Unique Flat-Screen Display Put To Use In CRT Game Boy

The cathode-ray tube ruled the display world from the earliest days of TV until only comparatively recently, when flat-screen technology began to take over. CRTs just kept getting bigger over that time until they reached a limit beyond which the tubes got just too bulky to be practical.

But there was action at the low end of the CRT market, too. Tiny CRTs popped up in all sorts of products, from camcorders to the famous Sony Watchman. One nifty CRT from this group, a flat(tish) tube from a video intercom system, ended up in [bitluni]’s lab, where he’s in the process of turning it into a retro Game Boy clone with a CRT display. The display, which once showed the video from a door-mounted camera, was a gift from a viewer. Date codes on the display show it’s a surprisingly recent device; were monochrome TFT displays that hard to come by in 2007? Regardless, it’s a neat design, with the electron gun shooting upward toward a curved phosphor screen. With a little Google-assisted reverse engineering, [Bitluni] was able to track done the video connections needed to use his retro game console, which uses an ESP32 that outputs composite video. He harvested the intercom speaker for game audio, added a temporary Nintendo gamepad, and soon he was playing Tetris in glorious monochrome on the flat screen.

The video below is only the first in a series where the prototype will be stuffed into one nice tidy package. It certainly still needs some tweaking, but it’s off to a great start. We can’t wait to see the finished product.

[baldpower] tipped us off to this one. Thanks again!

30 thoughts on “Unique Flat-Screen Display Put To Use In CRT Game Boy

    1. There’s a difficult-to-place appeal to cassette futurism . Probably just because I personally grew up surrounded by them, but nothing quite replaces the glow of a CRT. The glassy noises it makes when it’s warming up. The crackly field of static an inch away from its surface. The subtle flicker and sweep of the image.

      I love finding an excuse to use one in a project. All those imperfections create a character that just can’t be replicated with a TFT or whatnot.

    1. Wpw, that’s a clever setup for a side-firing electron gun. The rectangular glass envelope with some leads coming off the side like a gigantic DIP kind of reminds me of those old VFDs for displaying the status of a cassette deck or whatnot.

      1. These side firing CRTs were quite popular for handheld TVs in the 80’s/early 90’s until LCD prices became competitive. The CRT in the sinclar is slightly different though, it uses electrostatic defection, so it is more like an old school analog scope tube than a classic TV boob tube. AFAIK the tube in the sinclair is the only “flat crt” that is electrostatic like this. The tube shown in this video and that were quite popular in handheld Sony B/W watchman TVs used magnetic deflection, just like in a standard CRT TV.

        1. Haha yes the old “Church Skipper” lol. We were always late due to Lost in Space airing just before church. I had a Sony with side firing crt for a while. Never used it as much as I thought I would.

  1. The product was most likely designed at least 1-2 years prior to the manufacturing date on the CRT. A quality color 3.5″ TFT mosule cost $90+ in 2005. It’s not too hard to believe that this CRT with decent manufacturing volume behind it could have been mostly chosen due to its lower cost than for technical reasons.

    1. My mother had a pocket television with a colour LCD screen in the mid-late 90s. The whole thing cost her less than 100 GBP at the time. I would sometimes borrow it when I went with my father to his workplace on a Saturday morning. This was also when I learned how to play minesweeper!

  2. I’ve got exactly the same unit lying around from a door intercom.
    Apparently the (I believe Italian) company that built those things kept churning them out whilst TFT monitors where abundantly available. Apartment buildings in the Netherlands (and assumingly the rest of Europe) are filled with these things.

  3. I’ve wanted to do similar myself. Managed to get one of the smaller Watchman screens (not the smallest, I think the next one down from these) and…. yeah. Trying to get one of this size at a decent price is proving difficult.

    1. The reason oscilloscopes (vector displays) used electrostatic deflection instead of magnetic deflection was the ability to drive the deflection with (almost) any frequency you liked, whereas coils are quite sensitive to the frequency they are driven at.
      For TV’s it was cheaper (and resulted in shorter tubes) because the H and V frequencies are alaways the same.

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