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All About CRTs

26 Junio 2024 at 05:00

For old-timers, CRTs — cathode ray tubes — were fixtures as kids sat in front of TVs watching everything from Howdy Doody to Star Trek. But there’s at least one generation that thinks TVs and computer monitors are flat. If that describes you, you might enjoy [The 8-Bit Guy’s] coverage of how CRTs work in the video below.

CRTs were heavy, took high voltage, and had a dangerous vacuum inside, so we really don’t miss them. The phosphor on the screen had a tendency to “burn in” if you showed the same image over and over. We don’t miss that either.

The basic idea is simple. An electron is fired at the phosphor behind the screen. An electrostatic or electromagnetic arrangement allows you to hit specific spots on the screen, and, of course, you can turn the beam off. Color CRTs have three different phosphors, and the beams have to fire at the correct color phosphor.

The best part of the video is the part where they tear apart an actual CRT, something you don’t see very often. We were worried about the vacuum, but the tube in question had already vented to atmosphere.

We doubt CRTs will make a comeback like vinyl records have. If so, maybe you’ll settle for a software simulation. It does make retrocomputing simulators feel better.

Tight Handheld CRT Asteroids Game Curses in Tuscan

12 Junio 2024 at 20:00

How many Arduini does it take to make a tiny CRT Asteroids game? [Marco Vallegi] of MVV Blog’s answer: two. One for the game mechanics and one for the sound effects. And the result is a sweet little retro arcade machine packed tightly into a very nicely 3D printed case.

If you want to learn to curse like a Tuscan sailor, you can watch the two-part video series, embedded below, in its entirety. Otherwise, we have excerpted the good stuff out of the second video for you.

For instance, we love the old-school voice synthesis sound of the Speak and Spell. Here, playback is implemented using the Talkie library for Arduino, and [Marco] is using the BlueWizard software on a dated Macbook for recording and encoding. (We’d use the more portable Python Wizard ourselves.) Check out [Marco] tweaking the noise parameters here to get a good recording.

And since the Talkie Arduino library uses PWM on a digital output pin to create the audio, the high-frequency noise was freaking out his simple transistor amplifier. Here, [Marco] adds a feedback capacitor to cancel that high-frequency hash out.

The build needs to be quite compact, and the stacked-Arduino-with-PCB-case design is tight. And the 3D-printed case has a number of nice refinements that you might like. We especially like the use of thin veneers that cover the case all around with the build-plate’s surface texture, and the contrasting “Asteroids” logos are very nice.

All in all, this is a really fun build that’s also full of little details that might help you with your own projects. Heck, even if it just encourages you to play around with the Talkie library, it’s worth your time in our opinion. And while you’re at it, you can turn on the subtitles and pick up some vocab that’ll make your nonna roll over in her grave.

Part One: Rebuilding the CRT

Part Two: Adding Sound

Thanks [ZioTibia81] for the tip!

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