Braino! Takes The Cheap Yellow Display To School

These days, it’s common to give even very young children a mobile device loaded up with educational software that aims to improve everything from basic motor skills to reading and arithmetic. But even the cheapest phone or tablet isn’t the kind of thing most parents would like to see get destroyed, and there’s always a concern about giving children a device that’s capable of connecting to the Internet.

Which is where Braino! from [Ankush Pandit] comes in. This suite of applications can be easily flashed to a common Cheap Yellow Display to turn it into a legitimate educational tool. Combined with a 3D printed case, the total cost of the build is low enough that you don’t have to feel bad about handing it off to even the roughest of youngsters.

[Ankush] makes it clear that this project isn’t trying to sell you anything. You’re responsible for picking up a compatible CYD and installing Braino via the web flashing application. The software is released under the GPLv3 license, and it contains no ads, user accounts, or cloud connectivity. We know not everyone is thrilled with how much time young kids spend staring at screens these days, but opinions on modern parenting aside, it’s hard to find fault with the way things have been implemented here.

When the parent sets up Braino they can pick which of the 40 games can be accessed, allowing the experience to be tailored to the individual child’s age and ability. Should you decide to enable Bluetooth, some of the games even support wireless multiplayer between devices.

The commonality of the Cheap Yellow Display is one of its best features, and Braino does an excellent job of showing why that’s so important. Trying to develop a project like this without a standardized platform of some type would be a non-starter, but when anyone can get a CYD sent to their house from Amazon and flash it right from the browser, it’s makes the whole thing far more accessible.

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This Week In Security: Critical DNS Keys Rotated, Hacking Freezers Isn’t Cool, OpenAI Spies On Itself, And Advanced Hardware Wallet Hacks

Critical Internet keys changed this week. Did you notice?  The keys behind DNSSEC, the system for cryptographically validating DNS responses, rolled over on October 11 2026. This is the second time the DNSSEC keys have rotated since the system was implemented, and the first time in 2018 didn’t exactly go entirely smoothly.

DNS is what resolves a host name and turns it into an IP address. It underpins web browsing, email, and just about every other connection. It’s also a very early Internet protocol, written in both a simpler, less paranoid era, and an era where encryption was computationally expensive and legally problematic. DNS offers little protection against malicious actors spoofing responses, and the impacts range from phishing to redirecting email to just about any other manipulation of connections you can image.

DNSSEC addresses this by creating a chain of trust between DNS resolvers — the servers that forward the DNS query into the DNS infrastructure and return the results — and the global DNS servers. Part of this chain of trust is the root key that each resolver must have and trust, and this key is what changed this week.  DNSSEC resolvers automatically watch for a new root of trust key, but the key must be signed by the previous root of trust, and is checked for at least 30 days before it is trusted.  If someone were able to issue a bogus certificate, they would have to maintain control of the infrastructure for over a month before DNS resolvers would trust it.

The process of distributing the new key actually began more than a year ago, on January 11, 2025, to give DNSSEC resolvers time to get the new key. DNSSEC services should have had plenty of time to obtain and trust the new key, and unless DNS stopped working for you this week, they did their job.

The next major change for DNSSEC will require more profound changes to deploy a new signing algorithm that will be post-quantum secure.

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Disposing Of PLA And Why Composting Is Not An Option

The ‘biofriendly’ nature of poly(lactic acid) (PLA) filament often gets touted as one of its main advantages over alternatives like PETG, but even a modicum of research ought to inform a person that the biodegrading feature of PLA is only true for pure PLA without additives and at temperatures at or above its glass transition temperature (Tg). Thus the results of a year-long experiment by [I built a thing] shouldn’t be too surprising.

After burying said PLA in the garden like any self-respecting person does who tries to dispose of some evidence, the PLA suffered through a European winter and very hot, dry summer, before being dug up again recently for inspection and testing. Although not the first time that someone has tested this, it’s a good reminder considering just how much PLA filament is used each year.

In total three sample sets were used, one being the control, the other two buried in soil and compost respectively. A visual inspection showed no major difference, and a tensile strength test also showed no statistically significant change among all three sample sets. The experiment could have been concluded here, but instead calorimetry was used in a laboratory setting to see whether exposure to microbes as commonly found in soil does anything significant.

This isothermal microcalorimetry test was performed at the University of Basel, effectively to answer the question whether there’s anything in the PLA samples that can feed said microbes. As it turns out, the answer is a resounding ‘no’, with microbial activity within the presence of PLA dropping off even quicker presumably due to there being less volume available for nutrients.

When [I built a thing] contacted a large number of commercial biodegrading facilities in Switzerland, Germany and the USA, many would happily take PLA, but none of them would accepted 3D-printed PLA parts, which says a lot. The primary reason for this appears to be that even under industrial composting conditions it simply takes too long for these facilities to consider these to be economical to compost.

With PLA primarily degrading via hydrolysis, it needs to be exposed to the right conditions for this process to not take an eternity. You can of course use something like PHA instead, which doesn’t require this hydrolysis step to be biodegradable. Overall PLA is quite a crummy material, with it also suffering from embrittlement due to crystallization that will happily turn a spool of PLA into lots of sad fragments. This makes PETG into a very common and very attractive alternative to PLA.

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Running DOOM (Sort Of) On A Sonoff Smart Switch

It’s often said in this community that DOOM can be made to run on anything, and as time goes on, that’s becoming more and more accurate. We’re at the point now that every “normal” device seems to have some version of the iconic 1993 shooter, so now there’s nothing left but to start working on the more oddball targets.

As a perfect example, [piuppi] recently wrote in to share their efforts to get DOOM — or at least something that looks like it — running on the Sonoff Basic R2 smart switch. We say something that looks like it because the game you’re seeing in the video below isn’t actually DOOM. In fact, it’s not even really a full game. It’s essentially a tech demo that’s capable of rendering graphical data pulled from the game, but only within the confines of simplistic map. Still, not bad for something designed to turn lamps on and off.

The GitHub repo includes excellent documentation should you want to rip and tear on your own Sonoff device. As you might expect the process is a bit involved, and does require you to provide your own copy of DOOM for the script to extract the necessary data from. After it’s setup, you can hit the switch from any browser on the local network and take out your frustrations on the state of modern home automation on some imps. The best part is, even after the game is installed and running on the switch, the device still actually works as a switch.

But don’t worry. Even in the unlikely event that we run out of devices that can be hacked to run DOOM, there’s still a whole world of gadgets out there that need their own port of Duke Nukem 3D.

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Another Wireless Chip Has A Hidden SDR Revealed

The news of the past couple of weeks has seen the ESP32 turned into an software-defined radio (SDR) thanks to a hidden baseband mode, an exciting development by anyone’s standards. It seems unexpected SDRs are like busses in that you wait for ages and two turn up at once, because hot on the heels of the ESP32 story is [Samson1te], revealing the SDR functionality hidden within the LR2021 LoRa chip. This one is especially interesting because as well as a 2.4 GHz radio, the chip sports a radio that works from 150 to 960 MHz.

We’re indebted to them for posting this in a comment on our receive converter post, as a complimentary project to the ESP32 one. It gives a 16-bit SDR with receive and transmit, however as with the ESP32 it’s early days and we hope great things lie ahead. There are comprehensive docs available, should you wish to enter the fray. Currently the main demo is P25 digital voice.

If you’re interested, you can follow our coverage of the ESP32 SDR.

Using Optical Waveguide Arrays To Make Sheets Sense Shapes

Determining the shape of an object which can change dynamically is a bit of a challenge, one that especially vexes those who are really into Virtual Reality. Sensing the orientation of various limbs and appendages usually requires external sensors like cameras, or limit the focus to specific details like just the hands and fingers of the player. A more comprehensive and potentially flexible approach might be possible using optical waveguides, as demonstrated by [Qifan Yu] et al. in a recent article in Advanced Intelligent Systems.

Waveguides are structures that guide electromagnetic waves, with optical waveguides such as used here targeting EM radiation in the optical band. This can even allow for the use of cheap and plentiful optical fiber, though here custom elastomeric waveguides are manufactured. These are laid out onto the sheet in a double-sided, overlapping zig-zag pattern, which allows for easy reconstruction of the shape of said sheet based on how the wave propagation through the waveguide changes.

By characterizing the behavior of the signals through the waveguide, its shape and thus that of the sheet can be reconstructed. This was then demonstrated to be accurate by wrapping the sheet around a volunteer’s arm, elbow and hand, detecting the flexing and movement of individual joints.

Although fairly bulky in the demonstrated configuration and with an unoptimized algorithm, it’s conceivably something that can be miniaturized to the point where it can be woven into regular fabric. This could make for sensor sheets that could track the configuration of everything from robots to human bodies for something like VR purposes.

45 Years Later, The Sinclair ULA Design Documents Surface

In the 8-bit home computer boom of the early 1980s, Sir Clive Sinclair’s machines were always among the cheapest on the market, often packing a surprising level of sophistication in their limited hardware. If there was one component that was key to their success it was the Ferranti ULA, or Uncommitted Logic Array, a clever way to make an ASIC from a chip containing a library of logic parts ready made. The Sinclair ULAs have been reverse engineered, but their full details have remained a mystery. Until now it seems, because here’s [Happy Little Diodes] with a treasure trove of original Ferranti design documents covering all the Sinclair parts.

The documents were picked up on eBay, and contain folders with printouts, engineering drawings, and hand written design notes. They cover the full range of Sinclair products of the era, including the ZX81 and Spectrum, the ZX printer, the Microdrive, the Spectrum Interface 1, and even the curious little flat screen TV. Oddly the IP is now held by the satellite broadcaster Sky as the holder of Amstrad’s portfolio, but fortunately Sky have recognised their historical importance and allowed their sharing with minimal changes. They’re all catalogued with download links in a Google spreadsheet, so dig in and see what you can find. Of particular interest are the ULAs that haven’t been reverse engineered yet, and the subtle differences between different versions of the same ULA as the engineers tried to fix bugs. The video is below the break.

If you’re curious about the ULA and Ferranti, we linked to a period film about it.

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