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Narrow Bandwidth Computer Terminal project

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  • Joe Giliberti
    I ve come up, at this point, with a (semi) realistic VCF plan. It involves constructing an electromechanical video display, such as those used in television
    Message 1 of 4 , May 26, 2008
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      I've come up, at this point, with a (semi) realistic VCF plan. It involves constructing an electromechanical video display, such as those used in television research in the 1920's and 1930s, and somehow, using it as a display terminal for a computer.

      As narrow bandwidth TV works, it uses an audio signal to flash a light, which shines through the holes around the circumference of a Nipkow disk. As the disk spins faster and faster, at around 750 RPM for a 32 hole disk, the lines sync up, and you get a picture, usually maginified by a lense, like one from a viewgraph projector.

      The trick is, I have no idea on how to convert, lets say, a composite video output, to the light flashes of an LED behind the disk. How would one go about doing this?

      Joe
    • Ray Sills
      HI Joe: The main issue is going to be synchronization. The mechanical TV system used spinning disks at the camera, and another at the receiver. Early
      Message 2 of 4 , May 26, 2008
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        HI Joe:

        The main issue is going to be synchronization. The mechanical TV
        system used spinning disks at the camera, and another at the receiver.
        Early receivers had a knob to adjust the disk motor's speed. Once
        the receiver's disk was spinning at the same speed as the camera's, then
        you'd have a good "non-drifting" image.

        Today's TV and video monitor scan speeds are so much faster, that you
        would probably have to spin the disk at a very high rate, or use some
        sort of electronic system to make the mechanical disk spin at some
        whole number fraction of the scan rate.

        32 lines of resolution is a pretty crude video picture.

        73 de Ray


        On May 26, 2008, at 7:10 PM, Joe Giliberti wrote:

        > I've come up, at this point, with a (semi) realistic VCF plan. It
        > involves constructing an electromechanical video display, such as
        > those used in television research in the 1920's and 1930s, and
        > somehow, using it as a display terminal for a computer.
        >
        > As narrow bandwidth TV works, it uses an audio signal to flash a
        > light, which shines through the holes around the circumference of a
        > Nipkow disk. As the disk spins faster and faster, at around 750 RPM
        > for a 32 hole disk, the lines sync up, and you get a picture,
        > usually maginified by a lense, like one from a viewgraph projector.
        >
        > The trick is, I have no idea on how to convert, lets say, a
        > composite video output, to the light flashes of an LED behind the
        > disk. How would one go about doing this?
        >
        > Joe
        >
      • Mike Loewen
        A couple of months back, there was a thread about EPROM programmers suitable for classic systems. While the Willem programmer was one of the recommended
        Message 3 of 4 , May 28, 2008
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          A couple of months back, there was a thread about EPROM programmers
          suitable for classic systems. While the Willem programmer was one of the
          recommended models, I wasn't too keen on the USB requirement. Another
          recommendation was the Data I/O 29B, a standalone unit which can be
          connected via RS-232 port to a system or terminal. I started keeping an
          eye on the Ebay offerings, and finally picked up one at a reasonable
          price:

          http://sturgeon.css.psu.edu/~mloewen/DataIO/

          It came with the following adapters:

          Unipak 2B
          LogicPak
          303A-011 V01
          303A-011 CMOS/BiPolar
          910-1521 Calibration Extender
          351B-086

          If I'm reading things right, I have the right adapters to do 2764s and
          the like. I'm anxious to see if I can program a TurboROM or a KayPLUS ROM
          for my Kaypro 10. :-)


          Mike Loewen mloewen@...
          Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
        • Bob Applegate
          The 29 is a great programmer. Used them at many jobs in the 80s. I don t remember the adaptor model numbers, but the 29 could program just about anything
          Message 4 of 4 , May 28, 2008
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            The 29 is a great programmer.  Used them at many jobs in the 80s.  I don't remember
            the adaptor model numbers, but the 29 could program just about anything with the
            right adaptor.  I was usually doing 2708s, 2716s, and 2732s.

            You got yourself a good piece of equipment.

            Speaking of which, it's time to head into the basement and burn a new EPROM for
            my S-100 machine...

            Bob


            On May 28, 2008, at 6:58 PM, Mike Loewen wrote:


            A couple of months back, there was a thread about EPROM programmers 
            suitable for classic systems. While the Willem programmer was one of the 
            recommended models, I wasn't too keen on the USB requirement. Another 
            recommendation was the Data I/O 29B, a standalone unit which can be 
            connected via RS-232 port to a system or terminal. I started keeping an 
            eye on the Ebay offerings, and finally picked up one at a reasonable 
            price:

            http://sturgeon. css.psu.edu/ ~mloewen/ DataIO/

            It came with the following adapters:

            Unipak 2B
            LogicPak
            303A-011 V01
            303A-011 CMOS/BiPolar
            910-1521 Calibration Extender
            351B-086

            If I'm reading things right, I have the right adapters to do 2764s and 
            the like. I'm anxious to see if I can program a TurboROM or a KayPLUS ROM 
            for my Kaypro 10. :-)

            Mike Loewen mloewen@cpumagic. scol.pa.us
            Old Technology http://sturgeon. css.psu.edu/ ~mloewen/ Oldtech/


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