More CRT fun with the Scope Clock

That’s a sexy way to use parts from an old oscilloscope. [Aaron] took his inspiration from another project that was using CRTs from old oscilloscopes. Now he’s giving back with a site dedicated to sharing information about the Scope Clock. This project is along the same lines as the one we saw a few days ago.

The image above shows his first build in its new home in Hong Kong. The clock is housed in two clear acrylic containers, paired through a surprisingly beefy military grade connector. You can see the journey that it took to get to this polished finish by going to the Prototype tab at the top of the page linked above. One of the images shows some fast captures of the screen redraw. It lets you see the vectors which are being traced on the phosphor screen by the electron gun. This gives an image that we think is far more pleasing than the row scanning of a traditional CRT monitor.

Of course you don’t have a to start from scratch either. Here’s a clock project that just augments a functional CRT scope.

Comments

  1. svofski says:

    New to me, great project! I agree with the author that peeking from behind the screen is one of the most fascinating things ever.

  2. I really like this hack, but being old enough to remember CRT burn-in – let’s take it a step further…
    A stepper drivem caddy to ‘roll’ the CRT every second/minute – through a range (perhaps 10 to 350 degrees in small steps. Probably limited by the physical connections to the tube.)

    Then rotate the displayed content in the opposite direction so that is perceived as ‘static’ on the continually displaced display screen.

    The result will be a far greater tube life, and a very cool gadget to watch.

  3. p.s. nice view!

  4. macona says:

    Oh, I want to build one. But the board prices may be a killer.

  5. echodelta says:

    Other than the burn-in problem, elegant! 24 hour time is a plus. Add both and count down to hour, slew more by, to randomize.

  6. chango says:

    It’s hard to tell from the photos, but it looks like he’s using CPC connector shells without the connector installed. Makes sense since he needs to pass HV to the tube over that wiring and I’m not sure there is a CPC insert that could accommodate that.

  7. HackerK says:

    That’s HK in the background.. wonder if that’s an office or condo view..

  8. bothersaidpooh says:

    Has anyone used a flat CRT for
    something like this? With modern
    micros it should be simple to
    compensate for the non linear scan
    field and angle of the view plate.
    You simply bias the H coil with
    DC wrt ground to make it work.

  9. ys0 says:

    what font is it?

    • Greenaum says:

      A home-made, proportional one, based on circles, segments (or is it sectors?) of circles, and straight lines. Largely based on modified lissajous figures.

      An analogue circle generator (ie 2 sine waves offset from each other) draws all the rounded parts, giving genuine curves, not approximated from straight lines. The original designer of the clock goes into detail about this on his “theory of operation” page,

      http://www.cathodecorner.com/sc200theory.html

      It’s very elegant and attractive, the ideas he’s used in it, not sure if a CRT has ever used such a method of generating characters before. The latest model apparently has a full ASCII character set.

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