A photo of the camera.

F/0.38 Camera Lens Made With Oil Immersion Microscope Objective

Over on YouTube [Applied Science] shows us how to make an f/0.38 camera lens using an oil immersion microscope objective.

The f-number of a lens indicates how well it will perform in low-light. To calculate the f-number you divide the focal length by the diameter of the aperture. A common f-number is f/1.4 which is generally considered “fast”.

We are told the fastest commercial lens ever used had f/0.7 and was used by Stanley Kubrick to shoot the film Barry Lyndon which was recorded only with candle light.

A microscope objective is a crucial lens that gathers and magnifies light to form an image. It plays a key role in determining the quality and clarity of the final magnified image produced by a microscope.

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2025 Component Abuse Challenge: Boosting Voltage With Just A Wire

Switching power supplies are familiar to Hackaday readers, whether they have a fairly conventional transformer, are a buck, a boost, or a flyback design. There’s nearly always an inductor involved, whose rapid change in magnetic flux is harnessed to do voltage magic. [Craig D] has made a switching voltage booster that doesn’t use an inductor, instead it’s using a length of conductor, and no, it’s not using the inductance of that conductor as a store of magnetic flux.

Instead it’s making clever use of reflected short pulses in a transmission line for its operation. Electronics students learn all about this in an experiment in which they fire pulses down a length of coax cable and observe their reflections on an oscilloscope, and his circuit is very similar but with careful selection of pulse timing. The idea is that instead of reflected pulses canceling out, they arrive back at the start of the conductor just in time to meet a pulse transition. This causes them to add rather than subtract, and the resulting higher voltage pulse sets off down the conductor again to repeat the process. We can understand the description, but this is evidently one to sit down at the bench and experiment with to fully get to grips with.

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Hackaday Podcast Episode 342: Poopless Prints, Radio In Your Fillings, And One Hyperspectral Pixel At A Time

It was Elliot and Dan on the podcast today, taking a look at the best the week had to offer in terms of your hacks. We started with surprising news about the rapidly approaching Supercon keynote; no spoilers, but Star Trek fans such as we who don’t have tickets will be greatly disappointed.

Elliot waxed on about taking the poop out of your prints (not pants), Dan got into a camera that adds a dimension to its images, and we both delighted in the inner workings of an air-powered squishy robot.

Questions? We’ve got plenty. Is it possible to take an X-ray without an X-ray tube? Or X-rays, for that matter? Did Lucille Ball crack a spy ring with her fillings? Is Algol set to take over the world? What’s inside a germanium transistor? How does a flipping fish say Happy Birthday? And how far down the Meshtastic rabbit hole did our own Tom Nardi fall? Tune in to find out the answers.

Download this free-range, cruelty-free MP3.

Continue reading “Hackaday Podcast Episode 342: Poopless Prints, Radio In Your Fillings, And One Hyperspectral Pixel At A Time”

DIY Telescope Uses Maker Tools

You’ve got a laser cutter. You’ve got a 3D printer. What do you make? [Ayushmaan45] suggests a telescope. The modest instrument isn’t going to do serious astronomy with only 8X worth of optics, but it would make a fine spyglass for a youngster.

The body is cut from MDF, and there are only a few 3D printed parts. The only other things you need are rubber bands and a pair of lenses. You don’t even need glue. We might have spray painted the inside of the scope black or used some black contact paper to cut down on reflections, although it probably wouldn’t make much difference.

Of course, depending on your lenses, you may have to make some changes. Or find new lenses, for that matter. We like that it doesn’t take any exotic parts. We also appreciate that it is easy for kids to take apart and put back together. It would be interesting to see how a motivated kid might alter the design, as well.

If a kid gets interested, you could move on to a more sophisticated telescope. Or maybe you’d prefer a nice microscope.

This Week In Security: F5, SonicWall, And The End Of Windows 10

F5 is unintentionally dabbling in releasing the source code behind their BIG-IP networking gear, announcing this week that an unknown threat actor had access to their internal vulnerability and code tracking systems. This security breach was discovered on August 9th, and in the time since, F5 has engaged with CrowdStrike, Mandiant, and NCC Group to review what happened.

So far it appears that the worst result is access to unreleased vulnerabilities in the F5 knowledge management system. This means that any unpatched vulnerabilities were effectively 0-days, though the latest set of patches for the BIG-IP system has fixed those flaws. There aren’t any reports of those vulnerabilities being exploited in the wild, and F5 has stated that none of the leaked vulnerabilities were critical or allowed for remote exploitation.

Slightly more worrying is that this access included the product development environment. The problem there isn’t particularly the leak of the source code — one of the covered projects is NGINX, which is already open source software. The real danger is that changes could have been surreptitiously added to those codebases. The fact that NGINX is Open Source goes a long way to alleviate that danger, and when combined with the security built into tools like git, it seems very unlikely that malicious code could be sneaked into the NGINX public code base. A thorough review of the rest of the F5 codebases has similarly come up negative, and so far it looks like the supply-chain bullet has been dodged. Continue reading “This Week In Security: F5, SonicWall, And The End Of Windows 10”

Site Of Secret 1950s Cold War Iceworm Project Rediscovered

The overall theme of the early part of the Cold War was that of subterfuge — with scientific missions often providing excellent cover for placing missiles right on the USSR’s doorstep. Recently NASA rediscovered Camp Century, while testing a airplane-based synthetic aperture radar instrument (UAVSAR) over Greenland. Although established on the surface in 1959 as a polar research site, and actually producing good science from e.g. ice core samples, beneath this benign surface was the secretive Project Iceworm.

By 1967 the base was forced to be abandoned due to shifting ice caps, which would eventually bury the site under over 30 meters of ice. Before that, the scientists would test out the PM-2A small modular reactor. It not only provided 2 MW of electrical power and heat to the base, but was itself subjected to various experiments. Alongside this public face, Project Iceworm sought to set up a network of mobile nuclear missile launch sites for Minuteman missiles. These would be located below the ice sheet, capable of surviving a first strike scenario by the USSR. A lack of Danish permission, among other complications, led to the project eventually being abandoned.

It was this base that popped up during the NASA scan of the ice bed. Although it was thought that the crushed remains would be safely entombed, it’s estimated that by the year 2100 global warming will have led to the site being exposed again, including the thousands of liters of diesel and tons of hazardous waste that were left behind back in 1967. The positive news here is probably that with this SAR instrument we can keep much better tabs on the condition of the site as the ice cap continues to grind it into a fine paste.


Top image: Camp Century in happier times. (Source: US Army, Wikimedia)

A New Golden Age Of Browser Games

Arguably, the golden age of browser gaming occurred in the 00s mostly revolving around Adobe Flash. This was an era with high creativity and a low barrier of entry, and also decentralized from gatekeeping app stores. Sadly, these times have passed us by as the security concerns around Flash led to its discontinuation and most casual gamers have migrated to the app store for their fix. But that doesn’t stop some from continuing to bring gaming to the browser, even if those games were never intended for it in the first place like this browser port of Celeste.

Celeste is an indie platformer where the player climbs a mysterious mountain while confronting her inner struggles. Originally meant for consoles and PC, a group of friends including [velzie], [bomberfish], and [Toshit] aka [r58Playz] took this as a challenge especially after seeing someone else’s half finished web port of this game. Most of the build revolves around WebAssembly (wasm) and around “cursed” .NET runtime hacks which also allow the port to run the community-made Everest mod loader. It uses a multithreaded and JIT compiling version of mono-wasm backported from .NET 10 to .NET 9 to maximize performance. The team actually first started by porting Terraria to the browser, and then moved on to this Celeste port from there.

The port of Celeste can be played here, and their port of Terraria is also available, although may not support a ton of Hackaday traffic so some patience is advised. There are also GitHub repositories for Celeste and Terraria as well.  With impressive ports of relatively modern games moving into the browser, perhaps we’re entering a new golden age of browser gaming; we’ve also seen things like Minecraft implemented in only HTML and CSS lately as well.