/rgblaser.jpg

Plus those adjusting platforms will not be steady enough and will not allow proper cooling!

Quote:

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Originally Posted by Dr Laser

I was always wondered why there is a need to invent a new circular wheel.
There is a perfect and simple lasersetup. And remember :every beam bending will cost you power.
http://laseremitter.com/pix/rgblaser.jpg

Plus those adjusting platforms will not be steady enough and will not allow proper cooling!

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Cool... all that info would have been usefull some week ago when i asked some tips in building the scanner :p

Btw i took some pictures of the ilda test pattern.

http://img233.imageshack.us/img233/8941/hpim1599he2.jpg

http://img134.imageshack.us/img134/3914/hpim1603ti2.jpg

How do you think is the galvos tuning?
I'm oriented to do beam shows more than graphics...
Theres some geometrical correction (the sides are little bent)

Uhm...
I see...
This is a job for Adam (Buffo)...
I think nobody can help you better then him;)

Quote:

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Originally Posted by Mille

I have a question: i noticed that green laser seems to be underpowered when is set to idle for some time. If i use frames with only red (or just a little green) for a while, right after that the yellow frames is more toward orange, and become a bright yellow only after some seconds (maybe a minute). Is this common?

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Yes, unfortunately it is common. It's most likely caused by "jellybeaning" of your green laser. DPSS lasers (especially ones with inexpensive drivers) sometimes exhibit power fluctuations when they are modulated rapidly. The problem is related to poor feedback on the tec controller and a failure to keep some "idle" current flowing through the diode (below lasing threshold) when the laser should be off. The solution is to replace the driver module. (This sometimes means buying a whole new laser.)

There is a partial solution you can try, however. Bill Benner published a schematic for a "color smoothing and delay circuit" that you could install on your red laser. This will delay the modulation of your red so that it more closely matches the rise time on your green. That, coupled with a better green driver, should eliminate your problem entirely.

Quote:

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Originally Posted by Dr Laser

I was always wondered why there is a need to invent a new circular wheel.

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Because of a hundred other variables that apply to a hobbyist-built projector that don't apply to one made in a factory. Such as, not wanting to have to machine custom shims for each laser to get the beam heights right, and not wanting to deal with the hassle of flaoting tables, so deciding to add an extra bounce to each beam path and doing the alignment with mirror mounts instead. Or having the perfect case (for free) to use for your projector, but it's too narrow to fit the lasers in the classic side-by-side arrangement shown in your picture, thus requiring some other layout.

Quote:

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And remember: every beam bending will cost you power.

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In that case, why do you have the green laser bouncing off a mirror in your picture? You could mount it sideways (parallel with the main beam path) and omit one bounce!:p (Just like my original RGB layout.) ;)

Eh - rules need to be broken once in a while, either to make the design easier to build, or to make it fit, or for any of a number of other reasons. And really, if you have good mirrors, you'll only lose around 1% per bounce on a first-surface mirror. That's an insignificant amount of power. Adding a couple extra bounces (to make alignment a snap) is a good trade-off, assuming you have the space in your projector.

Quote:

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Plus those adjusting platforms will not be steady enough and will not allow proper cooling!

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I disagree completely. My new projector has platforms of roughly the same thickness and they are *rock* solid. Even after the projector bounced around in the back of my jeep for over 9 hours, the alignment never moved. (And I've recently checked my alignment over a 400+ foot throw, so I mean it when I say it's spot-on.) The key is having the floating tables mounted to a baseplate that won't flex. The lasers themselves can be mounted on thinner plates because the weight of a single laser is not enough to bend them.

Likewise, cooling is not affected by the amount of thermal mass, but rather the surface area. He'll be just fine without any forced air movement on that layout up to at least a half watt of total output, based on my personal experience. I've built two other projectors that had similar layouts with no problems (and no forced air cooling either). More power than that and he might need to add a fan to blow under the floating tables, but he'll still be just fine.

Finally, back to Millie's scanner tuning. I need to know what angle you're projecting at, and at what speed. Looks like you're either scanning too fast or too wide. Otherwise tuning looks reasonably good. Before you tweak anything though, we need to be sure you're in the ballpark for your scanners.

Adam

Quote:

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Originally Posted by Dr Laser

Plus those adjusting platforms will not be steady enough and will not allow proper cooling!

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I addition the laserwave module with the internal fan can be operated all day long without a heatsink as all the cooling is self contained

Rob

Quote:

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Originally Posted by buffo

Finally, back to Millie's scanner tuning. I need to know what angle you're projecting at, and at what speed. Looks like you're either scanning too fast or too wide. Otherwise tuning looks reasonably good. Before you tweak anything though, we need to be sure you're in the ballpark for your scanners.

Adam

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The scanning speed is 20k... if i reduce it some the circle in test pattern is kinda matching the square.
I don't really know about the scan angle: do i have to misure the distance from wall and the side of the image? :)

Quote:

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Originally Posted by Mille

The scanning speed is 20k... if i reduce it some the circle in test pattern is kinda matching the square.

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Yeah, that's to be expected. Ok - so you've got ScanPro20's and your running them at 20K. Good. Now we need to look at the scan angle.

Quote:

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I don't really know about the scan angle: do i have to misure the distance from wall and the side of the image? :)

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Yeah, you do. Here's a link to a chart that will help you calculate your scan angle. Basically you measure the distance from the scanners to the wall that you're projecting on, and then measure the width of the pattern.

Here's a quick way to check: Divide the distance by the width, and multiply by 100. If you get a number larger than 14, you are scanning too wide.

The ILDA test pattern is designed to be scanned at 8 degrees. Some scanners can manage a few more, say 10, or even 11 degrees, but if you scan it too wide, the center circle will not touch the square and you'll see other artifacts start to crop up.

Set your scan angle to 8 degrees and take a picture of the ILDA test pattern. Then take a picture of the LaserMedia test pattern. Finally, reduce your scan angle to 5 degrees and take another picture of the ILDA test pattern. That will tell me a lot.

Adam

Ok just a question: how can i set the scanning angle?
I need to make adjustment on scanner boards, or i do it simply reducing the image width in software's geometric correction?

Normally you do it in software. You would need to reduce the width and the height by the same amount, of course.

If you *can't* adjust it using your software, then you can try reducing the input gain on the scanner amps. (Note: not the servo gain!)

What software do you use?

Adam

Quote:

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Originally Posted by buffo

Normally you do it in software. You would need to reduce the width and the height by the same amount, of course.

If you *can't* adjust it using your software, then you can try reducing the input gain on the scanner amps. (Note: not the servo gain!)

What software do you use?

Adam

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Ok... when i got home i'll try to get some picture with a 8 degrees angle.
Im using the pangolin FB3 software: so the LAstudio ones and livequick.

Ok i did some shot of the ILDA test pattern and the Lasermedia pattern at a scan angle of 8 degrees (20k scanning).
Ehm... i forgot to do a test at 5 degrees... :(
I'll do it tomorrow.

http://img392.imageshack.us/img392/4931/hpim1606jx7.jpg

http://img388.imageshack.us/img388/4271/hpim1607cb3.jpg

:)

Those exact same scanners can do a nice ilda TP if tweaked
See image Looks a bit ropey but thats cos the screen is a towel! @ 20k & I think about 15 degrees (dont quote me on this)

Rob

Hi Millie;

OK - now we're getting somewhere! Those pictures are enough. As you can see, at 8 degrees, the circle is outside the square. But when you get beyond 8 degrees, at some point you reach the limits of the scanners. At that point, the circle stops getting larger (but the rest of the pattern continues to increase in size). So the reason your earlier pictures looked messed up is because you were trying to scan the ILDA test pattern at too-wide of an angle.

Ok - you need to tune, but you're close. You've got a little bit too much gain. (which is why the circle is outside the square) My suggestion would be to decrease the scan angle *just* a tad more from the 8 degree position. (Want to be sure you're not over-driving the scanners.) You can tune at 3 degrees if you want, but trying to tune at 12 degrees will give you problems.

Also, having a longer throw (distance from the scanners to the wall) will help you tune better, since you'll see subtle changes in the test pattern more easily. (Especially the over and undershoot on the corners of the inner square.)

On to the tuning: First you need to dial back on the servo gain on both amps just a bit. The circle should get a little smaller, and the overshoot you see on the center square should get smaller.

Now dial back on the HF damping. You want to bring it down until you see some undershoot, and then add just enough to bring it back to the dot on the corner.

Now dial back on the LF damping. Again, take it down until you have overshoot, then add just enough to bring it back to the dot on the corner.

Keep doing these three steps on *both* amps until you get the circle just touching the center square. Then check the LaserMedia test pattern and make sure that the two diagonal re-trace lines are right on top of one another.

Note: You may want to reduce the tuning a few extra steps to get the circle *smaller* than the center square, and then tune *UP* from that point. Some people find it easier to tune when they are increasing the gain first, then the LF damping, and finally the HF damping, in that order. If you find it's easier to remember what you're doing when you're going "up" like that, then by all means try it.

When you're done, you should end up with something that looks like this:

http://www.photonlexicon.com/gallery...2/IldaTest.JPG

This pictures is from the set of ScanPro 20's that I reviewed earlier in the year. The wavy side of the outer square is caused by the projection screen (a black sheet) being blown around by the ceiling fan, and is not an artifact of the scanners.

One final observation - I'm very surprised that Rob was able to get 15 degrees out of his ScanPro20's. That seems really wide... I've gotten 11 degrees out of them, but that seemed to be the absolute limit - at least when scanning the ILDA test pattern. EDIT: Just noticed that Rob said "don't quote me on this", so maybe he was scanning at around 11 degrees after all.

Bottom line - if you get 8 degrees, you're fine. Anything you get beyond that is gravy.;)

Adam

Ok
first of all, thanks Adam for the kind help :)

I will tune galvos later when i have enough time to spend on it :)
I have another question about the scanning angle.
Galvo tuning is done at 8 degress then, but can i scan at a wider angle?
If i scan at around 20 degrees (if i don't do any geometric correction) the image will be just more flickering, or can i damage the galvos too?

What's the maximum angle and scanning rate i can achieve with my scanners?

Hi Millie;

The ILDA test pattern is one of the most demanding images you can scan. It's intentionally designed to push the scanners. Would you believe that the center circle is actually supposed to be a 12-sided polygon that lies completely outside the square? The scanners have no hope of ever reaching those points - they're just too far apart - but it makes it easy to tune them while they are under maximum acceleration.

You can normally scan images at around 20 to 30 degrees with no problems. If you start to see distortion in the image, then you need to back off your scan angle a bit. But when you TUNE your scanners, you need to be sure that you aren't scanning too wide, or you'll never get the tuning right.

As a general rule, flicker is a function of scan speed, not scan angle. So you probably won't notice any more flicker if you scan wider.

You *can* damage your scanners if you push them too hard. But it's not something that will happen in a matter of seconds. You'll know that you're pushing them right away, because the image will look terrible. Corners will be rounded off, circles will start to look skewed, and the whole image will just look bad. If you keep running the scanners like that, they will get hot, and in an extreme case they could fail. But you'll have time to lower your scan angle long before that happens.

Things to watch out for: If you hear your scanners making a screeching sound, that's bad. If you see the image waver and start to develop funny curves in otherwise straight lines, that's bad. If you start to notice funny curved tails on the ends of lines, that's bad. In all three cases, turn your scan angle down a bit and the problems should go away.

As for an absolute scan angle limit, that's hard to predict, because different files can be scanned at different angles. As a general rule, the more complex the graphic, the lower your scan angle should be. I've pushed those ScanPro 20's to beyond 40 degrees on simple images.

Also, if you plan to scan mostly fans, tunnels, and beam effects, then you can tune them for a lower speed (like 10K or 12K) and you'll be able to scan even wider. But of course, lower speed means things will flicker more. (Flicker isn't a problem with simple beams, but it becomes an issue with graphics.)

Bottom line - start at 20 degrees and then just watch the image and adjust your scan angle accordingly.;)

Adam

Sorry for my language. Buffo actually pointed this issue and I agree.
Let me explain why I'm strongly against those type of laser mounts. If projector will stay in one place and will never be moved then thy are fine. But if you're planing to transport it you will run into realigning-everytime issue. The best way is to measure the height and get a blocks of aluminum little bit smaller then the measure and then get a very small sheets of aluminium to lift it to proper hight. This way it'll be solid and do better with cooling.

Quote:

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Originally Posted by Mille

Cool... all that info would have been usefull some week ago when i asked some tips in building the scanner :p

Btw i took some pictures of the ilda test pattern.

http://img233.imageshack.us/img233/8941/hpim1599he2.jpg

http://img134.imageshack.us/img134/3914/hpim1603ti2.jpg

How do you think is the galvos tuning?
I'm oriented to do beam shows more than graphics...
Theres some geometrical correction (the sides are little bent)

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Ok i little update with some pics of the scanner in action :)
If i find a vodeocamera from my friend i'll post a video too :p

http://img392.imageshack.us/img392/3259/94925886bw8.jpg

http://img392.imageshack.us/img392/4962/70977289jg4.jpg

http://img55.imageshack.us/img55/3734/91417714vm2.jpg

Milie
That last pic is beautiful - just beautiful!
Good work

Rob

Quote:

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Originally Posted by stanwax

Milie
That last pic is beautiful - just beautiful!
Good work

Rob

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Drrrrroool......lovely beams and nice build ....keep them pics coming!;)

nice pictures....!!!!

Cool

You seem to be losing alot of red (projected up from the galvo's)

Yes i'm loosing some of the red cause of the fat beam :p
And btw the Y scanner is oriented to point the beam up right now, so i loose a little more.

Ok i finally found a videocamera to make a movie of my scanner in action.
The quality is kinda horrible... is the best i could do :p

http://www.youtube.com/watch?v=Xxw8B...e=channel_page

This is the link (i don't know how to embed it)
I used some clips of shows included in FB3 package :)

Looks like the ANOTHER WORLD SHOW....

:-)

Nice vid