Building A DIY Muon Tomography Device For About $100

Muon tomography, or muography, is the practice of using muons generated by cosmic rays interacting with Earth’s atmosphere to image structures on Earth’s surface, akin to producing an X-ray. In lieu of spending a fair bit of money on dedicated muon detectors, you can also hack such a device together with two Geiger-Müller tubes and related circuitry for about $100 or whatever you can source the components for.

The reason for having two Geiger-Müller tubes is to filter out other much more prevalent sources of ionizing radiation that we’re practically bathed in every second. Helped by a sheet of lead between both tubes, only a signal occurring at the same time from both tubes should be a muon. Specially cosmic ray muons, as these have significantly more kinetic energy that allows them to pass through both tubes. As a simple check it’s helpful to know that most of these muons will come from the direction of the sky.

The author of the article tested this cobbled-together detector in an old gold mine. Once there the presence of more rock, and fewer muons, was easily detected, as well as a surge in muons indicating a nearby void from a mine shaft. While not a fast or super-easy way to image structures, it’s hard to beat for the price and the hours of fun you can have while spelunking.

A bright yellow crew cab pickup is on an unpaved area with snow-capped mountains in the distance. In its bed is a matching camper shell which is somewhat trapezoidal with a smaller semicircular section that can pull out to lengthen the sleeping space of the camper. At the top of the image it says, "Sleeps Two!" with an arrow pointing to the camper shell.

Want A Truck With A Short Bed And A Long Camper Shell?

Camper shells are a time-honored piece of truck gear, but with modern trucks having increasingly vestigial beds, the length of your overnight abode has increasingly shrunk as well. To combat this problem, [Ed’s Garage] built a camper shell that extends once you’ve arrived at your campsite.

[Ed] wanted to keep things relatively low profile while still tall enough to sit up in for convenience, leading to a small bit of the shell peeking over the truck’s roof. To keep the cold Canadian winter out, attention was paid to proper weather sealing around the sliding portion of the shell so that it stays warm and dry inside.

While this would work on any truck, the mains power plugs in the bed of some modern trucks mean that certain glamping conveniences like a heater and projector can be easily powered while you’re in camp. We get to see the camper shell in action at the end of the video where the pros and cons of having your sleeping space also being your storage while en route become apparent.

If you’re looking for something a little less conventional for your camping experience, how about this solar camper or this retro bike camper?

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Too Smooth: Football And The “KnuckleBall” Problem

Picture a football (soccer ball) in your head and you probably see the cartoon ideal—a roughly spherical shape made with polygonal patches that are sewn together, usually in a familiar pattern of black and white. A great many balls were made along these lines for a great many decades.

Eventually, though, technology moved on. Footballs got rounder, smoother, and more colorful. This was seen as a good thing, with each new international competition bringing shiny new designs with ever-greater performance. That was, until things went too far, and the new balls changed the game. Thus was borne the “knuckleball” phenomenon.

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A dark warehouse contains a number of large blocky objects. A Tesla Model 3 sedan sits in the center with flames underneath and curling up the side away from the camera. A firefighter on the left side attempts to put out the fire with a fire hose.

UL Investigates The Best Way To Fight EV Fires

While electric vehicles (EVs) are generally less likely to catch fire than their internal combustion counterparts, it does still happen, and firefighters need to be ready. Accordingly, the UL Research Institute is working with reverse engineering experts Munro & Associates to characterize EV fires and find the best way to fight them.

There is currently some debate in the firefighting community over whether it’s better to try to put an EV battery fire out with water or to just let it burn. Research like this means the decision doesn’t have to fall on only anecdotal evidence. Anyone who’s worked in a lab will recognize the mix of exceedingly expensive equipment next to the borderline sketchy rigged up hacks on display, in this case the super nice thermal imagers and a “turkey burner on steroids.” The video goes through some discussion of the previous results with a Chevy Bolt, Hyundai Kona, Ford Mustang Mach E, and then we get to see them light up a Tesla Model 3. This is definitely one you shouldn’t try at home!

While the massive battery banks in modern EVs can pose unique challenges in the event of an accident, that doesn’t mean they can’t be repurposed to backup your own home.

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Hackaday Europe 2025: Workshops And More Speakers

We’re proud to announce the last round of speakers, as well as the two workshops that we’ll be running at 2025 Hackaday Europe in Berlin on March 15th and 16th — and Friday night the 14th, if you’re already in town.

The last two years that we’ve done Hackaday Europe in Berlin have been awesome, and this year promises to keep up the tradition. We can’t wait to get our hands on the crazy selection of SAO badge addons that are going to be in each and every schwag bag.

Tickets for the event itself are going fast, but the workshop tickets that go on sale at 8:00 AM PST sell out even faster. And you need the one to enjoy the other, so get your tickets now!

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New Camera Does Realtime Holographic Capture, No Coherent Light Required

Holography is about capturing 3D data from a scene, and being able to reconstruct that scene — preferably in high fidelity. Holography is not a new idea, but engaging in it is not exactly a point-and-shoot affair. One needs coherent light for a start, and it generally only gets touchier from there. But now researchers describe a new kind of holographic camera that can capture a scene better and faster than ever. How much better? The camera goes from scene capture to reconstructed output in under 30 milliseconds, and does it using plain old incoherent light.

The camera and liquid lens is tiny. Together with the computation back end, they can make a holographic capture of a scene in under 30 milliseconds.

The new camera is a two-part affair: acquisition, and calculation. Acquisition consists of a camera with a custom electrically-driven liquid lens design that captures a focal stack of a scene within 15 ms. The back end is a deep learning neural network system (FS-Net) which accepts the camera data and computes a high-fidelity RGB hologram of the scene in about 13 ms.  How good are the results? They beat other methods, and reconstruction of the scene using the data looks really, really good.

One might wonder what makes this different from, say, a 3D scene captured by a stereoscopic camera, or with an RGB depth camera (like the now-discontinued Intel RealSense). Those methods capture 2D imagery from a single perspective, combined with depth data to give an understanding of a scene’s physical layout.

Holography by contrast captures a scene’s wavefront information, which is to say it captures not just where light is coming from, but how it bends and interferes. This information can be used to optically reconstruct a scene in a way data from other sources cannot; for example allowing one to shift perspective and focus.

Being able to capture holographic data in such a way significantly lowers the bar for development and experimentation in holography — something that’s traditionally been tricky to pull off for the home gamer.