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Thread: Galvo/Amp Upgrade

  1. #21
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    Quote Originally Posted by jdavis7765 View Post
    I thought I would be able to cut a 2x2 block of aluminum with metal blade on circular saw (metal blade), but maybe I was wrong :/.
    I have successfully cut 1/4 inch thick aluminum plate using a table saw with a carbide-tipped blade, but this is admittedly a risky task. You need to go very slow! If you overload the saw it can violently kick the plate back at you, potentially causing serious injury. Also, this only works with aluminum. Do *not* try it with steel. (Trust me on this - you will have a very bad time if you try it with steel!)

    In theory you could do the same thing with a circular saw, but again, it's risky. For sure you'd want to have the aluminum plate clamped down really firmly before you started, and again you need to go slow with the skill saw. But a carbide-tipped blade will cut through aluminum reasonably well provided you take the appropriate precautions.

    Note that this only applies to cutting plate. Cutting a 2 inch thick piece of solid aluminum is probably beyond the abilities of your average hobbyist unless you happen to have a mini mill or a really nice band saw. If you need to work with material that thick you probably want to take it to a machine shop.

    I did look at the diagram but for some reason it did not register that the one view shows the beam entering and the height at which it should enter.
    OK, but you see it now, right? The Compact 506 scanners have a beam entry height of 25 mm if you come in from the right and hit the top mirror first, or a beam entry height of 18 mm if you come in from the left and hit the bottom mirror first. (To do the "left entry" the block has to be rotated 90 clockwise.) All of this assumes that you are facing the block with the output beam coming straight at you.

    If I were thinking about upgrading the lasers at any point, is there any website that sells them you could recommend or even recommended lasers? When I say upgrade, i do not mean higher power, I quite like where I am at now. I just wonder if I can get better color from better lasers vs what I have now.
    There are several suppliers, sure, but I'm not sure exactly what you're wanting to improve.?. I thought the lasers in your projector already supported analog color modulation... If so, then you should be able to dial in just about any color you want. Or is there another problem with color that you're referring to?

    Usually when people ask about getting "better color" it's because they're looking to get rid of subtle modulation issues that can leave "tails" or other artifacts in graphics shows - particularly when parts of an image have the intensity faded down very low. Fixing issues like this is normally a matter of switching to a better diode driver for the lasers. Is that what you're talking about?

    Adam

  2. #22
    Join Date
    Nov 2019
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    West Chester, PA
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    Quote Originally Posted by buffo View Post
    I have successfully cut 1/4 inch thick aluminum plate using a table saw with a carbide-tipped blade, but this is admittedly a risky task. You need to go very slow! If you overload the saw it can violently kick the plate back at you, potentially causing serious injury. Also, this only works with aluminum. Do *not* try it with steel. (Trust me on this - you will have a very bad time if you try it with steel!)

    In theory you could do the same thing with a circular saw, but again, it's risky. For sure you'd want to have the aluminum plate clamped down really firmly before you started, and again you need to go slow with the skill saw. But a carbide-tipped blade will cut through aluminum reasonably well provided you take the appropriate precautions.

    Note that this only applies to cutting plate. Cutting a 2 inch thick piece of solid aluminum is probably beyond the abilities of your average hobbyist unless you happen to have a mini mill or a really nice band saw. If you need to work with material that thick you probably want to take it to a machine shop.
    Yeah, I got the block in the mail today and I do not think this is something I want to do on my own. I think I will just get the measurement and pop into a local machine shop to see if they can cut it for me.



    Quote Originally Posted by buffo View Post
    OK, but you see it now, right? The Compact 506 scanners have a beam entry height of 25 mm if you come in from the right and hit the top mirror first, or a beam entry height of 18 mm if you come in from the left and hit the bottom mirror first. (To do the "left entry" the block has to be rotated 90 clockwise.) All of this assumes that you are facing the block with the output beam coming straight at you.
    Yes, I see it now, should be fairly easy to measure once I get the beam height.



    Quote Originally Posted by buffo View Post
    There are several suppliers, sure, but I'm not sure exactly what you're wanting to improve.?. I thought the lasers in your projector already supported analog color modulation... If so, then you should be able to dial in just about any color you want. Or is there another problem with color that you're referring to?

    Usually when people ask about getting "better color" it's because they're looking to get rid of subtle modulation issues that can leave "tails" or other artifacts in graphics shows - particularly when parts of an image have the intensity faded down very low. Fixing issues like this is normally a matter of switching to a better diode driver for the lasers. Is that what you're talking about?

    Adam
    I suppose maybe my ignorance got the best of me. I guess what I am referring to is the blending of colors (assume this would be the effect of modulation) when comparing laser to program on the computer. I know it will not be 100 percent accurate, it just sometimes appears "off". Do you have a an example of the "tails" you referred to?

  3. #23
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    Quote Originally Posted by jdavis7765 View Post
    I think I will just get the measurement and pop into a local machine shop to see if they can cut it for me.
    With luck the beam height of the lasers will be equal to or greater than the beam entrance height for your scanners. Then you can just shim the scanner block up if needed using several layers of sheet metal, which you can cut yourself.

    But yeah, if the laser height is lower than the beam entrance elevation for the scanner block then your best bet is to take the scanner block to a shop and have them shave it.

    what I am referring to is the blending of colors (assume this would be the effect of modulation) when comparing laser to program on the computer.
    The quality of the color blending you see in the output is directly related to the quality of the laser diode drivers. If the analog modulation response of the driver is linear, you should see great color blending. On the opposite end, a pure TTL driver (so on-off modulation only) will only give you 7 possible colors. Most analog drivers show at least some non-linearity, but any analog modulation ability (even from a really cheap driver) is still going to look worlds better than TTL modulation. But yeah, better drivers = better color gradients.

    Don't forget that you can also tweak your color settings in software. Often a little software adjustment can largely correct the limitations of a cheap analog driver. For example, if you notice that your orange looks more like yellow, or if your white has a greenish tint to it, these are things you can tweak in software. Some software will also allow you to adjust the modulation curve throughout the range from 0 to 100% output, which is even more helpful.

    Do you have a an example of the "tails" you referred to?
    I had to do some digging, but I found a few examples. (Funny how people never seem to save pictures that show a problem!)

    In this post, have a look at the 3rd picture which shows a green question mark being displayed. The dot beneath the question mark has a pronounced tail where the laser did not turn off at the point when the dot was fully drawn. The is the most common example of a "tail", and it can usually be fixed by simply adjusting the blanking offset value in software. However, if you have wildly miss-matched drivers you may need to install a delay circuit to match up the response times. (This was a bigger problem back when we had both DPSS and direct-diode lasers in the same projector, but nowadays nearly all projectors use all direct-diode lasers.)

    Another, more subtle example of tails can be seen in this post. Here the effect is harder to notice, but if you look at the starting and ending points of the white line segments you can see a small yellow tail on some of them, and a very tiny blue tail on some as well. The corrected picture to the right isn't perfect, as there are still a few blue tails visible, but it's much better than the initial picture. Fixing this problem required the addition of the delay circuit I mentioned above.

    If you're experiencing tails as shown in the first example (the question mark picture), then you can probably fix that by adjusting your blanking offset. But if you have tails and/or blending artifacts that look more like the second example, then you'll either need to install a delay circuit on each of the 3 color modulation inputs to the projector, or you'll need to replace the laser drivers with ones that have superior modulation response.

    But again, before you start pricing new drivers be sure you've tried to adjust your colors in software first, because most modern laser show software includes several settings that can be used to tweak your color modulation.

    Adam

  4. #24
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    So, got my block of aluminum and machine shop said 130 dollars to cut. I went and bought aluminum cutting blade for miter saw, secured black to saw with clamp, put cinder block in between me and saw for safety and it cut through like butter. Got that done and holes drilled to mount and it seems like I have the tails you are referring to, only these appear to be cause by galvo block placement. If I slide the block toward or away from the back or front of projector, it moves to the top of the bottom. It looks like there is a sweet spot but with my limited abilities it will take quite a few attempts to get right. This leads me to think, did I get the wrong size mirrors? Should I have went with 5mm instead of 4 as it may have been easier to align? It seems to be more pronouced on red than any other color as well, not sure what that indicates as the blue beam appears to not be circular yet it looks more like a small vertical rectangle so I figure that would have more spill off on mirrors. Let me know what you all think.
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    Quote Originally Posted by buffo View Post
    With luck the beam height of the lasers will be equal to or greater than the beam entrance height for your scanners. Then you can just shim the scanner block up if needed using several layers of sheet metal, which you can cut yourself.

    But yeah, if the laser height is lower than the beam entrance elevation for the scanner block then your best bet is to take the scanner block to a shop and have them shave it.



    The quality of the color blending you see in the output is directly related to the quality of the laser diode drivers. If the analog modulation response of the driver is linear, you should see great color blending. On the opposite end, a pure TTL driver (so on-off modulation only) will only give you 7 possible colors. Most analog drivers show at least some non-linearity, but any analog modulation ability (even from a really cheap driver) is still going to look worlds better than TTL modulation. But yeah, better drivers = better color gradients.

    Don't forget that you can also tweak your color settings in software. Often a little software adjustment can largely correct the limitations of a cheap analog driver. For example, if you notice that your orange looks more like yellow, or if your white has a greenish tint to it, these are things you can tweak in software. Some software will also allow you to adjust the modulation curve throughout the range from 0 to 100% output, which is even more helpful.



    I had to do some digging, but I found a few examples. (Funny how people never seem to save pictures that show a problem!)

    In this post, have a look at the 3rd picture which shows a green question mark being displayed. The dot beneath the question mark has a pronounced tail where the laser did not turn off at the point when the dot was fully drawn. The is the most common example of a "tail", and it can usually be fixed by simply adjusting the blanking offset value in software. However, if you have wildly miss-matched drivers you may need to install a delay circuit to match up the response times. (This was a bigger problem back when we had both DPSS and direct-diode lasers in the same projector, but nowadays nearly all projectors use all direct-diode lasers.)

    Another, more subtle example of tails can be seen in this post. Here the effect is harder to notice, but if you look at the starting and ending points of the white line segments you can see a small yellow tail on some of them, and a very tiny blue tail on some as well. The corrected picture to the right isn't perfect, as there are still a few blue tails visible, but it's much better than the initial picture. Fixing this problem required the addition of the delay circuit I mentioned above.

    If you're experiencing tails as shown in the first example (the question mark picture), then you can probably fix that by adjusting your blanking offset. But if you have tails and/or blending artifacts that look more like the second example, then you'll either need to install a delay circuit on each of the 3 color modulation inputs to the projector, or you'll need to replace the laser drivers with ones that have superior modulation response.

    But again, before you start pricing new drivers be sure you've tried to adjust your colors in software first, because most modern laser show software includes several settings that can be used to tweak your color modulation.

    Adam

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