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Thread: Beginning laser projector build and first post, all advice appreciated

  1. #21
    Bradfo69's Avatar
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    Not really... I don't think mixing a TTL source and analog source is really an issue. You'd need to tell Quickshow what you have and it's either/or so, you'd have to select TTL by default and it would simply treat your red as TTL.

    Now... the real issue(s) (there are two) are the varying powers and the quality of the components. 2 watts of blue, 1/2 watt of red and 100-200mW of green is way, way out of a normal balance for white. The other issue is the beam diameters or each of them. Ideally.... and I'm stressing ideally, you'd want the beam diameter of all three lasers to be almost exactly the same. Think of a target for shooting or archery. The bulls eye circle would be your green beam, the blue beam is going to be the size of the first ring and your red is going to be the size of the whole damn target. (Well.. seriously... say the third ring out from the bulls eye.) That's not as big an issue with beams as it is for graphics but, it will be noticeable - especially to you, even if not to your audience and, you will quickly wish you hadn't wasted the money and will want to get something better to replace them. $88.88 and $75.89 are loose change in this whole laser endeavor. Granted, as a new person starting out, you may want to just to get your feet wet with something but, yes, you will quickly decide you need to upgrade. Now... quality of components. I actually kinda like that 2 watt blue to be honest but, I'm not terribly excited about the red and the green. Even stepping up to this might be a little better bet: http://www.ebay.com/itm/Solid-Stated...item2c99037f85 Red... that's still a hard call as that's going to be the most expensive component.

    I'd also be inclined to just put it out there in the Buy Sell thread that you're looking for some starter modules. I'm sure there a members with some used but perfectly suitable things.

  2. #22
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    Well, I'm pretty bummed out right now and I'm really hoping I didn't make a rookie mistake and fry my galvos....

    I spent all day making heat sinks out of aluminum and mounting them to the driver boards.

    The test pattern displayed for about 5 seconds before the Y stopped so I immediately shut down everything.


    Observations and possible errors:
    The drivers were warm to the touch but I wouldn't say they were too hot...
    The heatsinks were connected (this might be the problem...)

    Ugghh I'm gonna go to the zoo or something tomorrow...









  3. #23
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    Update, I took the heat sink that I made off and ran the galvos for about 10 seconds. They seemed fine.

    Mabee I've gotten a second chance and didn't fry them.
    I guess I'm going to cut the heatsink in half for starters.
    Should I be using some sort of thermal lube to transfer the heat more effectively from the steel plate to the aluminum?

    Any feedback would be great
    Thomas

  4. #24
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    Quote Originally Posted by tej2795 View Post
    Well, I'm pretty bummed out right now and I'm really hoping I didn't make a rookie mistake and fry my galvos....

    I spent all day making heat sinks out of aluminum and mounting them to the driver boards.

    The test pattern displayed for about 5 seconds before the Y stopped so I immediately shut down everything.


    Observations and possible errors:
    The drivers were warm to the touch but I wouldn't say they were too hot...
    The heatsinks were connected (this might be the problem...)

    Ugghh I'm gonna go to the zoo or something tomorrow...








    wait... are the electronics on the back of the galvo amps touching the heatsinks??
    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.

  5. #25
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    I believe the underside of the driver board had about a milimeter gap between the aluminum. (Did I accidentally make some sort of crude capacitor)
    The contact points for each amp were two screws between the matte black wall on the amp and the aluminum sheet behind.

  6. #26
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    Quote Originally Posted by tej2795 View Post
    I believe the underside of the driver board had about a milimeter gap between the aluminum. (Did I accidentally make some sort of crude capacitor)
    The contact points for each amp were two screws between the matte black wall on the amp and the aluminum sheet behind.
    what i typically do is bolt the amps directly to the metal baseplate of the projector. that provides all the heat sinking you will need.

    Click image for larger version. 

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    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.

  7. #27
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    That would be a touch too close for comfort for me. Often you only see the galvo amps attached to a projectors base plate where the two screw are on the short edge of your heat sink. The circuit board is often just standing vertically in the air - just like Swami's pic.

  8. #28
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    i would not want a 1mm spacing either, way to easy for a short, all the galvo amps i have ever seen have only the final drive parts attached to the heat sink and have standoffs that hold the board at about 3-5 mm.
    and yes to the thermal stuff, the drive parts should already have it, i would use a little on the galvo's metal to your projectors base plate
    Remember Remember The 8th of November, When No One Stood, but Kneel, In Surrender
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  9. #29
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    The build is going well, Almost all of the final parts are in shipping (diode modules, aluminum parts, dichros, psu). I'll be sure to add some pictures eventually.
    Last edited by tej2795; 06-09-2015 at 19:42.

  10. #30
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    There is a small black wire coming out of the goldenstar laser diode housing that is split at the end, just barely. I'm not quite sure what this is, but I am assuming it is a grounding wire???
    Any thoughts?

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