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Thread: Advice Please

  1. #26
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    Quote Originally Posted by Shadow View Post
    There's a small science museum that has a dark room with a gitd wall and a light on the other end. It's meant to show your shadow against the wall but it's a great way to play around with a portable.
    Well that's a great idea! My understanding is that these walls are generally painted with strontium aluminate and erased with lots of deep red (~700nm). A big wall of strontium aluminate is pricey. A section of a back wall that I did with small particle strontium aluminate measuring 4 feet by 8 feet cost me more than US$250 in paint to get nice even coverage.

    Thanks for the heads up on the pbs cubes and dichros. I would have never known that until it was too late. I probably wouldn't have even suspected the cubes were inadequate. I came into the hobby when the 8x diodes were just coming out. I still got the sled it came from actually. When I saw that color I was amazed. It has such a unique glow to it. It really is an amazing wavelength.
    Those 9mm 405 diodes turned out to be multimode didn't they? Song song was selling those on facebook.
    I didn't see the diodes that you referred to. I've been using DTR's 16x 405nm diodes which are single mode or very close to it. Those can be run at 750mW each (more over a short duration) which is more than adequate for drawing on GITD paint. Too much power in fact leads to poor drawings as the 'flare' from the beam charges the areas around what you are drawing. I have blown several of these diodes however. I know they are ESD sensitive, but it doesn't appear to be my problem. Either back reflection or just long drawing times at high powers are my current (pun intended ) suspects.

    -David
    Last edited by dkumpula; 02-10-2017 at 04:28.
    "Help, help, I'm being repressed!"

  2. #27
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    Hi Guys :-)

    Photos of the lasers insides.

    IMG_0663.jpg IMG_0668.jpgIMG_0664.jpg

  3. #28
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    Humm.... anybody else seeing what I'm seeing? Looks like a red wire to 1 red diode, a blue wire to 1 blue diode and a green wire to 1 green diode. I sure don't think this is a combined 650 and 638. I'm kinda thinking the position of that lens pair is a part of his issue.
    PM Sent...

  4. #29
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    Yeah, agreed Brad. That appears to be one corrected multimode red diode. Even if the unit had some novel way of combining two diodes (one 650nm and one 638nm) with some kinda tiny cube or odd knife-edging set-up, it doesn't make sense that they were powered by one driver. In addition, they wouldn't likely correct the same as set-up with one set of lenses.

    I suspect that the manufacturer probably was sourcing either a 650nm OR a 638nm, which ever one was cheaper or more readily available at the time.
    "Help, help, I'm being repressed!"

  5. #30
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    Agree...only see three diodes there...multimode capless red expanded with 2 spherical telescope (nice hi-res pics btw!)..so fake PJ specs? one red only.
    Maybe problem on green, can you measure its power?

  6. #31
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    Hi all
    Some very interesting reading thanks for sharing. I don't have any instruments that I can measure the Green with. How would I get a reading ?

    Also I had a go at the make yellow trick. And the colour mix did improve.

    But the RED and BLUE sliders on the colour mixing are hardly on Green almost to the top.

    White is now much more visible on the images.

    I'm now starting to realise there's a lot more to a laser projector when it come to the science of getting the ingredients correct for a quality show.

  7. #32
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    It's amazing too, what is really "white". It's not uncommon to have a projector you think has a nice white..... until one day... you have it running alongside some other projector with a better white and suddenly you start thinking yours is crap.
    PM Sent...

  8. #33
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    You've definitely got just one red diode. So the projector specs are incorrect. Possible that they sell it with either 650 *or* 638? Maybe that's where the marketing info got fouled up.

    In any case, agree that you may also have a problem with your green. If both the red and blue power sliders are set super low to make a decent white, that definitely points to low green output.

    Based on the output power listed for the projector, you would expect to have to turn the blue way down, and maybe turn the red down just a tiny bit to compensate for the fat beam.

    Still wondering what they're doing with the standard lenses in the telescope arrangement. Common sense would say they're trying to reduce the beam width of a 650 nm red, but what you gain in beam diameter you lose in divergence, so that really wouldn't be smart. And if it's actually increasing the beam diameter (assuming it's a 638 nm diode), that also doesn't make sense, since a singe 638 nm diode can be easily matched with a 520 nm green and a 445 nm blue by using *cylindrical* lenses to correct just the fast axis.

    Might be a good idea to let Francis (Laserworld) chime in here. He should be able to explain what was originally installed in that unit.

    Either way, my guess is that you'll need a new green at least, and you might want to replace the red with something more powerful and with better beam quality.

    Given the compact nature of the projector, if you want to keep everything in that same housing you'll have to replace just the diodes and re-used the existing barrels and mounts. That's a good bit of work for someone who has never handled a laser diode before.

    Strongly suggest you attend the next UKLEM and chat up some of our English members about upgrading your projector. One of them may be able to offer some assistance. At the very least, they should be able to suggest a local supplier for the parts you'll need. (DTR's laser shop has the diodes, but you'll get stuck paying all kinds of import taxes because he's in the USA and you're in the UK.)

    Adam

  9. #34
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    Quote Originally Posted by Bradfo69 View Post
    It's amazing too, what is really "white". It's not uncommon to have a projector you think has a nice white..... until one day... you have it running alongside some other projector with a better white and suddenly you start thinking yours is crap.
    What? You own EVERY projector. If you don't like one just swap for another.
    "Help, help, I'm being repressed!"

  10. #35
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    Quote Originally Posted by dkumpula View Post
    What? You own EVERY projector. If you don't like one just swap for another.
    (mashing "like" button)
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  11. #36

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    I didn't want to derail this thread any further so I made one for 405 discussions. I didn't see any in the subforums for 405 either, just a few bits here and there. http://photonlexicon.com/forums/show...519#post335519

    About A1XDs projector: The green certainly sounds like it's done for and in need of a replacement. You can get dpss and diodes fairly cheap but the red part of the projector is odd. If it's 635 then that could mean a multimode diode is used with some kind of beam expander right? Wouldn't that account for the oversized beam?

  12. #37
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    Guys, remember post 10 though. This is happening in BOTH projectors which leads me to think a bad original configuration when this particular model was created. It's not just one projector that has this output. Odd to be sure, since one would think a manufacturer would know better but, then again... a manufacturer should know the difference between "one" and "two".
    .
    Adam, you mentioned Francis. This is a LKH, (Laser Know How). Are we certain this is just simply a re-branded Laserworld? I admit it does LOOK like one so that may be correct. I don't know the correlation between LKH and Laserworld but it's entirely possible, as I have bought a used Lightspace from LKH with LKH stickers on it. But it was sold to me AS being a Lightspace projector in the first place.
    .
    Humm - own every projector? You run more at any given time than I do. ..... I just have more "backups". The day is getting close though, where I am pulling everything out and getting a picture. Gonna make me a little sick I think though. I suspect there are more things that "lase" than I am actual years old....
    Last edited by Bradfo69; 02-13-2017 at 02:06.
    PM Sent...

  13. #38
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    Your correct, both projectors have the same issue. I purchased them April last year.
    Im still tempted to contact Gary at Laser Know How and ask if they can change the diode spec so the units have a better balance and still achieve a decent output.
    Do any of you guys know Laser Know How ?

  14. #39
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    Quote Originally Posted by Bradfo69 View Post
    The day is getting close though, where I am pulling everything out and getting a picture. Gonna make me a little sick I think though. I suspect there are more things that "lase" than I am actual years old....
    Sounds like a DC LEM at Brad's place. He will provide the lasers if we provide the content.
    Watching Lasers Since 1981

  15. #40
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    It's been discussed at times. And really... it would be DELEM or, MALEM. (Delaware or Mid-Atlantic) since I'm really about 1.5 hours from DC
    PM Sent...

  16. #41
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    If you look at Laser Know How's promotional materials for the LKH 2300, they show Laserworld and Pangolin as suppliers. Based on that and the look of the exterior of the projector, I'm thinking it's a re-branded Laserworld unit. But it could be something different.

    If you can reach LKH, that would be a good start. But I'd also like to hear what Francis has to say about it. He should recognize it if it's one of his.

    Adam

  17. #42
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    Quote Originally Posted by Bradfo69 View Post
    It's been discussed at times. And really... it would be DELEM or, MALEM. (Delaware or Mid-Atlantic) since I'm really about 1.5 hours from DC
    OK we got the name out of the way. What's the date?
    Watching Lasers Since 1981

  18. #43
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    I stand corrected... The projector is *NOT* from Laserworld. It does resemble a couple different Chinese units though. (No idea why LKH is still using Laserworld's logo in their marketing materials...)

    You can still replace the green diode, and the red too if you want. You'll probably want to check the driver current first though! and I'll repeat my recommendation to get with the fine folks at UKLEM before you attempt this.

    Adam

  19. #44
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    Quote Originally Posted by A1XD View Post
    Your correct, both projectors have the same issue. I purchased them April last year.
    Im still tempted to contact Gary at Laser Know How and ask if they can change the diode spec so the units have a better balance and still achieve a decent output.
    Do any of you guys know Laser Know How ?
    I posted from my mobile before and it looks like the post went missing.

    I believe Daniel Briggs on here used to manufacture some parts for them, cases, modules etc. You could try contacting him as he may be able to help you get this sorted.

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