The History Of The World’s First Planetarium

May 6, 2024 by Al Williams 14 Comments

It shouldn’t be a surprise that the idea of a planetarium originated with an electrical engineer, [Oskar von Miller] from the Deutsches Museum in Munich. According to [Allison Marsh] in IEEE Spectrum, he thought about the invention in 1912 as a way to demonstrate astronomical principles to the general public. While it seems obvious today that you can project the night sky onto a dome, it was a novel thought in 1912. So novel that the Carl Zeiss company first told [von Miller] to take a hike. But they eventually reconsidered and built the first planetarium, the Model I.

The engineer for Zeiss was a mechanical engineer by the name of [Walther Bauersfeld]. He was familiar with mechanical devices — orreries — that tracked the motion of the stars and planets. The goal was to translate those movements into a moving projection of light.

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A diagram from the article, showing the router being used in a car for streaming media to multiple portable devices at once

A Portable DLNA Server Hack Helps You Tame OpenWRT

May 5, 2024 by Arya Voronova 12 Comments

A good amount of hacks can be done with off-the-shelf hardware – what’s more, it’s usually available all over the world, which means your hacks are easier to build for others, too. Say, you’ve built something around a commonly available portable router, through the magic of open-source software. How do you make the fruits of your labour easy to install for your friends and blog readers? Well, you might want to learn a thing or two from [Albert], who shows us a portable DLNA server built around a GL-MT300N-V2 pocket router.

[Albert]’s blog post is a tutorial on setting it up, with a pre-compiled binary image you can flash onto your router. Flash it, prepare a flash drive with your media files, connect to the WiFi network created by the router, run the VLC player app, and your media library is with you wherever you go.

Now, a binary image is good, but are you wondering how it was made, and how you could achieve similar levels of user-friendliness in your project? Of course, here’s the GitHub repository with OpenWRT configuration files used to build this image, and build instructions are right there in the README. If you ever needed a reference on how to make commonly available OpenWRT devices do your bidding automagically, this is it.

This is an elegant solution to build an portable DLNA server that’s always with you on long rides, and, think of it, it handily beats a typical commercialized alternative, at a lower cost. Want software upgrades? Minor improvements and fixes? Security patches? Everything is under your control, and thanks to the open-source nature of this project, you have a template to follow. There won’t always be a perfectly suited piece of hardware on the market, of course, as this elegant dual-drive Pi-based NAS build will attest.

Poking Atomic Nuclei With Lasers For Atomic Clocks And Energy Storage

May 5, 2024 by Maya Posch 5 Comments

Although most people are probably familiar with the different energy levels that the electron shells of atoms can be in and how electrons shedding excess energy as they return to a lower state emit for example photons, the protons and neutrons in atomic nuclei can also occupy an excited state. This nuclear isomer (metastable) state is a big part of radioactive decay chains, but can also be induced externally. The trick lies in hitting the right excitation wavelength and being able to detect the nuclear transition, something which researchers at the Technical University of Wien have now demonstrated for thorium-229.

The findings by [J.Tiedau] and colleagues were published in Physical Review Letters, describing the use of a vacuum-ultraviolet (VUV) laser setup to excite Th-229 into an isomer state. This isotope was chosen for its low-energy isomeric state, with the atoms embedded in a CaF₂ crystal lattice. By trying out various laser wavelengths and scanning for the signature of the decay event they eventually detected the signal, which raises the possibility of using this method for applications like new generations of much more precise atomic clocks. It also provides useful insights into nuclear isomers as it pertains to tantalizing applications like high-density energy storage.

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Hackaday Links: May 5, 2024

May 5, 2024 by Dan Maloney 16 Comments

It may be hard to believe, but BASIC turned 60 this week. Opinions about the computer language vary, of course, but one thing everyone can agree on is that Professors Kemeny and Kurtz really stretched things with the acronym: “Beginner’s All-Purpose Symbolic Instruction Code” is pretty tortured, after all. BASIC seems to be the one language it’s universally cool to hate, at least in its current incarnations like Visual Basic and VBA. But back in 1964, the idea that you could plunk someone down in front of a terminal, or more likely a teletype, and have them bang out a working “Hello, world!” program with just a few minutes of instruction was pretty revolutionary. Yeah, line numbers and GOTO statements encouraged spaghetti code and engrained bad programming habits, but at least it got people coding. And perhaps most importantly, it served as a “gateway drug” into the culture for a lot of us. Many of us would have chosen other paths in life had it not been for those dopamine hits provided by getting that first BASIC program working. So happy birthday BASIC!

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This Windows Installer Installs Linux

May 5, 2024 by Jenny List 15 Comments

It may be a very long time since some readers have installed a copy of Windows, but it appears at one point during the installation there’s a step that asks you which OS version you would like to install. Normally this is populated by whichever Windows flavours come on the install medium, but [Naman Sood] has other ideas. How about a Windows installer with Alpine Linux as one of the choices? Sounds good to us.

You can see it in action in the video below the break. Indeed Alpine Linux appears as one of the choices, followed by the normal Windows licence accept screen featuring the GPL instead of any MS text. The rest of the installer talks about installing Windows, but we can forgive it not expecting a Linux install instead.

So, the question we’re all asking is: how is it done? The answer lies in a WIM file, a stock Windows image which the installer unpacks onto your hard drive. The Linux distro needs to be installable onto an NTFS root partition, and to make it installable there’s a trick involving the Windows pre-installation environment.

This is an amusing hack, but the guide admits it’s fragile and perhaps not the most useful. Even so, the sight of Linux in a Windows installer has to be worth it.

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Building A Rocket Engine From Scratch

May 5, 2024 by Al Williams 14 Comments

There is a reason building a rocket engine is harder than most things you want to build. If you are building, say, a car, your goal is to not have it explode. If you are building a bomb, you want that to explode. But a rocket engine needs to explode just enough and not a bit more. That’s tough, as [Ryan Kuhn] discovered. He’s behind ABL’s E2 rocket, a LOX/kerosene engine for small vehicle launches. You can catch a video of the engine’s qualification tests below.

[Ryan] shares many of the problems encountered from many problems, each requiring finetuning of the design. True, there are plenty of publicly available NASA documents about what works and doesn’t work for rocket engines, but that can only take you so far. You can’t learn to bowl by reading about bowling, and you can’t design a successful rocket on paper just by reading about what others have done.

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A beehive sits on bricks with an outdoor-rated box full of electronics to monitor the hive.

Hive Monitor Is The Bee’s Knees

May 5, 2024 by Kristina Panos 11 Comments

Beekeeping is quite the rewarding hobby. There’s delicious honey and useful wax to be had, plus you get the honor of knowing that you’re helping to keep the bee population surviving and thriving. [Ben Brooks] likes to keep tabs on the hive, but doesn’t like the idea of opening it up more often than necessary. After a couple of beekeeping rodeos, [Ben] decided to build his own tracker to get reports on the health and the activity of the hive through Home Assistant.

This hive tracker features a light sensor, a temperature sensor, and three strain gauges to measure the weight. There would be four, but a mouse decided to take a bite of the wires in the most nightmarish place to repair.

Everything runs off of an ESP32, and there’s an external antenna involved because the hive is nearly out of Wi-Fi range. The strain gauges are the affordable bathroom-scale type, and [Ben] has extras for if and when the number of hives goes up.

We like the combination of hard work and simplicity going on here — [Ben] milled and drilled the PCB himself, and used phone plugs to connect the temperature and weight sensors. Unfortunately, the plugs make the strain gauges a little finicky, so [Ben] says he would probably use screw terminals next time, or might be soldering the wires sooner rather than later. Consider this one a work in progress, and keep watching for updates as [Ben] works out the kinks.

Interested in beekeeping, but don’t want to build a traditional hive? Check out this beehive in a bottle.