Creating An Ultra-Stable Lunar Clock With A Cryogenic Silicon Cavity Laser

March 4, 2026 by Maya Posch No comments

Phase-coherent lasers are crucial for many precision tasks, including timekeeping. Here on Earth the most stable optical oscillators are used in e.g. atomic clocks and many ultra-precise scientific measurements, such as gravitational wave detection. Since these optical oscillators use cryogenic silicon cavities, it’s completely logical to take this principle and build a cryogenic silicon cavity laser on the Moon.

In the pre-print article by [Jun Ye] et al., the researchers go through the design parameters and construction details of such a device in one of the permanently shadowed regions (PSRs) of the Moon, as well as the applications for it. This would include the establishment of a very precise lunar clock, optical interferometry and various other scientific and telecommunication applications.

Although these PSRs are briefly called ‘cold’ in the paper’s abstract, this is fortunately quickly corrected, as the right term is ‘well-insulated’. These PSRs on the lunar surface never get to warm up due to the lack of an atmosphere to radiate thermal energy, and the Sun’s warm rays never pierce their darkness either. Thus, with some radiators to shed what little thermal energy the system generates and the typical three layers of thermal shielding it should stay very much cryogenic.

Add to this the natural vacuum on the lunar surface, with PSRs even escaping the solar wind’s particulates, and maintaining a cryogenic, ultra-high vacuum inside the silicon cavity should be a snap, with less noise than on Earth. Whether we’ll see this deployed to the Moon any time soon remains to be seen, but with various manned missions and even Moon colony plans in the charts, this could be just one of the many technologies to be deployed on the lunar surface over the next few decades.

Neither Android Nor IOS: DIY Smartphone Runs On ESP32!

March 4, 2026 by Tyler August 3 Comments

You may or may not be reading this on a smartphone, but odds are that even if you aren’t, you own one. Well, possess one, anyway — it’s debatable if the locked-down, one-way relationships we have with our addiction slabs counts as ownership. [LuckyBor], aka [Breezy], on the other hand — fully owns his 4G smartphone, because he made it himself.

OK, sure, it’s only rocking a 4G modem, not 5G. But with an ESP32-S3 for a brain, that’s probably going to provide plenty of bandwidth. It does what you expect from a phone: thanks to its A7682E simcom modem, it can call and text. The OV2640 Arducam module allows it to take pictures, and yes, it surfs the web. It even has features certain flagship phones lack, like a 3.5 mm audio jack, and with its 3.5″ touchscreen, the ability to fit in your pocket. Well, once it gets a case, anyway.

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Old Desk Phone Gets DOOM Port

March 3, 2026 by Lewin Day 2 Comments

Old desk phones are fairly useless these days unless you’re building a corporate PBX in your house. However, they can be fun to hack on, as [0x19] demonstrates by porting DOOM to a Snom 360 office phone.

The Snom 360 is a device from the early VoIP era, with [ox19] laying their hands on some examples from 2005. The initial plan was just to do some telephony with Asterisk, but [ox19] soon realized more was possible. Digging into a firmware image revealed the device ran a Linux kernel on a MIPS chip, so the way forward became obvious.

They set about hacking the phone to run DOOM on its ancient single-color LCD. Doing so was no mean feat. It required compilation of custom firmware, pulling over a better version of BusyBox, and reworking doomgeneric to run on this oddball platform. It also required figuring out how the keyboard was read and the screen was driven to write custom drivers—not at all trivial things on a bespoke phone platform. With all that done, though, [0x19] had a dodgy version of DOOM running slowly on a desk phone on a barely-legible LCD display.

Porting DOOM is generally a task done more for the technical thrill than to actually play the game on terribly limited hardware. We love seeing it done, whether the game is ported to a LEGO brick or a pair of earbuds. If you’re doing your own silly port, don’t hesitate to notify the tipsline—just make sure it’s one we haven’t seen before.

Inside SKALA: How Chernobyl’s Reactor Was Actually Controlled

March 3, 2026 by Maya Posch 3 Comments

Entering SKALA codes during RBMK operation. (Credit: Pripyat-Film studio)

Running a nuclear power plant isn’t an easy task, even with the level of automation available to a 1980s Soviet RBMK reactor. In their continuing efforts to build a full-sized, functional replica of an RBMK control room as at the Chornobyl Nuclear Power Plant – retired in the early 2000s – the [Chornobyl Family] channel has now moved on to the SKALA system.

Previously we saw how they replicated the visually very striking control panel for the reactor core, with its many buttons and status lights. SKALA is essentially the industrial control system, with multiple V-3M processor racks (‘frames’), each with 20k 24-bit words of RAM. Although less powerful than a PDP-11, its task was to gather all the sensor information and process them in real-time, which was done in dedicated racks.

Output from SKALA’s DREG program were also the last messages from the doomed #4 reactor. Unfortunately an industrial control system can only do so much if its operators have opted to disable every single safety feature. By the time the accident unfolded, the hardware was unable to even keep up with the rapid changes, and not all sensor information could even be recorded on the high-speed drum printer or RTA-80 teletypes, leaving gaps in our knowledge of the accident.

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Designing A Pen Clip That Never Bends Out Of Shape

March 3, 2026 by Lewin Day 7 Comments

If you’ve ever used a ballpoint pen with a clip on the top, you’ve probably noticed they bend pretty easily. The clip relies on you only bending it a small amount to clip it on to things; bend it too far, and it ends up permanently deformed. [Craighill] decided to develop a pen clip that didn’t suffer this ugly malady.

The wire clip design easily opens wide because the spring wire is not actually deforming much at all. Credit: YouTube video, via screenshot

The problem with regular pen clips comes down to simple materials science. Bend the steel clip a little bit, and the stress in the material remains below the elastic limit—so it springs back to its original shape. Push it too far, though, and you’ll end up getting into the plastic deformation region, where you’ve applied so much stress that the material is permanently deformed.

[Craighill] noted this problem, and contemplated whether a better type of clip was possible. An exploration of carabiner clips served to highlight possible solutions. Some carabiners using elastically-deformed closures that faced the same problem, while others used more complicated spring closures or a nifty bent-wire design. This latter solution seemed perfect for building a non-deforming pen clip. The bent wire is effectively a small spring, which allows it to act as a clip to hold the pen on to something. However, it’s also able to freely rotate out from the pen body, limiting the amount of actual stress put on the material itself, which stops it entering the plastic deformation region that would ruin it.

It’s some neat materials science combined with a pleasant bit of inventing, which we love to see. Sometimes there is joy to be had in contemplating and improving even the simplest of things. Video after the break.

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Exploring Security Vulnerabilities In A Cheapo WiFi Extender

March 3, 2026 by Maya Posch 7 Comments

If all you want is just a basic WiFi extender that gets some level of network connectivity to remote parts of your domicile, then it might be tempting to get some of those $5, 300 Mbit extenders off Temu as [Low Level] recently did for a security audit. Naturally, as he shows in the subsequent analysis of its firmware, you really don’t want to stick this thing into your LAN. In this context it is also worrying that the product page claims that over a 100,000 of these have been sold.

Starting the security audit is using $(reboot) as the WiFi password, just to see whether the firmware directly uses this value in a shell without sanitizing. Shockingly, this soft-bricks the device with an infinite reboot loop until a factory reset is performed by long-pressing the reset button. Amusingly, after this the welcome page changed to the ‘Breed web recovery console’ interface, in Chinese.

Here we also see that it uses a Qualcomm Atheros QCA953X SoC, which incidentally is OpenWRT compatible. On this new page you can perform a ‘firmware backup’, making it easy to dump and reverse-engineer the firmware in Ghidra. Based on this code it was easy to determine that full remote access to these devices was available due to a complete lack of sanitization, proving once again that a lack of input sanitization is still the #1 security risk.

In the video it’s explained that it was tried to find and contact a manufacturer about these security issues, but this proved to be basically impossible. This leaves probably thousands of these vulnerable devices scattered around on networks, but on the bright side they could be nice targets for OpenWRT and custom firmware development.

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The Perfect Cheat’s Racing Bicycle

March 3, 2026 by Jenny List 17 Comments

One of the ongoing rumors and scandals in professional cycle sport concerns “motor doping” — the practice of concealing an electric motor in a bicycle to provide the rider with an unfair advantage. It’s investigated in a video from [Global Cycling Network], in which they talk about the background and then prove its possible by creating a motor doped racing bike.

To do this they’ve recruited a couple of recent graduate engineers, who get to work in a way most of us would be familiar with: prototyping with a set of 18650 cells, some electronics, and electromagnets. It uses what they call a “Magic wheel”, which features magnets embedded in its rim that engage with hidden electromagnets. It gives somewhere just under 20 W boost, which doesn’t sound much, but could deliver those crucial extra seconds in a race.

Perhaps the most interesting part is the section which looks at the history of motor doping with some notable cases mentioned, and the steps taken by cycling competition authorities to detect it. They use infra-red cameras, magnetometers, backscatter detectors, and even X-ray machines, but even these haven’t killed persistent rumors in the sport. It’s a fascinating video we’ve placed below the break, and we thank [Seb] for the tip. Meanwhile the two lads who made the bike are looking for a job, so if any Hackaday readers are hiring, drop them a line.

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