A vacuum tube computer next to a part of its schematic

This Colossal Vacuum Tube Computer Plays A Mean Game Of Pong

It doesn’t happen often that we report on new vacuum tube based computer designs. Today however, we’re pleased to introduce to you the Fast Reliable Electronic Digital Dot Computer, or Fred.Computer for short. It’s the brainchild of [Mike] who also brought us ENA, which we featured earlier.

Fred is a new design that reuses the parts that made up ENA. It has an 8-bit CPU, 16 bytes of RAM, 256 bytes of NVRAM, and runs at a clock speed of 11.3 kHz. With its 560 tubes drawing a total supply current of about 200 A it also provides a fair bit of heating to [Mike]’s study. The main logic is implemented through NOR gates, built from 6N3P dual-triode tubes sourced from Eastern Europe. These NOR gates are combined into more complex structures like latches, registers and even a complete ALU. A total of sixteen machine code instructions can be used to write programs; clever design allows Fred to perform 16, 32 or even 64-bit calculations with its 8-bit ALU.

A PCB with many reed relays
Need some RAM? There’s sixteen bytes right here.

An interesting addition is a new RAM design based on reed relays. [Mike] realised that relays are actually very similar to digital transmission gates and can therefore be used to make a simple static RAM cell. If you thought relays were too slow for RAM cells, think again: these reed relays can toggle at a mind-boggling 700 Hz, making them more than fast enough for Fred.

The main I/O device is a console that contains several pushbuttons as well as a 12 x 8 LED display. All of this makes Fred a fully-functional general-purpose computer that’s even capable of playing Pong (video, embedded below). [Mike]’s website is full of interesting detail on all aspects of vacuum tube computer design, and makes delightful reading for anyone tempted by the idea of building their own.

Can’t get enough of vacuum tube computers? Have a look at this 1-bit MC14500 implementation, marvel at this modern interpretation of an adding machine, or find out how IBM designed its logic in the 1950s.

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Pong In Hardware… Virtually

We are big fans of the Falstad circuit simulator. Sure, it isn’t perfect, but there’s nothing else like it when you want to whip up a simple circuit. But we were blown away when we saw a more or less complete hardware implementation of Pong in Falstad. No kidding. Starting with the original schematics, there are multiple pages that show each sub-circuit and even a playable subset that you can play the game in your browser.

But wait… you probably noticed there’s no CRT display in the simulator’s component menu. That’s true, there isn’t. However, you can write JavaScript to interact with a running simulation, so the display is a simple bit of JavaScript that samples signals at predetermined points and does the appropriate drawings. There’s even audio output for the sound effects, although that is built into the simulator.

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Old School Mechanical Pong Still Amazes

[Tom], of the YouTube channel ThingsTomLike, found a very sweet little mechanical Pong clone at a thrift store. It came in broken, but in only fifteen minutes of your time, [Tom] manages a complete teardown and repair. (Video, embedded below.)

The game works by balancing a lightbulb on the end of a pivot arm that projects a “ball” onto a screen, while players move their paddles up and down to hit the spring that surrounds the light assembly. The ball arm gets periodically kicked by a DC motor and cam assembly, which makes it careen wildly back and forth across the screen.

It’s a marvel of simple, no-IC engineering. Ironically, it might have been cheaper than making it out of silicon at the time, but viewed from today’s economy, just the human labor in adjusting that counterweight so that the “ball” floats would blow the budget.

Why a screen and lightbulb? Because it’s emulating Pong, a video game, the new kid on the block. But even 45 years later, we think it has got a charm all of its own that the cold digital logic of Pong lacks, even if the gameplay suffers.

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Hackaday Links: February 13, 2022

If you need evidence that our outwardly peaceful little neck of the solar system is actually a dangerous place, look no further than the 40 newly launched Starlink satellites that were just clobbered out of orbit. It seems that the SpaceX launch on February 3 was ill-timed, as it coincided with the arrival of energetic plasma from a solar storm that occurred a few days before. The coronal mass ejection followed an M-class flare on the Sun, which was aimed just right to hit just as the 49-satellite addition to the Starlink constellation was being released. This resulted in an expansion of the upper atmosphere sufficient to increase drag on the newborn satellites — up to 50% more drag than previous launches had encountered. Operators put the satellites into safe mode, but it appears that 40 of them have already met a fiery demise, or soon will. Space is a tough place to make a living.

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Pi Pico Project Plays Pong Perfectly

Even as technology keeps progressing, we find ourselves coming back to the classics again and again. Pong is quite possibly the classic game, and the Raspberry Pi Pico is one of the latest microcontrollers. So [Nick Bild] combined them expertly in his Pico Pong project, which includes gesture controls and a custom VGA output.

Rolling your own VGA signal is no simple feat, and this project takes full advantage of the Pico’s features to pull it off. Display data is buffered in memory, while a Programmable I/O (PIO) program reads straight from the buffer via Direct Memory Access (DMA) and writes straight to the display. This allows for nanosecond-precision while leaving the CPU free to handle inputs and run the game. Even with the display work offloaded, the ARM processor had to be massively overclocked at 258 MHz, well over its 133 MHz specs, to make things run smoothly. And still [Nick] found himself limited to a 640×350 resolution and serendipitously-retro-accurate monochrome color scheme.

Gesture controls come from a pair of IR light beams hooked up to the GPIO. IR LEDs shine up toward reflectors, and the light bounces back down to detectors. Blocking one of the beams causes your paddle to move up or down, which looks pretty responsive in the video (embedded below).

We’ve seen [Nick] play Pong before, though at that time it was handheld and based on the venerable 6502. And just recently we wrote about the Raspberry Pi Pico powering another classic game: Snake.

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Framed PONG Is Picture Perfect

How cool would it have been if arcade cabinets had acrylic panels all along that let you gaze upon the field of TTL chips within? When [Jürgen Müller] scored the innards of an original 1972 PONG machine, that’s exactly what the plan was: build a suitable cabinet that re-imagines PONG as a sleek and stunning work of art.

Instead of trying to cram a CRT in that nice mahogany cabinet, [Jürgen] opted to use an 8″ TFT screen. But get this: [Jürgen] built a Spartan 6 FPGA-based upscaler to adds the scan lines, blur, and afterglow that make it look like the classic PONG experience.

[Jürgen] also built an interface board that amplifies the sound, splits the video out into sync and brightness for the upscaler, and provides 5 V to the PONG circuit board. [Jürgen] decided to circumvent the board’s native voltage regulator in the name of keeping things cool.

[Jürgen] says the project’s web page is in a preliminary stage right now with more information to come. We sure hope that includes a video of it in action. For now, you can check out the files for the interface PCB, the FPGA board, and a list of the fonts.

Should you ever get tired of classic PONG, try playing it in one dimension.

Thanks for the tip, [Anonymous].

Linear Pong Loses A Dimension But Remains Challenging

When Pong hit the scene in the early 70s, there was something about the simplicity of the 2D monochrome tennis game that made it engaging enough that enthusiastic proto-gamers shorted-out machines by stuffing their coin boxes to overflowing.  But even with the simplicity of Pong’s 2D gameplay, the question becomes: could it by made simpler and still be playable?

Surprisingly, if this one-dimensional Pong game is any indication, it actually seems like it can. Where the original Pong made you line up your paddle with the incoming ball, with the main variable being the angle of the carom from your opponent, [mircemk]’s version, limited to a linear game field, makes the ball’s speed the variable. Players take control of the game with a pair of buttons at the far ends of a 60-LED strip of WS2812s. The ball travels back and forth along the strip, bouncing off a player’s paddle only if they push their button at the exact moment the ball arrives. Each reflection back to the opponent occurs at a random speed, making it hard to get into a rhythm. To add some variety, each player has a “Boost” button to put a little spice on their shot, and score is kept by LEDs in the center of the play field. Video of the game play plus build info is below the break.

With just a Neopixel strip, an Arduino Nano, and a small handful of common parts, it should be easy enough to whip up your own copy of this surprisingly engaging game. But if the 2D-version is still more your speed, maybe you should check out the story of its inventor, [Ted Dabney]. Or, perhaps building a clock that plays Pong with itself to idle the days away is more your speed.

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