Fixing An HP 54542C With An FPGA And VGA Display

January 13, 2023 by Maya Posch 11 Comments

Although the HP 54542C oscilloscope and its siblings are getting on in years, they’re still very useful today. Unfortunately, as some of the first oscilloscopes to switch from a CRT display to an LCD they are starting to suffer from degradation. This has led to otherwise perfectly functional examples being discarded or sold for cheap, when all they need is just an LCD swap. This is what happened to [Alexander Huemer] with an eBay-bought 54542C.

Although this was supposed to be a fully working unit, upon receiving it, the display just showed a bright white instead of the more oscilloscope-like picture. A short while later [Alexander] was left with a refund, an apology from the seller and an HP 54542C scope with a very dead LCD. This was when he stumbled over a similar repair by [Adil Malik], right here on Hackaday. The fix? Replace the LCD with an FPGA and VGA-input capable LCD.

While this may seem counter intuitive, the problem with LCD replacements is the lack of standardization. Finding an 8″, 640×480, 60 Hz color LCD with a compatible interface as the one found in this HP scope usually gets you salvaged LCDs from HP scopes, which as [Alexander] discovered can run up to $350 and beyond for second-hand ones. But it turns out that similar 8″ LCDs are found everywhere for use as portable displays, all they need is a VGA input.

Taking [Adil]’s project as the inspiration, [Alexander] used an UPduino v3.1 with ICE40UP5K FPGA as the core LCD-to-VGA translation component, creating a custom PCB for the voltage level translations and connectors. One cool aspect of the whole system is that it is fully reversible, with all of the original wiring on the scope and new LCD side left intact. One niggle was that the scope’s image was upside-down, but this was fixed by putting the new LCD upside-down as well.

After swapping the original cooling fan with a better one, this old HP 545452C is now [Alexander]’s daily scope.

Maxing Out Your MacIntosh With A 4 MB Memory Stick Kit

January 12, 2023 by Maya Posch 22 Comments

One fun aspect of retrocomputing is that you get to max out all aspects of these systems without having to take out a bank loan, as tended to be the case when these systems were new. Less fun is that decades after systems like the Apple MacIntosh SE/30 were last sold, the 30-pin SIMMs that form the expandable RAM for these systems has become rather scarce. This has led many to make their own SIMM PCBs, including [Kay Koba] with a PCB for 4 MB SIMMs along with information on which memory and parity ICs are suitable for these SIMMs.

For systems like the MacIntosh SE/30 with 8 30-pin memory slots, the maximum capacity is 128 MB, but this comes with many gotchas due to its ROM being ’32-bit dirty’. While this can be circumvented by swapping in a ROM from a later MacIntosh variant, the less invasive way is to enable the MODE32 system extension and install eight 4 MB SIMMs for a total of 32 MB RAM. RAM chips for such 30-pin SIMMs can be scavenged from the far more common 72-pin SIMMs, along with any old new stock one may come across.

These 4 MB SIMM PCBs are offered for sale by [Kay] with optionally the SMD components (capacitors, resistors and LED) included in the package. The original PCB card edge design is credited to work by [Zane Kaminski] whose GitHub profile also leads to e.g. this 30-pin SIMM project.

Have you modded your MacIntosh or other retro system yet to the maximum RAM and storage limits?

Building A Homemade Ambient Pressure Submarine

January 11, 2023 by Maya Posch 27 Comments

About two years ago, [Hyperspace Pirate] set to work on building his own two-seater submarine, because who doesn’t want to have a submarine when you have just moved to Florida? In the linked video (also attached below), he describes the reasoning behind the submarine design. Rather than going with a fully sealed submarine with ambient pressure inside and a hull that resists the crushing forces from the water, he opted to go for a semi-wet ambient pressure design.

What this essentially entails is a fancy equivalent of an old-school diving bell: much as the name suggests, these are sealed except for the bottom, which allows for water to enter and thus equalize the pressure. Although this has the distinct disadvantage of being not dry inside (hence the semi-wet), it does mean that going for a dive is as easy as letting the water in via the bottom hole, and to resurface only a small amount of air injected into two ballast tanks and a pump are all that are required.

So far this submarine has survived a few test runs, which uncovered a number of issues, but diving and resurfacing seems to be going pretty smoothly now, which is definitely a massive plus with a submarine.

(Thanks to [Drew] for the tip!)

Continue reading “Building A Homemade Ambient Pressure Submarine” →

The Intricacies Of Creating Fuel For Nuclear Reactors

January 10, 2023 by Maya Posch 51 Comments

All nuclear fission power reactors run on fuel containing uranium and other isotopes, but fueling a nuclear reactor is a lot more complicated than driving up to them with a dump truck filled with uranium ore and filling ‘er up. Although nuclear fission is simple enough that it can occur without human intervention as happened for example at the Oklo natural fission reactors, within a commercial reactor the goal is to create a nuclear chain reaction that targets a high burn-up (fission rate), with an as constant as possible release of energy.

Each different fission reactor design makes a number of assumptions about the fuel rods that are inserted into it. These assumptions can be about the enrichment ratio of the fissile isotopes like U-235, the density of individual fuel pellets, the spacing between the fuel rods containing these pellets, the configuration of said fuel rods along with any control, moderator and other elements. and so on.

Today’s light water reactors, heavy water reactors, fast neutron reactors, high temperature reactors and kin all have their own fuel preferences as a result, with high-assay low-enriched (HALEU) fuel being the new hot thing for new reactor designs. Let’s take a look at what goes into these fuel recipes.

Continue reading “The Intricacies Of Creating Fuel For Nuclear Reactors” →

Building A Giant Remote Controlled Model Airbus A380 In A Year

January 8, 2023 by Maya Posch 21 Comments

A year ago [Ramy RC] set out on a momentous challenge: to build a 1:21 scale Airbus A380-800 RC model with functional engines, landing gear and all other details. Recently he finished the project and published a video with a summary of the whole build process (also linked below). The full video series can be found on the Ramy RC channel. The final RC airplane came out at a massive wingspan of 3.9 meters (12.7′), a length of 3.6 meters (11.8′) and a weight of 25 kg. This weight is carried by the full landing gear of multiple bogeys that can retract much like on the real airplane.

A range of materials were used for the body, including carbon fiber and wood, with each part carefully modeled with CAD software and 3D-printed or cut on a CNC cutter. Four ducted fans provide the propulsive power that lift this enormous model airplane into the skies, which is the only part where the noise profile doesn’t quite match that of the real A380. Even so, seeing the airplane taxing, taking off and flying through the skies makes you look twice to realize that it is in fact a scale model and not a real Emirates A380-800, also courtesy of the excruciating amount of detail to the model’s final look, down from the logos to the silver-grey lines.

We’re also quite convinced that the maiden flight of such an exquisite model has to be one of the most terrifying experiences imaginable.

Continue reading “Building A Giant Remote Controlled Model Airbus A380 In A Year” →

The GitHub Silverware Drawer Dilemma, Or: Finding Active Repository Forks

January 8, 2023 by Maya Posch 11 Comments

An fortunate reality of GitHub and similar sites is that projects that are abandoned by the maintainer are often continued by someone else who forked the project. Unfortunately, the ease of forking also means that GitHub projects tend to have a lot of forks, with the popular projects having hundreds of them. Since GitHub has elected to not provide a way to filter or sort these forks, finding the most active fork can be rather harrowing.

In addition, a popular project’s dead repository tends to score higher in search results than replacement forks. For these particular situations a couple of very useful websites and browser add-ons have been developed. The Lovely Forks add-on by [Utkarsh Upadhyay] seeks to insert information on forks that are notable or newer than the repository one is looking at.

Meanwhile, the Active Forks project by [Samar Dhwoj Acharya] provides a sortable list of project forks when provided with a GitHub repository name. This helps enormously when trying to find the freshest forks in a whole list. This is similar to the Useful Forks project that provides a web-based interface in addition to a Chrome extension. Do note that these queries will count towards the GitHub API rate-limits, so you may need to add an access token.

It’s a shame that GitHub doesn’t offer such functionality by default, but thanks to these projects the times of clicking through a hundred forks to find the freshest one is at least over. For now.

Tiny Robots That Bring Targeted Drug Delivery And Treatment A Little Bit Closer

January 7, 2023 by Maya Posch 8 Comments

Within the world of medical science fiction they are found everywhere: tiny robots that can zip through blood vessels and intestines, where they can deliver medication, diagnose medical conditions and even directly provide treatment. Although much of this is still firmly in the realm of science-fiction, researchers at Stanford published work last year on an origami-based type of robots, controlled using an external magnetic field. Details can be found in the Nature Communications paper. Continue reading “Tiny Robots That Bring Targeted Drug Delivery And Treatment A Little Bit Closer” →