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Thread: Old TTL RGB diode build

  1. #1
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    Apr 2012
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    Default Old TTL RGB diode build

    Thought I would show off a quick projector build I made last year while I wait for some parts to come in. This projector was put together for an associate using spare components I had lying around. Quite handy for cleaning off the shelf!

    The 12V TTL RGB diode laser module I reviewed a ways back was used for the light source. For galvos, I used your standard issue 25kpps ebay galvos and for a showcard I used a Lasershark. (naturally )

    I purchased the case from Jameco. It's nice but I would have selected a case that was more welcoming of a bracket mount for future projects. Most of the mount holes were cut with a hole saw and cleaned up with a de-burring tool. A nibbler was used for the power socket.

    I CNC-ed a few blocks of aluminum to make the laser/galvo mount and galvo amplifier heatsink block.

    Nothing special, just thought you all might enjoy

    Click image for larger version. 

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    Last edited by macpod; 10-09-2014 at 19:08.

  2. #2
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    Great looking little unit!
    Now just retrofit it with DTR's Single Mode RGB Combo
    Philipp Wetter

  3. #3
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    Dec 2010
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    DC/VA metro area, USA
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    Cute! Nice assembly work.

    Does that tape really say 3mW green? If that's the same TTL module from your other thread, it seems to have aged a bit?

  4. #4
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    Mesa, AZ
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    Default

    Nice little unit!

  5. #5
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    Jan 2007
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    Florida
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    Nice clean build I'm interested in that Lasershark board. If I read that right it supports galvo x,y; 2 channel, and 3 channel for RGB lasers but one of those channels is TTL only - is that right?

  6. #6
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    Apr 2012
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    Quote Originally Posted by JRGixxerfreaK1 View Post
    Great looking little unit!
    Now just retrofit it with DTR's Single Mode RGB Combo
    I bought a set when he first started offering them (price has come down a bit since then!).

    I'm planning on making a high quality dedicated build with them which I'm hoping will take the title of "smallest full color projector" and stay that way for some time to come... time has not been on my side however.

    Quote Originally Posted by tribble View Post
    Cute! Nice assembly work.

    Does that tape really say 3mW green? If that's the same TTL module from your other thread, it seems to have aged a bit?
    I intentionally tuned it such that the max power was as low as possible while still allowing proper modulation and a white balance. The laser was detuned because I was using it around highschool students to get them interested in software/embedded software/electronics.

    The relative power levels do seem odd though don't they? I would have expected slightly more than 3mW of green to be needed to match the perceived brightness of the R and B diode.


    Quote Originally Posted by steve-o View Post
    Nice clean build I'm interested in that Lasershark board. If I read that right it supports galvo x,y; 2 channel, and 3 channel for RGB lasers but one of those channels is TTL only - is that right?
    Yup, 2 12-bit bipolar differential x and y galvo channels, 2 12-bit non-differential laser output channels, and one TTL channel.

    Artistically speaking you can control it with:
    -OpenLase and JACK - Allows you to program realtime shows via an openGL-ish setup.
    -lasershark_stdin - Allows you to pipe a stream of text command lines in to control the Lasershark (the format kinda looks like a csv file). I made this one so things like laserboy output files can easily be converted and streamed out to the LaserShark without these developers having to know how to work with USB.

    For 3d printer uses you can control it via:
    -Creation workshop
    -lasershark_3dp - Pre-alpha really.. I'm still messing around with this


    All of this is open source by the way.

  7. #7
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    Quote Originally Posted by macpod View Post
    The relative power levels do seem odd though don't they? I would have expected slightly more than 3mW of green to be needed to match the perceived brightness of the R and B diode.
    Yes, they sure do! I mean, 60x red for balance? That doesn't line up with anything I've ever seen or read. How confident are you about those measurements?

    BTW, good on ya for all of that open source laser goodness. Beautiful stuff.

  8. #8
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    Apr 2012
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    Given that it has been a whole year since I touched this I can't say with any confidence what the values actually mean. It could have been the min determined for each color *before* finding the combo that made a sufficient white color too. That would make slightly more sense.

    Whatever it was, it was definitely measured with the ophir head because that's the only measuring device I have.

  9. #9
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    Oct 2007
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    Vancouver, Canada
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    Quote Originally Posted by steve-o ---
    Nice clean build I'm interested in that Lasershark board. If I read that right it supports galvo x,y; 2 channel, and 3 channel for RGB lasers but one of those channels is TTL only - is that right?

    Yup, 2 12-bit bipolar differential x and y galvo channels, 2 12-bit non-differential laser output channels, and one TTL channel.
    I'm curious where you ran into this particular limitation ? Was is just a result of an unneeded feature for your needs and keeping costs down / number of components ? Or was it a limitation somewhere else in the design that would require a completely different approach / redesign ?

  10. #10
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    I began with the goal of making a projector with one analog laser modulated output that was relatively inexpensive.

    ...There aren't that many 3-channel dacs out there and it would be a shame to waste that 4th channel ... and for only a dollar or so more in parts I could add that second analog channel!

    ...Then I thought to myself for another few cents... I could add a ttl channel too!

    That's basically it. The fact that it's like that I must admit kinda drives me nutty although given 532nm modulates terribly anyhow perhaps it isn't that big of a deal.. and everything can be fixed in software right?! Hardware designers don't make mistakes, only features

    The next one I made will be dedicated for a 3 diode full analog setup.

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