Exploring The Gakken FX Micro-Computer

November 18, 2024 by 9 Comments

Early computer kits aimed at learning took all sorts of forms, from full-fledged computer kits like the Altair 8800 to the ready-made MicroBee Computer-In-A-Book. For those just wanting to dip their toes in the computing world, many low-cost computer “trainers” were released, and Japan had some awesome ones. [Jason Jacques] shows off his Gakken Micro-Computer FX-System (or is it the FX-Computer? Or maybe the FX-Micom? It seems like they couldn’t make up their minds). In any event, it was a combination microcomputer and I/O building blocks system running a custom version of the Texas Instrument TMS1100 microprocessor. Specifically designed to introduce users to the world of computing, the included guide is very detailed and includes 100 example programs and lots of information on how all the opcodes work.

This 4-bit system is similar to the Kenbak computer, with a very simple instruction set and limited address space. However, adding electronic components in plastic blocks brings this machine to a new level of interactivity. Connections can be made to and from the microcomputer block, as well as to the on-board speaker and simple input/output pins.  The example circuit displayed on the front cover of the box enables the microcontroller to connect to the speaker and allows a switch to light up a small incandescent bulb. We can imagine many users wiring up all sorts of extra components to their FX-Computers, and with the advent of 3D printing, it wouldn’t be difficult to create new blocks to insert into the grid.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Typo

November 18, 2024 by 13 Comments

Ceci n’est pas une keyboard, sure. But it’s keyboard-adjacent, and how. [Joshua Bemenderfer]’s wrists are tired of moving off the keyboard in order to mouse, and he decided to create a trackball that can sit just below the Space bar. The idea is to get rid of the regular mouse entirely if this works out.

A split keyboard with a DIY trackball beneath the Space bar.
Image by [Joshua Bemenderfer] via Hackaday.IO
And sure, the Ploopy family of open-source mice would welcome him with open arms, but they don’t come cheap. [Joshua]’s plan here is to make something for under $10. Ideally, less than $5.

Starting with an off-the-shelf trackball, the first BOM came in around $25 if you throw in $5 for the 3D printing of the case. [Joshua] added some cheap ceramic bearings to make it better. Since this was still too high, he turned to the internals of cheap mice.

Trial and error has resulted in a 99-cent special from Ali being the idea candidate. There are even cheaper mice to be had, but this one has an ideal layout for doing a bit of surgery. It also requires remapping since [Joshua] is flipping the sensor upside down and using a POM ball on top of it. Now he just needs to figure out how to add buttons and make them split keyboard-friendly.

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The Laser Shadow Knows

November 18, 2024 by 31 Comments

Normally, you think of things casting a shadow as being opaque. However, new research shows that under certain conditions, a laser beam can cast a shadow. This may sound like nothing more than a novelty, but it may have applications in using one laser beam to control another. If you want more details, you can read the actual paper online.

Typically, light passes through light without having an effect. But using a ruby crystal and specific laser wavelengths. In particular, a green laser has a non-linear response in the crystal that causes a shadow in  a blue laser passing through the same crystal.

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Ruined 1993 ThinkPad Tablet Brought Back From The Brink

November 18, 2024 by 10 Comments

Collecting retrocomputers is fun, especially when you find fully-functional examples that you can plug in, switch on, and start playing with. Meanwhile, others prefer to find the damaged examples and nurse them back to health. [polymatt] can count himself in that category, as evidenced by his heroic rescue of an 1993 IBM ThinkPad Tablet.

The tablet came to [polymatt] in truly awful condition. Having been dropped at least once, the LCD screen was cracked, the case battered, and all the plastics were very much the worse for wear. Many of us would consider it too far gone, especially considering that replacement parts for such an item are virtually unobtainable. And yet, [polymatt] took on the challenge nonetheless.

Despite its condition, there were some signs of life in the machine. The pen-based touch display seemed to respond to the pen itself, and the backlight sort of worked, too. Still, with the LCD so badly damaged, it had to be replaced. Boggling the mind, [polymatt] was actually able to find a 9.4″ dual-scan monochrome LCD that was close enough to sort-of fit, size-wise. To make it work, though, it needed a completely custom mount to fit with the original case and electromagnetic digitizes sheet. From there, there was plenty more to do—recapping, recabling, fixing the batteries, and repairing the enclosure including a fresh set of nice decals.

The fact is, 1993 IBM ThinkPad Tablets just don’t come along every day. These rare specimens are absolutely worth this sort of heroic restoration effort if you do happen to score one on the retro market. Video after the break.

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Analog Shift Register Revealed

November 17, 2024 by 18 Comments

Nowadays, if you want to delay an audio signal for, say, an echo or a reverb, you’d probably just do it digitally. But it wasn’t long ago that wasn’t a realistic option. Some devices used mechanical means, but there were also ICs like the TCA350 “bucket brigade” device that [10maurycy10] shows us in a recent post.

In this case, bucket brigade is a euphemism calling to mind how firemen would pass buckets down the line to put out a fire. It’s a bit of an analog analogy. The “bucket” is a MOSFET and capacitor. The “water” is electrical charge stored in the cap.  All those charges are tiny snippets of an analog signal.

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Completing The UE1’s Paper Tape Reader And First Squiggles

November 17, 2024 by 1 Comment
The UE1 tape reader in its nearly finished glory. Note the resistor to regulate the motor speed. (Credit: David Lovett, Usage Electric)
The UE1 tape reader in its nearly finished glory. Note the resistor to regulate the motor speed. (Credit: David Lovett, Usagi Electric)

On today’s installment of UE1 vacuum tube computer construction, we join [David Lovett] once more on the Usagi Electric farm, as he determines just how much work remains before the project can be called done. When we last left off, the paper tape reader had been motorized, with the paper tape being pulled through smoothly in front of the photodiodes. This left [David] with the task to create a PCB to wire up these photodiodes, put an amplification circuit together (with tubes, of course) to amplify the signal from said photodiodes, and add some lighting (two 1-watt incandescents) to shine through the paper tape holes. All of this is now in place, but does it work?

The answer here is a definite kinda, as although there are definitely lovely squiggles on the oscilloscope, bit 0 turns out to be missing in action. This shouldn’t have come as a major surprise, as one of the problems that Bendix engineers dealt with back in the 1950s was effectively the same one: they, too, use the 9th hole on the 8-bit tape as a clock signal, but with this whole being much smaller than the other holes, this means not enough light passes through to activate the photodiode.

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Hackaday Links: November 17, 2024

November 17, 2024 by 18 Comments

A couple of weeks back, we covered an interesting method for prototyping PCBs using a modified CNC mill to 3D print solder onto a blank FR4 substrate. The video showing this process generated a lot of interest and no fewer than 20 tips to the Hackaday tips line, which continued to come in dribs and drabs this week. In a world where low-cost, fast-turn PCB fabs exist, the amount of effort that went into this method makes little sense, and readers certainly made that known in the comments section. Given that the blokes who pulled this off are gearheads with no hobby electronics background, it kind of made their approach a little more understandable, but it still left a ton of practical questions about how they pulled it off. And now a new video from the aptly named Bad Obsession Motorsports attempts to explain what went on behind the scenes.

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