2026-04-29 04:00:18
Australia’s payphones are an iconic part of the national landscape, even if they’re not as important as they once used to be. However, they’re having a resurgence of late, in part thanks to a new national pastime—the sport of Payphone Tag!
Created by [Alex Allchin], the game is simple. To play, you first sign up on the website and get your emoji and 5-digit PIN. You then go out and find a payphone, dial the Payphone Tag number, and enter your PIN when prompted. This lets you “capture” the phone, raising your score in the game. If a phone is already captured, no matter—just head out there, dial the number, and key in your own PIN to steal it. You can also push your score even higher by capturing three payphones in a triangle on the map to get bonus points.
It’s a fun geospatial game that’s also free to play, because Telstra made payphone calls free back in 2022. It might cost you a bit to get out to some phones, but there are plenty you can reach with the aid of free public transport at the moment, anyway. Protip—at the time of writing, there are a ton of easy captures to be had on Kangaroo Island. It might just cost you a pretty penny to get out there. Have at it!
We’d love to see some stats from Telstra as to whether this is making a dent in overall payphone usage rates. In any case, there were 800 players in the last 7 days and a full 36,640 captures so far, so a lot is happening out there. We fully expect to see this concept spread to other nations in turn, though it might be less attractive in places where you still need to dig out a coin to make a call.
We’ve featured a few payphone hacks over the years. If you’re doing something rad with these telecommunication devices of yesteryear, we’d love to hear about it on the tipsline.
2026-04-29 02:30:20
With all the battery technologies and modern low-current sleep modes in most microcontrollers, running a sensor and microcontroller combo off-grid and far away from any infrastructure is usually not too difficult a task. Often these sorts of systems can go years without maintenance or interaction. But for something that still has to be off-grid but needs to do some amount of work every now and then like actuating a solenoid or quickly turning a servo, these battery-based systems can quickly run out of juice. To solve that problem, [Nelectra] has come up with this high-power capacitor-based IoT system.
Although supercapacitors don’t tend to have the energy density of batteries, they’re perfectly capable of powering short tasks in off-grid situations like this. They’re also typically able to tolerate lower voltages, extreme temperatures, and shock better than most batteries as well. A small solar cell on the top of this device keeps it topped up, and when running in deep sleep mode can hold a charge for up to six days. In more real-world applications supporting sensors, relays, or other actuators, [Nelectra] has found that it can hold a charge for around three days. When a quick burst of power is needed, it can deliver 1.5 A at 9 V or 500 mA at 24 V.
[Nelectra]’s stated goal for this build is to bridge low-power energy harvesting and practical field actuation, enabling maintenance-free systems such as irrigation control and remote switching without batteries, going beyond simple sensor applications while not relying on always-on power from somewhere else. Something like this would work really well in applications like this automated farm, which has already provided some unique solutions to intermittent power and microcontroller applications that need very high reliability.
2026-04-29 01:15:59
If you don’t already have your tickets to Hackaday Europe, pick them up now. The clock is ticking! Today, we’d like to announce our keynote speaker, the remainder of our featured talks, and two more workshops. (And if you want workshop tickets, which always go fast, get those soon!)
Hackaday Europe is super excited to welcome back Hackaday Superfriend [Sprite_tm] to kick off the event with a keynote talk on how he made a retrogaming PC from bare silicon. Don’t miss it.
Jeroen Domburg
What if you could build a retro-gaming PC from bare chips? No emulation. No ancient hardware. Jeroen walks through designing a compact 486 SBC with modern amenities, starting from the silicon up.
Turn a PlayStation 4 optical pickup into a high-speed dermal atomic force microscope. Edwin shows how hardware hacking and deep learning combine to assess skin conditions and potentially detect stress non-invasively.
Ten years of taking robots into the real outdoors, through sand, mud, and wildfire zones. Erin shares what happens when nature-inspired machines meet nature itself, and what she’s learned building them.
Our physical intuitions about inertia, momentum, and gravity shape how we play instruments. Stephen explores what happens when digital instruments simulate these properties and what new musical possibilities emerge.
As tech grows more opaque, there’s an urgent need to return to simple, hackable systems. Sylvain presents an ambient computing vision; devices that blend into life rather than dominate it.
A 3D printer made of Lego. DOOM running in a PDF. These are Hack Club projects built by teenagers. Alex shares the tools, culture, and community behind hardware hacking at scale for young makers.
Electric signals travel in two directions in a coaxial cable, and they don’t mix on the way. Michael explains transmission line theory and demonstrates why it matters for RF and high-speed digital design.
RF, high-speed USB, analog chaos. Building a 20MHz continuous bandwidth, 3GHz-capable SDR without breaking a $50 BOM, achievable with a single FPGA on a carrier board.
A 20-minute tour of the fluid kernel architecture, the Miosix RTOS as a practical implementation, and 18 years of hard-won tips for writing efficient C++ on microcontrollers.
A hands-on workshop covering the basics of hardware fault injection, power glitching, EMFI, and practical comparisons of tools available to hardware security researchers and curious makers.
A practical dive into mesh networking with Meshtastic and Reticulum; installing, configuring, and communicating across decentralized mesh programs. Leave with hands-on experience and a new view of off-grid connectivity.
[If you read this far, you probably want tickets. Just sayin’.]
2026-04-28 23:30:09
The problem with tube based audio is that it has so often been hijacked by people for whom the bragging rights of having a tube amplifier outweigh the benefits, or the sheer fun of building the thing. [Bettina Neumryr] makes a speciality of building projects featured in old electronics magazines, and her latest, a tube amplifier from 1955, is a fantastic antidote to the gold-plated silliness of audiophile tube amplifiers.
Design wise it’s relatively straightforward, with a preamplifier before a two-tube transformerless splitter circuit driving a push-pull output. She dives into the circuit a little, noting its feedback circuit to the cathode of the first splitter tube. There’s an accompanying power supply, a classic tube rectifier design that incorporates a hefty low-pass filter with a giant choke.
We particularly like her choice of chassis — while it’s possible to pay silly money for a tube chassis in 2026 she’s taken a much more down to earth approach with a pair of baking trays. We’re being honest here, they look surprisingly good. Component choices are limited by what’s available so most parts come from the junk box including the output transformer which causes her issues later. There’s a lot of mumbo-jumbo about tube amplifier layout, and she wisely sidesteps some of it.
The result after a few mishaps and a bit of unintended oscillation, is an amp which shows promise, but has distortion due to that transformer. We think she’ll have no problems sourcing a better one, which should bring that distortion figure into the acceptable range. You can watch the whole video below the break, and if that’s got you hooked, you can see one of our own youthful follies.
2026-04-28 22:00:20
Considering how integral it is to our modern way of life, you could be excused for thinking that the Global Positioning System (GPS) is a product of the smartphone era. But the first satellites actually came online back in 1978, although the system didn’t reach full operational status until April of 1995. While none of the active GPS satellites currently in orbit are quite that old, several of them were launched in the early 2000s — and despite a few tweaks and upgrades, their core technology isn’t far removed from their 1990s era predecessors.
But in the coming years, that’s finally going to change. Just last week, the tenth GPS III satellite was placed in orbit by a SpaceX Falcon 9 rocket. Once it’s properly configured and operational, it will join its peers to form the first complete “block” of third-generation GPS satellites. Over the next decade, as many as 22 revised GPS III satellites are slated to take their position over the Earth, eventually replacing all of the aging satellites that billions of people currently rely on.
So what new capabilities do these third-generation GPS satellites offer, and why has it taken so long to implement needed upgrades in such a critical system?
To understand the future of GPS, it’s helpful to look at its past. Developed by the United States military during the Cold War, what we now call GPS was originally known as Navigation System with Timing and Ranging (NAVSTAR). While the intent was always to allow civilian use of NAVSTAR, the equipment necessary to receive the signal and get a position was cumbersome and expensive.
There was little public interest in the system until Korean Air Lines Flight 007 was shot down in 1983 after mistakenly entering the Soviet Union’s airspace. With the lifesaving potential of NAVSTAR clearly evident, pressure started building on the industry to develop smaller and more affordable receivers — GPS as we know it was born.
That the development of such devices was possible in the first place was thanks to the design of NAVSTAR. Each satellite in the constellation broadcasts a timed radio signal which receivers on the ground use to compute their distance from the source. By comparing the signals from multiple satellites, a receiver can plot its position without the need for any local infrastructure. Since the process is entirely one-way, it could be freely used by any device that can receive and decode the signal.
But while this operational simplicity was key to the proliferation of cheap ubiquitous GPS receivers, there’s certainly room for improvement given more modern technology. When NAVSTAR was designed knowing where a receiver was located within a radius of a few meters was more than sufficient, but today there’s a demand for greater accuracy by both civilian and military users. Given the essentially incalculable value of GPS to the global economy, improving reliability is also paramount. Not only has GPS jamming and spoofing become trivial, but even without the involvement of bad actors, legacy GPS struggles in urban environments.
Plans to deliver improved performance in these areas have been in the works for decades, with the United States Congress first authorizing the work on what would become GPS III all the way back in 2000. But when working on a system so critical that even a few minutes of downtime could put the entire planet into turmoil, such changes don’t come easy.
While modern GPS receivers are more sensitive than those in the past, there’s simply no getting over the fact that signals coming from a satellite more than 20,000 kilometers away will be by their very nature weak. So not only is it relatively easy for adverse environmental conditions to block or hinder the signal, but it doesn’t take much to override the signal with a local transmitter if somebody is looking to cause trouble.
As such, one of the key goals of the GPS III program was to deliver higher transmission power. This will lead to better reception for all GPS users across the board, but the new satellites also offer some special modes that offer even greater performance.
In addition to the backwards compatible signals transmitted by GPS III satellites, there’s also a new “Safety of Life” signal. This signal is transmitted at a different frequency, 1176 MHz, and at a higher power, so compatible receivers should hear it come in at approximately 3 dB above the “classic” signal. It’s intended primarily for high-performance applications such as aviation, but as compatible receivers get cheaper, it will start to show up in more devices.
These improvements should be enough for civilian use, but the military has higher expectations and operates under more challenging conditions. In such cases, future GPS III satellites will come equipped with a high-gain directional antenna that can project a “spot beam” signal anywhere on Earth. For receivers located within the beam, which is estimated to be a few hundred kilometers in diameter, the received signal from the satellite will be boosted by up to 20 dB. In contested environments, this should make it far more resistant to jamming and spoofing.
The new signals being transmitted by GPS III satellites won’t just be louder than their predecessors, they’ll gain some new features as well.
For one thing, GPS III satellites will transmit a standardized signal known as L1C which offers interoperability with other global navigation systems such as Europe’s Galileo, China’s BeiDou, the Indian Regional Navigation Satellite System (IRNSS), and Japan’s Quasi-Zenith Satellite System. In theory a compatible receiver will be able to process signals from any combination of these systems simultaneously, improving overall performance.
The new satellites will also support the L2C signal. While this signal was technically available on earlier generation satellites, it’s still not considered fully operational and its adoption is expected to accelerate as more GPS III satellites come online. Compared with the legacy GPS protocol, L2C offers improved faster acquisition of signal, better error correction, and a more capable packet format.
To make GPS III transmissions even more secure, the military is also getting their own signal known as M-code. As you might expect, little is publicly known about M-code currently, but it’s a safe bet that it utilizes encryption and other features to make it more difficult for adversaries to create spoofed transmissions. For what it’s worth, a recent press release from the US Space Force claims that the use of M-code makes the next-generation GPS satellites “three-times more accurate and eight times more resistant to jamming than the previous constellation.”
Although all ten GPS III satellites are now in orbit, that doesn’t mean the constellation is complete. Starting in 2027, a new fleet of revised satellites known as GPS IIIF will start launching. They will take the lessons learned from the initial GPS III deployment to create a smaller, lighter, and more efficient platform that should have a service life of at least 15 years.
They’ll also include new in-development equipment that wasn’t quite ready for deployment when the current GPS III satellites were being assembled. This includes optical reflectors that will allow ground stations to more accurately track the position of each satellite, laser data links that will allow high-speed communication between satellites, and an improved atomic clock known as the Digital Rubidium Atomic Frequency Standard (DRAFS).
Of course, the vast majority of the people who use GPS every day will never be aware of all the changes and improvements happening behind the scenes. When they get a new phone with a GPS III-compatible receiver, they may notice that their navigation app locks on a bit faster or that the position shown on the screen is a little closer to where they are actually standing, but only if they are particularly attentive. But that’s entirely by design — the most important aspect of implementing GPS III is making the whole process as invisible as possible.
2026-04-28 19:00:41
There’s a rule of thumb when it comes to FDM printing that overhangs are really only possible to an angle of around 45 degrees or so. If you try to squirt out plastic with nothing supporting it, it just goes everywhere. However, a new slicer hopes to enable printing up to 90-degree overhangs with some creative techniques.
The software that enables this is called WaveOverhangs, and currently exists as a fork of OrcaSlicer. The idea is straightforward enough — using unique toolpathing to create rings of deposited material that fasten to those laid down before them in the same layer. Thus as the printer lays down a layer into bare space, the deposited plastic is, ideally, able to fix on to the supported edge. As the next ring is laid down, it grabs on to the cooled ring laid down before it, and so on. The idea is inspired by wave propagation, hence the name. You can see a demonstration of the software in the video below by [Cocoanix 3D Printing].
It’s still a very new technique. The slicer has a whole bunch of knobs to turn and two different algorithms. Get the settings just right and you can print horizontal overhangs successfully. There aren’t exactly presets yet, this is something to explore with trial and error. If you test it out, don’t forget to upload your results to the Community Gallery so the developers can see what works and what doesn’t.
We’ve explored how smart slicers can do amazing things before, too, particularly when it comes to things like bridging.
