Need some help planning/building RGB scanner

[mliptack]

I have also been doing more research regarding CDRH Compliance and as far as E-Stop buttons I found this one:

http://cgi.ebay.com/ws/eBayISAPI.dll...OMOBOX:NEWLIST


I figured it would be wise to have the key release there, granted it'll add another step to get the show started again, but if it was pressed in the first place, I would probably have some time before I would need to start it again anyway... Knock on wood.

Do you have any suggestions on routes you guys have taken in the past to get your projector CDRH compliant? In reality I guess I am just shooting for CDRH compliance, for the added level of safety it will offer my family and so that I can say that it is CDRH compliant ... it sounds cool!

Also when it comes to data runs, where do you find the type of cable (25 pin I think) with ILDA style connectors at the end? I think I might try to go for a 100' run with a 50' extension if I ever need it.

[pbolger]

Also when it comes to data runs, where do you find the type of cable (25 pin I think) with ILDA style connectors at the end? I think I might try to go for a 100' run with a 50' extension if I ever need it.

The ILDA connectors are just parallel port plugs. I'd avoid running long lengths though - the ILDA connection is fully analogue and will suffer if you make the cables longer than a few meters. Much better to work out a way to run a long USB cable (stick a cheap computer near the projector and talk to it via wireless and VNC would be my solution to a 100' run). It's certainly possible to deal with long cable runs in the analogue domain, but in the age of $20 wireless adapters why bother?

If you bought something like the FB3 you could consider controlling it via DMX.

[buffo]

If you want discrete (TTL) outputs from a flashback controller, your only option is to use the DMX daughter board. However, remember that the LA FREAK hobbyist package comes with a stripped-down version of the FB3 controller. You don't get a memory card, and you don't get the DMX daughter card.

I'm pretty sure that you can pay the extra $$$ and get the daughter board when you buy your LA Freak package, but you'll probably need to talk to Bill Benner about it. (As for the memory card, you can buy one yourself later on if you decide you want/need one.)

Don't forget that you'll also need a DMX decoder inside your projector to read the DMX signals and trigger your discrete effects. They're not all that expensive, but it will add to the cost of the build.

Several places can make custom cable lengths for you, but I agree with pbolger; 100 ft of ILDA cable is really pushing things. If you do decide you need to use long runs, be sure and buy a "max spec" cable. Such cables have each signal wire twisted with a separate ground wire, so you have 50 total wires inside a standard 25 pin parallel cable. Cuts down on noise, but it increases the cost of the cable.

Adam

[mliptack]

So you may have read from this thread http://www.photonlexicon.com/forums/...ead.php?t=2266 that I my DT-40s arrived at my door, earlier this week (Thursday 5/17 thanks Jian!)

Well it seems I am a while away from understanding how everything is wired up, I think I have a grasp on most of it, however, I am still just a little bit worried I'll make a mistake. As for the Scanner Inputs and Outputs from the driver board that will go to the DB25 connector, what do you guys use for that? I would like to use those same type of plugs that come on the ends of all the DT-40 electronics, but would I need a crimper and all the pieces to do that? or can I buy a few ready made ones with 36" leads on them or something?

I cant seem to find my camera, however, at this stage any pictures would just be of the DT-40s in their box I'll be sure to take lots of pictures, and a step-by-step log of the process.

Thanks for your help,
Max

[mliptack]

Also I have been looking at all different options I have as far as obtaining my desired output.

In the past I have read about people using both 635nm lasers as well as 660nm lasers for more power for beams, while still having plenty of deep red available. Is this a viable path to take? Of course the downside of the 635nm lasers is their beam quality/divergence etc., but with a high power of 1watt how noticeable would such a divergence be when using it for beam shows?

This also applies to the Blue in my RGB. There are two separate blue lasers available- 457 and 473nm. 473 seems to be the most popular choice among users of PhotonLexicon. Is that because the deeper 457nm needs more power to really *shine*? While the 473nm may not be the deepest blue, but is cheaper on an actual visual output comparison?

http://translate.google.com/translat...ial%26hs%3DGmu
like demonstrated in the threads above (sorry about the poor german-english translation)

[buffo]

I haven't seen any prices for a 457 nm DPSS laser. How do they compare to 473 nm prices?

I have seen the 456 nm argon blue line, and it most certainly is a beautiful deep blue - much nicer than 473 nm, and *way* better than the ugly 488 nm Argon blue. So 457 is going to look roughly the same as the Argon 456 nm line.

If you could get the same power for the same price in each wavelength, I think I'd go with the 457 nm just to get the deeper blue, even if the eye is less sensitive to the shorter wavelength blue.

However, my guess is that the 457 nm laser is going to be a lot more expensive at the same power level. Then too, considering the fall-off of the eye's sensitivity at the high end of the blue scale, you might want *more* power if you go with 457 nm, which is going to push your costs even higher.

Another thing to consider is beam quality. One of the german sites that listed 457 nm DPSS units (200-300 mw range) said that the beam quality was "near TEM 00". Huh? How can it be "near"? Either it is, or it isn't. That laser probably has a TEM01 beam profile with the two beams very close together. I don't know if this is something that is common among 457 nm DPSS units or not, but it's certainly not ideal when you're building a laser show projector.

Then too, I don't know anyone that has a 457 nm laser in their projector. Maybe it's because we're all behind the times here in the US, but I doubt it. There's got to be a reason why 473 nm is so much more popular, and I don't think it's just because the eye is more sensitive to 473 nm vs 456 nm. (My guess is price and beam quality, but I'd love to see data to support or refute this belief.)

RE: mixing 635 nm and 660 nm... Remember that the DT-40 scanner mirrors are small. If you get a 635 nm laser with a really fat beam, you'll loose a good bit of power because part of the beam will spill over the ends of the galvo mirrors and be lost. So you'll want to pay extra to get decent beam quality out of the 635 nm laser if you go that route.

I've got a friend that has a 500 mw 635 nm laser, and he's running the 15Kpps scanners that Dave and Aijii sell. The beam coming out of the laser is round, but the beam coming out out of the projector is rectangular, because the mirrors are rectangular! He looses between 15 and 20 % of the total red power across the galvos due to the combination of mirror losses and the wasted beam that spills off the edges of the mirrors. (It's hard to get an accurate measurement, because the beam is so large to start with.) So keep beam quality in mind... It can cost you a lot in terms of output power if you're not careful.

Re: Wiring... Here is a pic of the ILDA plug that connected to the output of my old Alphalite controller. Nothing fancy; the wires from the DT-40's are just soldered to the DB-25 connector. You can move forward and backward through the gallery to see more pictures of my old setup.

If your set of scanners didn't come with a set of wires with the plastic ends on them, you can always solder some stranded wire directly to the pins on the amps (and the galvos) and wire them up yourself. (That's what I'm doing with my new DT-40 pros...)

Adam

[mliptack]

I haven't seen any prices for a 457 nm DPSS laser. How do they compare to 473 nm prices?

From some pricing data that I have the 457 is cheaper per milliwatt. About $33 per milliwatt compared to about $40. (This data is a few years old using Shanghai Dream Lasers 500mw as a comparison).

If you could get the same power for the same price in each wavelength, I think I'd go with the 457 nm just to get the deeper blue, even if the eye is less sensitive to the shorter wavelength blue.

However, my guess is that the 457 nm laser is going to be a lot more expensive at the same power level. Then too, considering the fall-off of the eye's sensitivity at the high end of the blue scale, you might want *more* power if you go with 457 nm, which is going to push your costs even higher.

If you look at that link above it says that the 457nm laser is outputting at 350mw or, and the 473nm is only 80mw, of course pictures can easily deceive when it comes to trying to guess output of a laser, but the person writing the post even says that the 457 and 473nm laser are almost identical as far as the intensity of the beam.

RE: mixing 635 nm and 660 nm... Remember that the DT-40 scanner mirrors are small. If you get a 635 nm laser with a really fat beam, you'll loose a good bit of power because part of the beam will spill over the ends of the galvo mirrors and be lost. So you'll want to pay extra to get decent beam quality out of the 635 nm laser if you go that route.

What would you say is the upper limit on beam diameter for the DT-40's?

If your set of scanners didn't come with a set of wires with the plastic ends on them, you can always solder some stranded wire directly to the pins on the amps (and the galvos) and wire them up yourself. (That's what I'm doing with my new DT-40 pros...)

Although I am completely confident of my soldering skills... I still think everything would be much cleaner if I had those plastic pieces... I think I will see if I can get any from the electrical engineer at work...

Thanks,
Max

[buffo]

I don't know the exact specs of the DT-40 mirrors, but a quick check with a sloppy ruler on the mirrors sitting right here suggests that they're about 8mm across. So, given that you have the mirror at (roughly) a 45 degree angle, I'd say you don't want to go over 5 mm beam diameter, or else you'll spill off the mirror. (Actually, anything over 5.7 mm would spill with the mirror at rest at 45 degrees... But since the mirror will move through other angles, you'll want some wiggle room there.)

This assumes the beam enters on the horizontal, and is based on the beam height being one of the two equal-length sides of an imaginary 45-45-90 triangle with the mirror being the hypotenuse. Since we know that A squared + B squared = C squared, and A=B, then a = square root of 8 mm squared / 2, or simply the square root of 32, which is roughly 5.7 mm. (If anyone has a better way to figure it, by all means jump in.)

RE: the 457 nm lasers... Interesting. I didn't know that they were so cost effective. Heck, even if the sensitivity of the human eye is low at that wavelength, it sure would be cool to have that deep blue as part of your projector. (I'm thinking of a 4 or 5 laser setup here, with 457 nm, 473nm, 532 nm, 635 nm, and possibly 660 nm.) Of course, losses through the dichros will be a bitch, and although I know Pangolin can support 6 color output, I don't know if any other packages can do that...

Adam

[allthatwhichis]

...(I'm thinking of a 4 or 5 laser setup here, with 457 nm, 473nm, 532 nm, 635 nm, and possibly 660 nm.) ...
Adam

Don't forget 405nm... 3, 4, 5... that makes 6.

[mliptack]

I don't know the exact specs of the DT-40 mirrors, but a quick check with a sloppy ruler on the mirrors sitting right here suggests that they're about 8mm across. So, given that you have the mirror at (roughly) a 45 degree angle, I'd say you don't want to go over 5 mm beam diameter, or else you'll spill off the mirror. (Actually, anything over 5.7 mm would spill with the mirror at rest at 45 degrees... But since the mirror will move through other angles, you'll want some wiggle room there.)

This assumes the beam enters on the horizontal, and is based on the beam height being one of the two equal-length sides of an imaginary 45-45-90 triangle with the mirror being the hypotenuse. Since we know that A squared + B squared = C squared, and A=B, then a = square root of 8 mm squared / 2, or simply the square root of 32, which is roughly 5.7 mm. (If anyone has a better way to figure it, by all means jump in.)

I guess if we figured out the degree off of center that the mirror moves we could find the maximum angle that the mirror would be to the laser (i would assume only a couple degrees maximum) then we could find the two dimensional mirror size from the laser's point of view. I might do that once I figure out the degree that the mirrors turn, that might be in a while... i dont even have any control over the scanners yet! (Although I should be getting the FB3 controller within the next few days!!!!!)

RE: the 457 nm lasers... Interesting. I didn't know that they were so cost effective. Heck, even if the sensitivity of the human eye is low at that wavelength, it sure would be cool to have that deep blue as part of your projector. (I'm thinking of a 4 or 5 laser setup here, with 457 nm, 473nm, 532 nm, 635 nm, and possibly 660 nm.) Of course, losses through the dichros will be a bitch, and although I know Pangolin can support 6 color output, I don't know if any other packages can do that...

Adam

heh, yeah losses would suck, and to control the beam divergence as much as possible you would probably have to put the 635nm laser as close to the mirrors as possible. Which would mean the 408nm, 457, and 473 would all be behind optics... **shudder**

Don't forget 405nm... <img alt="" title="Wink" border="0"> 3, 4, 5... that makes 6. <img alt="" title="Big Grin" border="0">

Yeah I would have to go with 408 or 409nm, gotta love that violet!