Building A Replica Of An Obscure Romanian Computer

We’ve all seen emulated Apple II and Commodore 64 boards about the place. Few of us have heard of the Romanian ZX Spectrum clone known as the Cobra, let alone any efforts to replicate one. However, [Thomas Sowell] has achieved just that, and has shared the tale with us online.

The Cobra was named for its origins in the city of Brasov – hence, COmputer BRasov. The replica project was spawned for a simple reason. Given that sourcing an original Romanian Cobra would be difficult, [Thomas] realized that he could instead build his own, just as many Romanians did in the 1980s. He set about studying the best online resources about the Cobra, and got down to work.

The build started with board images sourced from Cobrasov.com, and these were used to get a PCB made. [Thomas] decided to only use vintage ICs sourced from the Eastern Bloc for authenticity’s sake, too. Most came from the former USSR, though some parts were of East German, Romanian, or Czechoslovakian manufacture. The project took place prior to the Russian invasion of Ukraine, so there weren’t any hassles shipping across borders.

With everything hooked up and the EEPROMs given a real Cobra ROM image, the computer burst into life. There were some hiccups, with an overheating video IC and some memory glitches. However, with some nifty tweaks and replacements subbed in, the computer came good. Other work involved adding a custom keyboard and modifying 3.5″ floppy drives to work with the system.

Overall, the build is a faithful tribute to what was an impressive piece of engineering from behind the Iron Curtain. [Thomas]’s work also embodies the DIY ethos behind many homebrew Cobra computers built back in the day.

If all this talk has got you curious about the full history of the Cobra and Romania’s underground computer movement, we have everything you’re looking for right here!

picture showing the re-built scale with an extra blue box with electronics on the bottom of it. on the scale, there's a transparent food-grade plastic glass with measurement marks on the side.

Urine Flow Measurement Made Accessible With UroFlow

If you’re dealing with a chronic illness, the ability to continuously monitor your symptoms is indispensable, helping you gain valuable insights into what makes your body tick – or, rather, mis-tick. However, for many illnesses, you need specialized equipment to monitor them, and it tends to be that you can only visit your doctor every so often. Thankfully, we hackers can figure out ways to monitor our conditions on our own. With a condition called BPH (Benign Prostate Hyperplasia), one of the ways to monitor it is taking measurements of urinary flow rate. Being able to take these measurements at home provides better insights, and, having found flow rate measurement devices to be prohibitively expensive to even rent, [Jerry Smith] set out to build his own.

This build is truly designed to be reproducible for anyone who needs such a device. Jerry has intricately documented the project and its inner workings – the 31-page document contains full build instructions, BOM for ordering, PCB description and pinout diagrams, calibration and validation instructions, and even software flowcharts; the GitHub repo has everything else you might need. We’re pleasantly surprised – this amount of documentation isn’t typically seen in hacker projects, and is even more valuable considering that this is a medical device that other hackers in need will want to reproduce.

Graph titled "Flow", with X axis saying "seconds" and Y axis saying "ml/Sec". There's differently colored plots on the graph, each apparently corresponding to a different measurement.For the hardware, [Jerry] took a small digital scale of a certain model and reused its load cell-based weighing mechanism using an HX711 amplifier, replacing the screen and adding an extra box for control electronics. With an Arduino MKR1010 as brains of the operation, the hardware’s there to log flow data, initially recorded onto the SD card, with WiFi connectivity to transfer the data to a computer for plotting; a DS3234 RTC breakout helps keep track of the time, and a custom PCB ties all of these together. All of these things are easy to put together, in no small part due to the extensive instructions provided.

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Casting Metal With A Microwave And Vacuum Cleaner

Metalworking might conjure images of large furnaces powered by coal, wood, or electricity, with molten metal sloshing around and visible in its crucible. But metalworking from home doesn’t need to use anything more fancy than a microwave, at least according to [Denny] a.k.a. [Shake the Future]. He has a number of metalworking tools designed to melt metal using a microwave, and in this video he uses them to make a usable aluminum pencil with a graphite core.

Before getting to the microwave kiln, the pencil mold needs to be prepared. A 3D-printed pencil is first created with the graphite core, and then [Denny] uses a plaster of Paris mixture to create the mold for the pencil. The 3D printed plastic is left inside the mold and placed in the first microwave kiln, which is turned on just enough to melt the plastic out of the mold, leaving behind the graphite core. From there a second kiln goes into the microwave to melt the aluminum.

Once the molten aluminum is ready, it is removed from the kiln and poured in the still-warm pencil mold. This is where [Denny] has another trick up his sleeve. He’s using a household vacuum cleaner to suck the metal into place before it cools, creating a rudimentary but effective vacuum forming machine. The result is a working pencil, at least after he wears down a few razor blades attempting to sharpen the metal pencil. For more information about how [Denny] makes these microwave kilns, take a look at some of his earlier projects.

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Teensy Becomes Tiny Handheld Computer, Plays Emulators

Science fiction predicted that we would one day all carry around tiny computers of great power. While smartphones are great, those predictions were more based on cuter systems that more closely approximated existing computers, with keyboards and screens. [Jean-Marc Harvengt] has built something along those very lines, and it’s called the T-COMPUTER.

This build centers around the mighty Teensy 4.1. That means it’s got an 800 MHz Cortex-M7 processor, 1 MB of RAM, and 8 MB of flash – eclipsing the specs of many retrocomputers of yesteryear. [Jean-MarcHarvengt] has paired the Teensy with a 42-key keyboard and a TFT screen, making a compact handheld computer platform. It’s also got VGA out for display on a bigger screen, along with USB and an old-school Atari joystick port! Power is via a small rechargeable lithium cell on the back, and 16-bit stereo audio is available via a standard 3.5mm jack. There’s also a little GPIO available if you need to interface with something.

It’s capable of emulating the Commodore 64 and Super Nintendo, as well as more obscure systems like the Atari Lynx. And before you ask – yes, it can run DOOM.┬áIt’s a fun little platform that would be enjoyable for retrogaming and hacking on the go. If you want to build your own, files are readily available on Github to recreate the system.

Handheld computer builds are always growing in popularity now that so much computing power can be had in a tiny devboard formats. If you’ve built your own neat little rig, be sure to let us know! Video after the break.

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Hackaday Prize 2022: An Old (and Distinguished) Camera Learns New Tricks

In the 1950s the major Hollywood studios needed impressive cinematic technologies for their epic movies, to both see off the threat from television, and to differentiate themselves from their competitors. For most of them this meant larger screens and thus larger frame film, and for Paramount, this meant VistaVision. [Steve Switaj] is working on one of the original VistaVision cameras made for the studio in the 1950s, and shares with us some of the history and the work required to update its electronics for the 2020s.

VistaVision itself had a relatively short life, but the cameras were retrieved from storage in the 1980s because their properties made them suitable for special effects work. This mostly analog upgrade hardware on this one had died, so he set to and designed a PIC based replacement. Unexpectedly it uses through-hole components for ease of replacement using sockets, and it replaces a mechanical brake fitted to the 1980s upgrade with an electronic pull back on the appropriate reel motor.

The whole thing makes for an interesting delve into some movie history, and also a chance to see some tech most of us will never encounter even if we have a thing for movie cameras.

Intranasal Vaccines: A Potential Off-Ramp For Coronavirus Pandemics

An interesting and also annoying aspect about the human immune system is that it is not a neat, centralized system where you input an antigen pattern in one spot and suddenly every T and B lymphocyte in the body knows how to target an intruder. Generally, immunity stays confined to specific areas, such as the vascular and lymph system, as well as the intestinal and mucosal (nasal) parts of the body.

The result of this is that specific types of vaccines have a different effect, as is demonstrated quite succinctly with the polio vaccines. The main difference between the oral polio vaccine (OPV) and inactivated vaccine (injected polio vaccine, or IPV) is that the former uses a weakened virus that induces strong immunity in the intestines, something that the latter does not. The effect of this is that while both protect the individual, it does not affect the fecal-oral infection route of the polio virus and thus the community spread.

The best outcome for a vaccine is when it both protects the individual, while also preventing further infections as part of so-called sterilizing immunity. This latter property is what makes the OPV vaccine so attractive, as it prevents community spread, while IPV is sufficient later on, as part of routine vaccinations. The decision to use a vaccine like the OPV versus the IPV is one of the ways doctors can tune a population’s protection against a disease.

This is where the current batch of commonly used SARS-CoV-2 vaccines are showing a major issue, as they do not provide significant immunity in the nasal passage’s mucosal tissues, even though this is where the virus initially infects a host, as well as where it replicates and infects others from. Here intranasal vaccines may achieve what OPV did for polio.

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A Drone For The Rest Of Us

As anyone who’s spent Christmas morning trying to shake a quadcopter out of a tree can attest, controlling these fast moving RC vehicles can be tricky and require a bit of practice to master. [Erik] wanted to simplify this a little bit so his children and friends could race with him, and the end result is a drone that only needs two inputs to fly.

The results of his experimentation with simplifying the controls resulted in a “speeder” type drone which attempts to keep a certain distance off of the ground on its own thanks to an extremely fast time-of-flight sensor. The pilot is then left to control the throttle and the steering only, meaning that [Erik] can use pistol-style RC controllers for these machines. They have some similarities to a quadcopter, but since they need to stay level in flight they also have a fifth propeller on the back, similar to an airboat. This allows for a totally separate thrust control than would normally be available on a quadcopter.

The resulting vehicle is immediately intuitive to fly, behaving more like an RC car than a quadcopter. This also required quite a bit of processing power to compute the proper roll and yaw from a single steering input, but after many prototypes the result is impressive, especially since it was also built to use FPV as a means of control. One of the videos below demonstrates this video, and looks extremely fun to fly, and we wouldn’t mind seeing a race with these types of speeders much like we saw in the past with a group of pod-racing quadrotors.

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