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Scratch Build – In Progress Rear-DI Multitouch Table - 42.42" - Update 7/19

Discussion in 'Project Logs' started by tomclancey, 8 Jul 2011.

  1. tomclancey

    tomclancey What's a Dremel?

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    Hello all! It's Anthony again with another project! I started this along with my Poplar/Pine Computer Desk project. (Yay for shameless plugs!)

    This time though a buddy is helping me construct it! It all began when we were starting up a D&D group and I saw something that caught my eye. RPMaptools! It seemed to revolutionize the way people could play D&D. Then I saw someone use a multi-touch screen and I'm thinking to myself, I found my new project!

    Initially I had mulling around my head an FTIR (frustrated total interior reflection design) where an array of IR LED's would be lined up along side 3/8" acrylic (or 1/2") and blast IR light throughout the acrylic with no leakage.

    The only problem is they don't detect fiduciary markers, and it would cost almost 3 times as much. $120 for the LED's (on the cheap end) and $98 for the acrylic. Ouch.

    The more common alternative that can do both multi-touch fingers and fiducial markers is Read-DI! Or diffused illumination.

    Essentially it works by covering the entire bottom side of the with IR light (I'm using four 48-LED arrays that are normally used for outdoor security lights). From what I've read and seen it's a lot cheaper then using IR LED bars. That would set me back almost $300 in strips alone!

    Project costs so far:
    Projector:
    Dell 3300MP - FREE
    Computer:
    Junker Dell PC - FREE
    IR lighting:
    4x 48 IR LED array - $57
    Lumber:
    4x 1" x 12" x 6' pine-sheets - $25
    4x 1" x 2" x 3' cherry - FREE
    4x 3/4" x 30" x 48" plywood - FREE
    1x 3/4" x 60" x 40" plywood - FREE
    1x 1" x 2" x 98" maple - FREE
    Compliant surface:
    36" x 5' Vellum - $17
    Acrylic:
    1x 3/16" x 30" x 30" - $27
    IR Camera:
    1x PlayStation 3 EYE - $25 (IR converted!)

    It all comes out to about $151! Not bad for something like this.

    (Oh, if anyone lives in the tri-state area, Queen City Polymers is an awesome acrylic distributor! Great prices, and they get orders done fast!)

    So yeah, enough of me blabbering, here are some pictures!

    Here are some renders of the desk:
    [​IMG]
    [​IMG]

    What the renders don't show is the mirror, projector and PS3 Eye. The project will mount under the screen, bounce onto a mirror and project through the acrylic onto the vellum. The PS3 Eye which has been converted to only capture IR light with pickup any hot spots left by fingers and the fiducial markers. (The hot spots show up because they reflect IR light instead of it diffusing into the surrounding area.)

    Photos!
    The cherry "clamps" that will hold the vellum taught across the acrylic.
    [​IMG]
    Measuring depth of the acrylic on the shelf piece.
    [​IMG]
    Routing the last shelf.
    [​IMG]
    Still routing!
    [​IMG]
    All four done.
    [​IMG]
    All four of the edge pieces cut. Those were a pain! And we still had fitting issues so I recut them later.
    [​IMG]
    Shot of the jig and rip saw used to cut the angled table-top pieces.
    [​IMG]
    Dry-fitting of the top pieces. As you can see, lots of errors! Those were fixed-ish later.
    [​IMG]
    Post-fix. Much better! And we can reuse the scrap for joinery. Win-win!
    [​IMG]
    Oh, it was also my birthday today (well, yesterday technically). The big 18!
    [​IMG]
    Friend and I screwing on the shelf pieces for the acrylic. Got the corner-braces attached too.
    [​IMG]
    Top done!
    [​IMG]
    And there's a behind shot! Got the 4 corner braces (going to add some in between them and the corner of the acrylic though). The 4 "shelf" units and the 8 stops for the table-legs.
    [​IMG]

    Stay tuned for more!
     
    Last edited: 20 Jul 2011
  2. SenseiOnIce

    SenseiOnIce What's a Dremel?

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  3. Rai

    Rai What's a Dremel?

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    Interesting idea. I look forward to seeing it completed.

    Is anyone else having trouble viewing the images in this thread? :(
     
  4. St3ph

    St3ph What's a Dremel?

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    Happy Birthday and nice start ;)

    Not at all...
     
  5. tomclancey

    tomclancey What's a Dremel?

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    Thanks! And I did read that one as a cursory start, but most of the help I've got was from browsing the NUI group forum. http://nuigroup.com/forums

    This specific thread helped me a lot too: http://nuigroup.com/forums/viewthread/5381/P0/

    Thanks! It's pretty close to being done actually. I just have to wait for the IR LED arrays to come in the mail. DealXtreme takes almost 14 days to arrive from initial purchase!

    As for the pictures not showing up, I do host them from home, so that's probably it. I'll move them to imageshack shortly.

    Thanks! I was so excited to start this, especially on my birthday!


    I'll hopefully have some more updates soon, but I'm currently in the midst of another desk project that needs my full attention. Hopefully soon though!
     
  6. PsYcHoTiC_MaDmAn

    PsYcHoTiC_MaDmAn Unholy Cyborg Fruit Machine

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    I came across this as a sensor, though not found a lot of technical details on it (not really looked though)
    (for some reason cant get it to embed youtube, so a link instead
    http://www.youtube.com/watch?v=cq2Ng14dV6E
     
  7. Mosquito

    Mosquito Minimodder

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    That looks pretty interesting, I like the concept :thumb:


     
  8. tomclancey

    tomclancey What's a Dremel?

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    Update! I finally found the time to pickup the parts from my friends house. He's going on vacation and I wanted to get this done while he's away!

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    The holes in the bottom have since been patched. I'm also going to be sealing the corners with some spare MDF. It's going to be one ugly desk, but functional!

    I'm also changing the design to make it more portable. I'm going to cut off the corners of the table top and detach them from each other. Instead they're going to be hinged to the tops of the legs and will swing down to about a 45 degree angle. It'll discourage users from putting their weight on it, plus it'll be much smaller form factor for transportation!

    That, and those angle cuts look awful.
     
    Last edited: 20 Jul 2011
  9. -Jv-

    -Jv- What's a Dremel?

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    Sounds like fun ! Can't see the pics tho. They just don't load.
     
  10. fdbh96

    fdbh96 What's a Dremel?

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    Same :(
     
  11. tomclancey

    tomclancey What's a Dremel?

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    How about now? My Apache server was acting a bit funny.
     
  12. Mosquito

    Mosquito Minimodder

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    pictures work now for me, but it loads extremely slow... and I'm at work, so it shouldn't be internet connection on my end
     
  13. tomclancey

    tomclancey What's a Dremel?

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    Oh it's definitely slow because of me. I'll move them over to imageshack. My home internet is absolute garbage.
     
  14. -Jv-

    -Jv- What's a Dremel?

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    Ahh, pictures loaded for me :) Great work from what I can see.. I've always been intrigued by large touch devices so I'm definitively following this build !
     

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