It’s that time of year again when some parts of our community travel out into the countryside to spend time with each other under canvas in a field somewhere with power and fast internet — it’s hacker camp season. Here in Europe that means it’s the turn of the British hackers to have the year’s large event, in the form of the latest incarnation of Electromagnetic Field. We’ll be there, camera and microphone in hand, and with luck we’ll be able to bring you a flavour of the event.
The atmosphere that comes from being in the company of several thousand like minds is stimulating enough, but what makes these outdoor events special is that the villages become so much more than simply a group of geeks at a table with their laptops. Where else can one find a tea room run by a hackerspace except courtesy of MK Makerspace, or a fully functional pop-up motor racing circuit from Hacky Racers?
This year’s event badge is an interesting one, the ESP32-S3 powered and hexagon-shaped Tildagon. It’s a bold attempt to redefine the event badge away from a one-off trinket into one that lasts across multiple events, with custom “Hexpansions” like the petals on a flower, intended to have new ones appear on an event by event basis.
If you’re going to be at EMF then maybe we can join you for a pint, otherwise we’ll be bringing you the best that we find there. To whet your appetite, here’s something of the last one.
Helicopters are perhaps at their coolest when they’re being used as flying cranes — from a long dangling cable, they can carry everything from cars, to crates, to giant hanging saws.
What you might find altogether more curious are the helicopters that fly around carrying gigantic flat antenna arrays. When you spot one in the field, it’s not exactly intuitive to figure out what they’re doing, but these helicopters are tasked with important geological work!
Although we usually imagine the conditions in Ancient Egypt to be much like the Egypt of today, back during the Holocene there was significantly more rain as a result of the African Humid Period (AHP). This translated in the river Nile stretching far beyond its current range, with many more branches. This knowledge led a team of researchers to test the hypothesis that the largest cluster of pyramids in the Nile Valley was sited along one of these now long since vanished branches. Their findings are described in an article published in Communications Earth & Environment, by [Eman Ghoneim] and colleagues.
The Ahramat Branch and pyramids along its trajectory. (Credit: Eman Ghoneim et al., 2024)
The CliffsNotes version can be found in the accompanying press release by the University of North Carolina Wilmington. Effectively, the researchers postulated that a branch of the Nile existed along these grouping of pyramids, with their accompanying temples originally positioned alongside this branch. The trick was to prove that a river branch once existed in that area many thousands of years ago.
What complicates this is that the main course of the Nile has shifted over the centuries, and anthropogenic activity has obscured much what remained, making life for researchers exceedingly difficult. Ultimately a combination of soil core samples, geophysical evidence, and remote sensing (e.g. satellite imagery) helped to cement the evidence for the existence what they termed the Ahramat Nile Branch, with ‘ahramat’ meaning ‘pyramids’ in Arabic.
Synthetic Aperture Radar (SAR) and high-resolution radar elevation data provided evidence for the Nile once having traveled right past this string of pyramids, also identifying the modern Bahr el-Libeini canal as one of the last remnants of the Ahramat Branch before the river’s course across the floodplain shifted towards the East, probably due to tectonic activity. Further research using Ground Penetrating Radar (GPR) and Electromagnetic Tomography (EMT) along a 1.2 km section of the suspected former riverbed gave clear indications of a well-preserved river channel, with the expected silt and sediments.
Soil cores to a depth of 20 and 13 meters further confirmed this, showing not only the sediment, but also freshwater mussel shells at 6 meter depth. Shallow groundwater was indicated at these core sites, meaning that even today subsurface water still flows through this part of the floodplain.
These findings not only align with the string of pyramids and their causeways that would have provided direct access to the water’s edge, but also provided hints for a further discovery regarding the Bent Pyramid — as it’s commonly known — which is located deep inside the desert today. Although located far from the floodplain by about a kilometer, its approximately 700 meters long causeway terminates at what would have been a now extinct channel: the Dahshur Inlet, which might also have served the Red Pyramid and others, although evidence for this is shakier.
Altogether, these findings further illustrate an Ancient Egypt where the Old Kingdom was followed by a period of severe changes, with increasing drought caused by the end of the AHP, an eastwardly migrating floodplain and decreased flow in the Nile from its tributaries. By the time that European explorers laid eyes on the ancient wonders of the Ancient Egyptian pyramids, the civilization that had birthed them was no more, nor was the green and relatively lush environment that had once surrounded it.
There are times when tiny displays no longer cut it. Whether you want to build a tablet or reuse some laptop displays, you will eventually deal with LVDS and eDP displays. To be more exact, these are displays that want you to use either LVDS or eDP signaling to send a picture.
Of the two, LVDS is the older standard for connecting displays, and eDP is the newer one. In fact, eDP has mostly replaced LVDS for things like laptop and tablet displays. Nevertheless, you will still encounter both of these in the wild, so let’s start with LVDS.
The name “LVDS” actually comes from the LVDS signaling standard (Low-Voltage Differential Signaling), which is a fairly generic data transfer standard over differential pairs, just like RS485. Using LVDS signaling for embedded display purposes is covered by a separate standard called FPD-Link, and when people say “LVDS”, what they’re actually talking about is FPD-Link. In this article, I will also use LVDS while actually talking about FPD-Link. Barely anyone uses FPD-Link except some datasheets, and I’ll use “LVDS” because that’s what people actually use. It’s just that you deserve to know the distinction so that you’re not confused when someone mentions LVDS when talking about, say, industrial machinery.
Both LVDS and eDP run at pretty high frequencies – they’re commonly used for color displays with pretty large resolutions, so speed can no longer be a constraint. eDP, as a successor technology, is a fair bit more capable, but LVDS doesn’t pull punches either – if you want to make a 1024 x 768 color LCD panel work, you will use LVDS, sometimes parallel RGB – at this point, SPI just won’t cut it. There’s a lot of overlap – and that’s because LVDS is basically parallel RGB, but serialized and put onto diffpairs. Let me show you how that happened, and why it’s cool.
Like most waves in the electromagnetic spectrum, radio waves tend to bounce off of various objects. This can be frustrating to anyone trying to use something like a GMRS or LoRa radio in a dense city, for example, but these reflections can also be exploited for productive use as well, most famously by radar. Radar has plenty of applications such as weather forecasting and various military uses. With some software-defined radio tools, it’s also possible to use radar for tracking aircraft in real-time at home like this DIY radar system.
Unlike active radar systems which use a specific radio source to look for reflections, this system is a passive radar system that uses radio waves already present in the environment to track objects. A reference antenna is used to listen to the target frequency, and in this installation, a nine-element Yagi antenna is configured to listen for reflections. The radio waves that each antenna hears are sent through a computer program that compares the two to identify the reflections of the reference radio signal heard by the Yagi.
Even though a system like this doesn’t include any high-powered active elements, it still takes a considerable chunk of computing resources and some skill to identify the data presented by the software. [Nathan] aka [30hours] gives a fairly thorough overview of the system which can even recognize helicopters from other types of aircraft, and also uses the ADS-B monitoring system as a sanity check. Radar can be used to monitor other vehicles as well, like this 24 GHz radar module found in some modern passenger vehicles.
There’s always an appeal to a cool-looking computer case or cyberdeck – and with authentic-looking Vault-Tec style, [Eric B] and [kc9psw]’s fallout-themed cyberdeck is no exception.
The case looks like it came straight out of one of the Fallout games and acts the part: while (obviously) not capable of withstanding a direct nuclear bomb impact, it can protect the sensitive electronics inside from the electromagnetic pulse and shockwave that follows – if you keep it closed.
And it’s not just the case that’s cool: This cyberdeck is packed full of goodies like long-range radios, SDRs, ADSB receivers, a Teensy 4.1, and dual Raspberry Pis. But that’s just the hardware! It also comes with gigabytes upon gigabytes of Wikipedia, Wikihow, TED talks, and other information/entertainment, for the less eventful days in the wastelands.
If you, too, would like to have one, fret not! The parts list and design files are public, even though some assembly is required.
(a) The 12 permanent magnet holder subsegments. (b) The 16 planar, circular toroidal field coils are positioned inside the water-jet cut support structure. (c) The glass vacuum vessel is joined by 3D-printed low-thickness couplers. Glass ports were hot welded to the torus. (Credit: T.M. Qian et al., 2023)
When you think of a fusion reactor like a tokamak or stellarator, you are likely to think of expensive projects requiring expensive electromagnets made out of exotic alloys, whether superconducting or not. The MUSE stellarator is an interesting study in how to take things completely in the opposite direction. Its design and construction is described in a 2023 paper by [T.M. Qian] and colleagues in the Journal of Plasma Physics. The theory is detailed in a 2020 Physical Review Letters paper by [P. Helander] and colleagues. As the head of the Stellarator Theory at the Max Planck Institute, [P. Helander] is well-acquainted with the world’s most advanced stellarator: Wendelstein 7-X.
As noted in the paper by [P. Helander] et al., the use of permanent magnets can substantially simplify the magnetic-field coils of a stellarator, which are then primarily used for the toroidal magnetic flux. This simplification is reflected in the design of MUSE, as it only has a limited number of identical toroidal field coils, with the vacuum vessel surrounded by 3D printed structures that have permanent magnets embedded in them. These magnets follow a pattern that helps to shape the plasma inside the vacuum vessel, while not requiring a power supply or (at least theoretically) cooling.
Naturally, as noted by [P. Helander] et al, a limitation of permanent magnets is their limited field strength, inability to be tuned, and demagnetization at high temperatures. This may limit the number of practical applications of this approach, but researchers at Princeton Plasma Physics Laboratory (PPPL) recently announced in a self-congratulatory article that they will ‘soon’ commence actual plasma experiments with MUSE. The lack of (cooled) divertors will of course limit the experiments that MUSE can be used for.
