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

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!

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The insides of a tube-based noise source

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

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

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.

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AARP Swipes Right On Senior Social Network

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

[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.

Hackaday Report: Will 2022 Bring A New Dawn For The Chip Shortage?

As the world begins to slowly pull itself out of the economic effects of the pandemic, there’s one story that has been on our minds for the past couple of years, and it’s probably on yours too. The chip shortage born during those first months of the pandemic has remained with us despite the best efforts of the industry. Last year, pundits were predicting a return to normality in 2022, but will unexpected threats to production such as the war in Ukraine keep us chasing supplies? It’s time to delve into the root of the issue and get to the bottom of it for a Hackaday report.

The Chips Are Down

Empty supermarket shelves in March 2020
Consumers were more interested in toilet paper than chip supply during the lockdown.

Going back to 2020, and as global economies abruptly slowed down in the face of stringent lockdowns it’s clear that both chipmakers and their customers hugely underestimated the effect that the pandemic would have on global demand for chips.

As production capacity was reduced or turned to other products in response to the changed conditions, it was soon obvious that the customers’ hunger for chips had not abated, resulting in a shortfall between supply and demand.

We’ve all experienced the chaos that ensued as the supply of popular varieties dried up almost overnight, and as fresh pandemic waves have broken around the world along with a crop of climate and geopolitical uncertainties it’s left many wondering whether the chip situation will ever be the same again.

Green Shoots In Idaho

An Idaho License plate: "Famous potatoes"
Idaho leads the way in a chip shortage recovery! inkknife_2000, CC BY-SA 2.0

Amidst all that gloom, there are some encouraging green shoots to be seen. While it’s perhaps not quite time to celebrate, there’s a possibility for some cautious optimism. This month brought the hope that Potato Semiconductor might be cutting the sod on a new production capacity for their ultra-fast digital logic in Idaho, and with other manufacturers following suit it could be that we’ll once again have all the chip capacity we can eat.

But the other side of the chip business coin lies with the customer: we all see the chip shortage from our own semi-insider perspective, but have the tastes of the general public returned towards chips? Early signs are that as consumer confidence returns there are encouraging trends in chip consumption taking root, so we’d be inclined to advise our readers to have cautious optimism. If all goes well, you’ll be having your chips by summer.

The prospects for a new dawn in chip production capacity in 2022 look rosy, but there’s a further snag on the horizon courtesy of the Russian invasion of Ukraine. Like so many industries in a globalised economy, the chip industry depends heavily on supplies, consumables, and machinery from beyond the borders of wherever the plants themselves may lie.

In the case of Ukraine there’s a particular raw material whose supply has been severely interrupted, and though we hope for a speedy resolution of the conflict and a consequent resumption of production, the knock-on effect on the production of chips in the rest of the world can not be underestimated. Despite the ramp-up in output led by Idaho, the production of chips globally still relies heavily on Ukrainian sunflower oil. There’s a possibility that an acceptable substitute might be found in canola oil, but it will remain to be seen whether the chip-eating consumers will notice the taste difference.

If you would like to help the people of Ukraine in their hour of need, here are some organisations working on the ground to whom you can donate.

Header image: Daniel Kraft, CC BY-SA 3.0.

Hackaday Podcast 162: Hackaday Prize Is On, Thermal Printers Are So Hot These Days, Cloud Chambers Are Super Cool, And Batteries Must Be Replaceable

Join Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi for your weekly review of the best projects, hacks, and bits of news that we can cram into 45 minutes or so. We’ll look at the latest developments in DIY air-powered engines, discuss the whimsical combination of GitHub’s API and a cheap thermal printer, and marvel at impressive pieces of homebrew biology equipment. We’ve also got an exceptionally polished folding cyberdeck, a bevy of high-tech cloud chambers, and some soda bottles that are more than meets the eye. Finally we’ll go over the pros and cons of today’s super-smart cameras, and speculate wildly about what a new EU law means for our battery powered gadgets.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download, and listen whenever you like.


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