Briefcase Computer Is A Glorious Cyberpunk Build

April 2, 2022 by 3 Comments

There are plenty of gaming laptops on the market these days, but none quite fit the requirements of one [ParticularlyPippin]. Thus, they set out on building their own portable computer, ending up with a rig in a briefcase with a decidedly cyberpunk feel.

We love this?!

The design relies on desktop components, with the idea being to make a machine with better upgradability than a typical laptop. The briefcase itself is a nice deep-shell unit, and was given a wooden baseboard to hold all the components. It was then provided with standoffs and mountings for a Mini-ITX motherboard, as well as all the necessary add-ons like fans and storage. As in many odd-form-factor builds, a PCI-E riser cable comes in handy to hook up the GPU.

As for the user interface, a USB portable monitor is paired with a mechanical keyboard for the appropriate amount of clackity-clack when hacking out in the field. The icing on the cake, however, are the RGB strip backlights controlled via MSI’s software that really make the final result pop.

It’s a tidy portable build and one that hopefully provides [ParticularlyPippin] with the necessary grunt for their work wherever they can tote a briefcase. It’s not the first homebrew luggable we’ve seen, and it won’t be the last; there’s simply something compelling about the briefcase form factor. If you’re cooking up your own in the home lab, don’t hesitate to drop us a line.

This Motorcycle Uses Water!

April 2, 2022 by 38 Comments

Doing the rounds among motorcycle enthusiasts for the last week has been a slightly unusual machine variously portrayed as running on water or sea water. This sounds like the stuff of the so-called “Free energy” fringe and definitely not the normal Hackaday fare, but it comes alongside pictures of a smiling teenager and what looks enough like a real motorcycle to have something behind it. So what’s going on? The answer is that it’s the student project of an Argentinian teenager [Santiago Herrera], and while it’s stretching it a bit to say it runs on sea water he’s certainly made a conventional motorcycle run on the oxygen-hydrogen mix produced from the electrolysis of water. The TikTok videos are in Spanish, but even for non-speakers it should be pretty clear what’s going on.

It’s obvious that the bike is more of a student demonstrator than a road machine, as we’re not so sure a glass jar is the safest of receptacles. But the interesting part for us lies not in the electrolysis but in the engine. it appears to be a fairly standard looking motorcycle engine, a typical small horizontal single. It’s running on a stoichiometric mix of oxygen and hydrogen, something that packs plenty of punch over a similar mix using air rather than oxygen. It would be fascinating to know the effect of this mixture on an engine designed for regular gasoline, for example does it achieve complete combustion, does it burn hotter than normal fuel, and does it put more stress on the engine parts?

You can see something of the bike in the video below the break, and there are a few more videos in his TikTok account. Meanwhile this isn’t the first teenage motorcycle project we’ve featured.

Continue reading “This Motorcycle Uses Water!” →

An 128x64 OLED display with a weird image on it, showing a mouse cursor, date and time in the bottom right corner, and a whole lot of presumably dithered dots

Making Your Own Technically-HDMI OLED Monitor

April 1, 2022 by 17 Comments

One day, [mitxela] got bored and decided to build his own HDMI monitor – the unconventional way. HDMI has a few high-speed differential pairs, but it also has an I2C interface used for detecting the monitor’s resolution and issuing commands like brightness control. In fact, I2C is the backbone for a lot of side channels like these – it’s also one of our preferred interfaces for connecting to cool sensors, and in this case, an OLED display!

[mitxela] describes his journey from start to end, with all the pitfalls and detours. Going through the pinout with a broken hence sacrificial HDMI cable in hand, he figured out how to probe the I2C lines with Linux command-line tools and used those to verify that the display was recognized on the HDMI-exposed I2C bus. Then, he turned to Python and wrote a short library for the display using the smbus bindings – and, after stumbling upon an FPS limitation caused by SMBus standard restrictions, rewrote his code to directly talk to the I2C device node, raising FPS from 2 to 5-10.

From there, question arose – what’s the best software route to take? He tried making a custom X modeline on the HDMI port the display was technically attached to, but that didn’t work out. In the end, he successfully employed the Linux capability called “virtual monitors”, and found out about an interesting peculiarity – there was no mouse cursor to be seen. Turns out, they’re typically hardware-accelerated and overlaid by our GPUs, but in [mitxela]’s case, the GPU was not involved, so he added cursor support to the picture forwarding code, too.

With partial refresh, the display could be redrawn even faster, but that’s where [mitxela] decided he’s reached a satisfactory conclusion to this journey. The write-up is a great read, and if videos are more your forte, he also made a video about it all – embedded below.

We first covered the ability to get I2C from display ports 14 years ago, and every now and then, this fun under-explored opportunity has been popping up in hackers’ projects. We’ve even seen ready-to-go breakouts for getting I2C out of VGA ports quickly. And if you go a bit further, with your I2C hacking skills, you can even strip HDCP!

We thank [sellicott] and [leo60228] for sharing this with us!

Continue reading “Making Your Own Technically-HDMI OLED Monitor” →

The insides of a tube-based noise source

Using A Vacuum Diode To Make The Cleanest Noise Source You’ve Ever Seen

April 1, 2022 by 15 Comments

Noise is an annoying but unavoidable part of any engineering project. Fixing noise issues is hard enough, but even just measuring how much noise an amplifier adds to your signal is tricky without proper equipment like a spectrum analyzer. One other thing that makes noise measurements easier is a good, stable noise source that can serve as a reference: you first measure your amplifier without any input, and then measure it again with the noise source connected. Using a few simple formulas you can then calculate how much noise the amplifier produced.

Building a source that generates exactly the amount of noise that you want, no more and no less, is quite a challenge in itself. Several techniques exist, but [Wolfgang] over at the Electronic Projects for Fun blog decided to go for the classic method of using a vacuum diode. He describes the design and analysis of a noise source based on a 2D3B tube in a detailed article.

The tube in question is a special vacuum diode designed to be operated in saturation, meaning at a current high enough to draw away all the electrons generated by the hot filament. When running in this mode, the output current has a noise spectrum that is almost perfectly white, meaning its power level remains constant across the frequency band. [Wolfgang]’s measurements show a deviation of no more than 0.2 dB between 200 kHz and 200 MHz. This is about as close to perfect as you can get, and covers most of the frequency bands of interest to radio amateurs.

The whole project is built up inside a sturdy metal box, with extensive shielding and line filtering to keep undesired signals from contaminating the clean noise signal. A limiter is also an essential component: should the diode’s filament break, the limiter will prevent the sudden transient from reaching the spectrum analyzer and destroying its (very expensive) input stage.

[Wolfgang] has made a few other noise sources based on various components, which he compares on a separate page, although the 2D3B based one is by far the most stable. We’ve also featured a simple pink noise source, which is useful for audio measurement, as well as white noise sources designed to generate random numbers or simply to help you sleep.

Stresses Revealed With A Polariscope

April 1, 2022 by 13 Comments

There are a lot of ways that stresses can show up, at least when discussing materials science. Cracks in concrete are a common enough example, but any catastrophic failure in a material is often attributable to some stress that couldn’t be withstood. If you’re interested in viewing those stresses before they result in damage to the underlying material, take a look at this DIY polariscope which can view internal stresses in glass and other clear objects.

The polariscope takes its name from the fact that it uses polarized light to view the internal structure of a transparent object such as glass. When the polarized light passes through glass in a certain way, the stresses show up as lighter areas thanks to the stressed glass bending the light back into view. This one is constructed with a polarizing filter placed in front of an LCD screen set to display a completely white image. When glass is placed between the screen and the filter no light is seen through the polariscope unless there are stresses in the glass. Even placing a force on an otherwise un-stressed glass tube can show this effect, and [Advanced Tinkering], this project’s creator, has several other creations which show this effect in striking detail.

The effect can also be observed as colored areas in other plastic materials as well. It’s an interesting tool which can help anyone who frequently works with glass, but it’s also interesting on its own to see clues left behind from the manufacturing process of various household items. We’ve seen some other investigative methods for determining how other household items are mass produced as well, like this project which breaks down the injection molding process.

Continue reading “Stresses Revealed With A Polariscope” →

AARP Swipes Right On Senior Social Network

April 1, 2022 by 19 Comments

Can you believe that Facebook turns 18 this year? One of the troubled teenager’s biggest problems is that not only are the young people still leaving in droves, many of the remaining denizens are 50 or over and susceptible to the various predators and sources of misinformation that plague the site.

Well, AARP wants to change the landscape of social media for those who are approaching or already living out their twilight years. Basically, they want to lure them away from Facebook. The organization spent untold amounts of money creating Senior Planet Community, which is kind of like a baby version of reddit in that the site is broken into interest categories such as photography, gardening, pets, and fitness enthusiasts.

The site was developed by Older Adults Technology Service (OATS), who are an AARP affiliate. OATS were leading computer classes for seniors and moved online during the pandemic, and the idea grew from there.

The main difference is that Senior Planet Community is absolutely free (for now, at least), including a complete lack of advertisements. If Grandma’s gonna unwittingly spend hundreds on micro-transactions, it won’t be taking place here, and not just because there’s no mobile app or games just yet. As far as moderation, there’s a long list of house rules that involve courtesy and encourage the citing of sources. Posts can be reported should they violate the rules.

We’ll see how it goes. There are plenty of bad actors that could pretend to be age 50+, or don’t even have to lie about it. We also wonder how long they’ll be able to go without advertisers.

We’re all getting older, including Zuckerberg. Don’t believe it? Here’s video proof.

Main and thumbnail images via Unsplash.

The cluster of HackRFs described in the article, boards on top of each other, plugged into two 1x4 RF power splitters that are in turn plugged into a 1x2 RF power splitter. An LNA is connected to the input of the final splitter, and a cable goes off the frame from there.

A Gang Of HackRFs Makes For A Wideband SDR

April 1, 2022 by 13 Comments

[Oleg Kutkov] decided to build a wideband SDR – for satellite communication research and monitoring, you know, the usual. He decided on a battery of HackRF boards – entire eight of them, in fact. Two 1×4 and one 1×2 RF splitters and an LNA on their combined RF input made for a good start to the project, and from there, it only got more complex.

HackRF boards can be synchronized with a separate clock source, but you can’t just pull a single clock line to all of them in a star configuration. Thus, he’s built a clock distribution and amplifier board, with 4 ns propagation delay at 1 PPS, and only 10 ns delay at 10 MHz. Then, he integrated that board with the HackRF setup, adding a case, wiring up a purpose-built cable and dealing with the reflections that occurred.

HackRF boards are USB 2.0 and able to generate a stream of data up to 320 MB/s, and there’d be no viable way to aggregate eight 2.0 links into one. To solve that, he’s used eight separate PCI-E to USB 3.0 cards, each of them with one HackRF plugged in, all connected to an AMD Ryzen 9-powered PC through PCI-E risers we typically see used for mining purposes. To tie it all together, he created a gnuradio flowgraph and patched the osmocom source block to enable the external clock synchronization mechanisms he decided to use.

Each HackRF is connected to its own PCIe USB card.

In the end, [Oleg] shows us some promising results – two DVB-S transceivers visible on the waterfall display of the spectrum capture. The work is not over here, to be clear – he’s ran into a few roadblocks. The gnuradio flowgraph doesn’t lend itself well to multi-threading, even on a Ryzen 9 machine, and [Oleg] pledged to rewrite the capture mechanisms in C++ which can be nicely allocated to separate physical CPU cores, something gnuradio is apparently not quite good at.

More importantly, the spectrum captured is not continuous, and [Oleg] questions whether it can be demodulated properly. He had to resort to frequency overlaps due to upsampling, and he’s not quite sure how to compensate for that. Overall frequency stability is also in question. However, from here, seems like most of the work towards building a wideband receiver is done!

[Oleg] is typically seen on Twitter, lately doing some heavy tinkering with Starlink – as Kyiv, the city he’s currently in, is under bombardment of Russian Armed Forces. We can only respect and appreciate the dedication. In January, we’ve covered his work on an USA-imported Tesla LTE modem replacement to fix LTE band incompatibilities in Ukraine, and his blog is a treasure trove of experiments that we are yet to properly comb through, from astrophysics and satellite work to RS485 networks and Linux driver writing.