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Thread: CYGN-B

  1. #671
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    Mar 2010
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    Ah, I see it in the docs now. Thanks.

  2. #672
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    Mar 2010
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    This is the update where we see four channels with joysticking. Tweaking needs be obviously, but it is working. The jitteriness of the images is entirely due to the joystick, and will go away with code for damping.

    video here:
    https://www.youtube.com/watch?v=XVrhhtzZA4E

    Suggestions open for an algorithm to effect variable damping. I'm thinking change xy to polar and compare magnitudes to threshold an accept new sample. This isn't like variable damping though.

    Quote Originally Posted by lasermaster1977 View Post
    Are you or have you thought of using selectable degrees of RC damping on the joystick XY axes? I always preferred and only ever used non-centering joysticks with switch selectable degrees of damping from none to a lot, but I never thought of using a circular mask. What a neat idea!
    Attached Thumbnails Attached Thumbnails multabela_first_light.jpg  

    card_cage4.jpg  

    bela_bay.jpg  


  3. #673
    Join Date
    Sep 2014
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    Colorado USA
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    793

    Default Great progress, Greg!

    Its coming together nicely. Your efforts are to be heartily congratulated!

    Seems like you could use a quad or octal, dual-channel analog multiplexer CMOS switch that uses 2 or 4 bits to select the the desired 1 of 4 or 1 or 8 pair of low-pass filter caps across the buffered joystick XY outputs. The switched cap values could be in an integrator opamp feedback loop with a 10K or 50K or 100K input resistor on the inverting input, with the non-inverting input grounded. Admittedly, this method is more component intensive and requires only a very few available binary outputs for low-pass filter behavior selection whereas a software solution requires more processing bandwidth and code lines.
    ________________________________
    Everything depends on everything else

  4. #674
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    Feb 2015
    Location
    San Francisco
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    184

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    Greg,

    Your wiring is sheer artistry (in a Jackson Pollack sort of way!). Forget about the lasers. I'd put your wire harnesses (that's a very generous use of the word "harness"...) into an art gallery themselves!

    Ron

    PS. Any high resolution shots you can send of your Osmium would be great. Especially if it was against a dark background I could extract it from (you may have noticed my backgroundless use of imagery in my Keynotes - I take great pains to make them as clean as possible.) Also if you had a few different angles, assuming it is not a sphere! Thanks for the offer! It may be a while before I get to Osmium as I may be starting all over again at Hydrogen because I'm probably doing these live at Chabot Space and Science Center in Oakland and I thought it unfair if I started way up in the Lanthanides. How big is your sample? Must be sizable compared to every other BB-sized sample of Osmium I've ever seen.



    Quote Originally Posted by Greg View Post
    This is the update where we see four channels with joysticking. Tweaking needs be obviously, but it is working. The jitteriness of the images is entirely due to the joystick, and will go away with code for damping.

    video here:
    https://www.youtube.com/watch?v=XVrhhtzZA4E

    Suggestions open for an algorithm to effect variable damping. I'm thinking change xy to polar and compare magnitudes to threshold an accept new sample. This isn't like variable damping though.

  5. #675
    Join Date
    Jun 2009
    Location
    St. Louis, MO
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    1,199

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    I wish I was clever enough to come up with the Jackson Pollack comparison!

    Greg I thought I sent some reverse log 1 meg dual pots there's a Laserium low pass filter circuit for the joysticks...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  6. #676
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    Mar 2010
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    Looking through the schematics. Couple of interesting ones. One is 6b-NOGN.pdf which is a noise generator? I don't see anything in the data frame that indicates access of such a board.

    Other one is 6b-BTBX.pdf which is 351 frame generator assembly also called bit box. My file is missing page 5 due to file corruption. Perhaps someone with this file could test theirs and see if they have this file with the missing page.

    About the last component to test in the process of bringing the multabela system up and playing content is an inspection of the chopper and colormod signals as they are received by the belas. Boring screen capture of software oscilloscope in future post.

    The trim pots were successfully adjusted to bring Ivan's space politely just within the projector limits. Grats to those who suggested accessible placement.

    Quote Originally Posted by TheHermit View Post
    For variable software damping, I was thinking of simply averaging a 'n' number of streaming joystick offsets.
    Good tip, Roger, is it? I'll do it, thanks.

    I unfortunately took apart the slow drive carousel with micro positioner camera mount and made the joystick with circular mask out of it, shortly before i knew that osmium pics could be useful. These pics are ok but I was holding the camera so everything has some motion crap. I'll see what I can do to get better results as time permits. Photos include the reflection of a gold coin in osmium, and one in which osmium's blue fire is seen.

    Perhaps Jackson Pollack style wiring is a sub-discipline of open air flying architecture. Indeed harness is orders of magnitude too generous a term to throw at this wiring. Only the belas are harnessed here.
    Attached Thumbnails Attached Thumbnails multabela_tests_1.jpg  

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    osmium.jpg  

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    osmium_blue_fire.jpg  

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  7. #677
    Join Date
    Jun 2009
    Location
    St. Louis, MO
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    The noise generators were mounted near the scanners in the optical head. When the x/y signal dropped below a threshold they switched on and injected a noise signal to each axis - it made a fade into the distance effect difficult to impossible.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  8. #678
    Join Date
    Feb 2015
    Location
    San Francisco
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    Greg,

    I believe, if memory serves me, that the NOGN card was somewhere in the lower cage. It was an annoyance and I never had it installed. It was a nod to BRH (now CDRH) for stupid methods to make the class 4 laser "safe".

    The bitbox was a very useful tool to set up static 6b frames of data. Useless during a show, but great for troubleshooting.

    On the Osmium photo, could you provide one of the entire blob of Osmium without any cropping of the object? Your black background looks fantastic!

    Ron



    Quote Originally Posted by Greg View Post
    Looking through the schematics. Couple of interesting ones. One is 6b-NOGN.pdf which is a noise generator? I don't see anything in the data frame that indicates access of such a board.

    Other one is 6b-BTBX.pdf which is 351 frame generator assembly also called bit box. My file is missing page 5 due to file corruption. Perhaps someone with this file could test theirs and see if they have this file with the missing page.

    About the last component to test in the process of bringing the multabela system up and playing content is an inspection of the chopper and colormod signals as they are received by the belas. Boring screen capture of software oscilloscope in future post.

    The trim pots were successfully adjusted to bring Ivan's space politely just within the projector limits. Grats to those who suggested accessible placement.


    Good tip, Roger, is it? I'll do it, thanks.

    I unfortunately took apart the slow drive carousel with micro positioner camera mount and made the joystick with circular mask out of it, shortly before i knew that osmium pics could be useful. These pics are ok but I was holding the camera so everything has some motion crap. I'll see what I can do to get better results as time permits. Photos include the reflection of a gold coin in osmium, and one in which osmium's blue fire is seen.

    Perhaps Jackson Pollack style wiring is a sub-discipline of open air flying architecture. Indeed harness is orders of magnitude too generous a term to throw at this wiring. Only the belas are harnessed here.

  9. #679
    Join Date
    Jun 2009
    Location
    St. Louis, MO
    Posts
    1,199

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    No, if it was in the lower cage it would have been overridden when the select switches were in the down (red) position. In the machine I had at the Smithsonian they were up near the scanners on the optical head. I don't believe we ever had them in St. Louis either. Carl Hannigan joked once about when someone "tests" your projector by holding up a piece of white paper that you should ask where they get their business cards calibrated...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  10. #680
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    Mar 2010
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    Here's the boring software oscilloscope capture previously promised. Shown are the four signals generated by the 6b rebuild that all the belas receive. Four joystick signals not shown. Everything looks good. There's the side pod from the 6b panel received from Brian. It has been repurposed, for now at least, as the the panel for the 8 controls for chopper and colormod. These signals come from duplicates of the CYGN ramp generator circuit (the breadboard strip in front.) Each of the two oscillators has a control for frequency, shape, gain, and offset. The offset parameter on the intensity (chopper) function allows the master fader to still be the master fader. Unfortunately, the output of diode based projectors becomes non linear at low intensities.

    Wow that noise board sounds like a most unwelcome feature.

    Brian, yes I have the joystick hardware you sent, but I don't have a disk to mount a shaft onto the potentiometer. Also, I looked through the schematics that have J in the file name, but I didn't see (or I missed) documentation for the low pass filter circuit board.
    Attached Thumbnails Attached Thumbnails multabela_tests_5.jpg  

    signals_6.png  


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