Author: Bryan Cockfield

1708 Articles

GLASNOST Is A Computer That Makes Transparency A Priority

July 17, 2023 by 7 Comments

We live in a world where most of us take the transistor for granted. Within arm’s length of most people reading this, there are likely over ten billion of them sending electrons in every direction. But the transistor was not the first technology to come around to make the computer a possibility, but if you go to the lengths of building something with an alternative, like this vacuum tube computer, you may appreciate them just a tiny bit more.

This vacuum tube computer is called GLASNOST, which according to its creator [Paul] means “glass, no semiconductors” with the idea that the working parts of the computer (besides the passive components) are transparent glass tubes, unlike their opaque silicon-based alternatives. It boasts a graphical display on an oscilloscope, 4096 words of memory, and a custom four-bit architecture based only on NOT, NOR, and OR gates which are simpler to create with the bulky tubes.

The project is still a work in progress but already [Paul] has the core memory figured out and the computer modeled in a logic simulator. The next steps are currently being worked through which includes getting the logic gates to function in the real world. We eagerly await the next steps of this novel computer and, if you want to see one that was built recently and not in the distant past of the 1950s, take a look at the Electron Tube New Automatic Computer that was completed just a few years ago.

Remote Code Execution On An Oscilloscope

July 17, 2023 by 10 Comments

There are a huge number of products available in the modern world that come with network connectivity now, when perhaps they might be better off with out it. Kitchen appliances like refrigerators are the classic example, but things like lightbulbs, toys, thermostats, and door locks can all be found with some sort of Internet connectivity. Perhaps for the worse, too, if the security of these devices isn’t taken seriously, as they can all be vectors for attacks. Even things like this Rigol oscilloscope and its companion web app can be targets.

The vulnerability for this oscilloscope starts with an analysis of the firmware, which includes the web control application. To prevent potentially bricking a real oscilloscope, this firmware was emulated using QEMU. The vulnerability exists in the part of the code which involves changing the password, where an attacker can bypass authentication by injecting commands into the password fields. In the end, the only thing that needs to be done to gain arbitrary code execution on the oscilloscope is to issue a curl command directed at the oscilloscope.

In the end, [Maunel] suggests not connecting this oscilloscope to the Internet at all. He has informed the producer about it but as of this writing there has not been a resolution. It does, however, demonstrate the vulnerabilities that can be present in network-connected devices where the developers of the software haven’t gone to the lengths required to properly secure them for use with the modern Internet. Even things not connected to a traditional Internet connection can be targets for attacks.

Adapter Board Expands The Pi Zero

July 17, 2023 by 23 Comments

The standard Raspberry Pi computers have been in short supply for a while now, so much so that people are going to great lengths to find replacements. Whether it’s migrating to alternative single-board computers or finding clones of the Pi that are “close enough”, there are solutions out there. This method of building a full-size Raspberry Pi with all of the bells and whistles using the much-less-in-demand Pi Zero also stands out as a clever solution.

[SpookyGhost] didn’t build this one himself, but he did stumble across it and write a pretty extensive how-to and performance evaluation for the board, which can be found here. The adapter connects to the Zero’s HDMI and USB ports, and provides all the connectors you’d expect from a larger Pi such as the 3B. It’s not a perfect drop-in replacement though — you don’t get the 3.5 mm audio jack, and the micro SD card location doesn’t match up with where it should be on a “real” Pi.

All things considered, this is one of those solutions that seems obvious in retrospect but we still appreciate its elegance. It might disappear as soon as chip shortages stop being an issue, but for now we’ll take any solutions we can. If you don’t already have a Pi Zero on hand, we’ve seen some other successes replacing them with thin clients or even old smartphones.

DIY Laser For Ablating Metal

July 17, 2023 by 51 Comments

For those who wish to go beyond through-hole construction on perfboard for their circuit boards, a printed circuit board is usually the next step up. Allowing for things like surface-mount components, multi-layer boards, and a wider array of parts, they are much more versatile but do have a slight downside in that they are a little bit harder to make. There are lots of methods for producing them at home or makerspace, though, and although we’ve seen plenty of methods for their production like toner transfer, photoresist, and CNC milling, it’s also possible to make them using laser ablation, although you do need a special laser to get this job done.

The problem with cutting copper is that it reflects infra-red, so a higher-wavelength blue green laser is used instead. And because you want to ablate the copper, but not melt the surrounding areas or cut straight through the board, extremely short, high-power pulses are the way to go. Here, the [Munich Fab Lab] is using 9 kW pulses of around 30 microseconds each.  With these specifications the copper is ablated from the surface of the board allowing for fine details in the range of about 20 µm, which is fine enough for just about any circuit board. The design of the laser head itself is worth a look.

Aside from the laser, the rest is standard CNC machine fodder, but with an emphasis on safety that’s appropriate for a tool in a shared workspace, and the whole project is published under an open license and offers an affordable solution for larger-scale PCB production with extremely fine resolution and without the need for any amounts of chemicals for the more common PCB production methods. There is a lot more information available on the project’s webpage and its GitHub page as well.

Of course, there are other methods of producing PCBs by laser if you happen to have a 20 W fiber laser just kicking around.

Reverse Engineering A Classic ThinkPad Battery

July 15, 2023 by 14 Comments

The ThinkPad 701 is an iconic laptop series from the mid-90s and is still highly sought after today because of its famous butterfly keybaord. The laptop itself is tiny even by the standards of the time, so in order to fit a full-size keyboard IBM devised a mechanism where the keyboard splits and slides over itself to hide away as the screen is closed. But, like most 30-year-old laptops, the original batteries for these computers are well past their prime. [polymatt] takes us through all of the steps needed in order to recreate a battery from this era down to the last detail.

He starts by disassembling an old battery with extensive damage from the old, leaky batteries. The first part of the recreation is to measure the battery casing so a new one can be modeled and printed. The control boards for the batteries of these computers were not too sophisticated, so [polymatt] is able to use a logic analyzer with a working unit to duplicate its behavior on an ATtiny microcontroller. With that out of the way, a new PCB is created to host the cloned chip and a new battery pack, made out of 9 NiMH cells is put together.

[polymatt] wanted this build to be as authentic as possible, so he even goes as far as replicating the label on the underside of the battery. With everything put together he has a faithful recreation of this decades-old battery for a famous retro laptop. ThinkPads are popular laptops in general, too, due to their fairly high build quality (at least for their enterprise lineups) and comprehensive driver support especially for Linux and other open-source software projects like coreboot and libreboot.

Thanks to [Roman UA] for the tip!

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Trebuchet Sends Eggs Flying

July 14, 2023 by 7 Comments

Without any sort of restrictions on designs for trebuchets, these medieval siege weapons are known to send 90 kilogram projectiles over 300 meters. The egg-launching trebuchet contest that [AndysMachines] is entering, on the other hand, has a few limitations that dramatically decreased the size of the machines involved. The weight of the entire device is limited to no more than 3 kg, with any physical dimension no more than 300 mm, but that’s more than enough to send an egg flying across a yard with the proper design and tuning for maximum distance.

Trebuchets distinguish themselves amongst other siege weapons by using a falling weight to launch the projectile. The rules of this contest allow for the use of springs, so [AndysMachines] is adding a spring in between the trebuchet arm and the weight in order to more efficiently deliver the energy from the falling weight. More fine tuning of the trebuchet was needed before the competition, though, specifically regarding the stall point for the trebuchet. This is the point where the forces acting on the arm from the projectile and the weight are balanced, and moving this point to allow the projectile to release at a 45-degree angle was needed for maximum distance.

The video goes into a lot of detail about other fine-tuning of a trebuchet like this, aided by some slow-motion video analysis. In the end, [AndysMachines] was able to launch the egg over ten meters with this design. Of course, if you want to throw out the rule book and replace the eggs with ball bearings and the aluminum and steel with titanium, it’s possible to build a trebuchet that breaks the sound barrier.

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Listening To Bats As They Search For Food

July 14, 2023 by 14 Comments

The range of human hearing goes up to about 20 kilohertz, which is fine for our purposes, but is pretty poor compared to plenty of other animal species. Dogs famously can hear up to about 60 kHz, and dolphins are known to distinguish sounds up to 100 kHz. But for extremely high frequencies we’ll want to take a step into the world of bats. Some use echolocation to locate each other and their food sources, and bats like the pipistrelle can listen in to sounds up to 350 kHz. To listen to them you’ll need a device like the π*pistrelle.

The original implementation of the bat detector was based on a Raspberry Pi Pico, from which it gets its name. But there have been several improvements on it in the years since it was first developed. The latest can detect bats when it hears their 350 kHz sonar calls thanks to an ultrasonic microphone and op amp. The device then records the bat sounds and then either heterodynes the sound down or time-expands it to human-audible range so the calls can actually be heard. There’s an LED display on the board as well as three input buttons, but an iOS companion app is available to interact with the device as well.

If you want to know for sure which species is flying around at night, you can use machine learning to help figure that out.