Nixie Clock Claims To Be Simplest Design

[Engineer2you] built a nixie tube clock and claims it is the simplest design. We felt like that was a challenge. In this design, the tubes are set up as a matrix with optoisolators on each row and column. With 60 segments, the matrix allows you to control it all with 16 bits. There are six columns, each corresponding to a digit. That means each row has 10 lines.

The Arduino code reads the clock and produces the output to the tubes fast enough that your eye perceives each digit as being always on, even though it isn’t.

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RF Shield Turns Arduino (And PC) Into Shortwave Radio

Microcontrollers tend to consume other kinds of electronics. A project you might once have done with a 555 now probably has a cheap microcontroller in it. Music synthesizers? RC controllers? Most likely, all microcontroller-based now. We always thought RF electronics would be immune to that, but the last decade or two has proven us wrong. Software-defined radio or SDR means you get the RF signal to digital as soon as possible and do everything else in software. If you want an introduction to SDR, Elektor now has an inexpensive RF shield for the Arduino. The Si5351-based board uses that oscillator IC to shift RF signals down to audio frequencies and then makes it available to the PC to do more processing.

The board is available alone or as part of a kit that includes a book. There’s also a series of Elektor articles about it. There’s also a review video from Elektor about the board in the video, below.

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Emergency Torch Runs Without Batteries

It’s always good to have a torch on hand for emergencies. Unfortunately, sometimes these torches can be forgotten, and wind up with dead batteries when you need them most. For those cases, this build from [techrallyofficial] is just the ticket.

Instead of a battery, the torch relies on a 1.5 farad supercapacitor to store energy. The body of the torch is constructed out of PVC pipe and fittings, and packs strong neodymium magnets inside. A coil of wire wrapped is formed around an old solder spool, which, when shaken past the magnets, generates a current. This is rectified with a series of diodes and charges the supercapacitor, powering the light.

It’s a classic design that is available commercially, but it’s one easily replicated in the home shop, too. It would make a great educational project, particularly as students would be left with a useful device to take home at the end of the lesson. We’ve seen others resurrect commercial builds with upgrades, too. Video after the break.

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This Servo Actuated Multimeter Does The Twist

This tip comes our way courtesy of [Elad Orbach], who’s been experimenting with a device that uses a servo to turn the function dial on a multimeter. It’s something you can put together in a few minutes with leftovers from the parts bin, and as you can see in the video after the break, the basic concept seems to be sound enough.

As to finding a practical reason for spinning the switch on your meter with a servo, that’s left largely as an exercise for the reader. [Elad] hints at the possibility of using such a setup to help automate repetitive testing, which we could see being useful especially in combination with a foot pedal that allows you to switch modes without having to put the probes down. The same basic idea could also be helpful as an assistive device for those who have difficulty grasping or limited dexterity.

Whether top of the line or bottom of the barrel, the multimeter is easily the hardware hacker’s most frequently used tool (beyond the screwdriver, perhaps). We’ve seen plenty of projects that try to graft additional features onto this common gadgets, though automation isn’t usually among them.

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A Crash Course In Thermodynamics For Electrical Engineers

It’s a simple fact that, in this universe at least, energy is always conserved. For the typical electronic system, this means that the energy put into the system must eventually leave the system. Typically, much of this energy will leave a system as heat, and managing this properly is key to building devices that don’t melt under load. It can be a daunting subject for the uninitiated, but never fear — Adam Zeloof delivered a talk at Supercon 2019 that’s a perfect crash course for beginners in thermodynamics.

Adam’s talk begins by driving home that central rule, that energy in equals energy out. It’s good to keep in the back of one’s mind at all times when designing circuits to avoid nasty, burning surprises. But it’s only the first lesson in a series of many, which serve to give the budding engineer an intuitive understanding of the principles of heat transfer. The aim of the talk is to avoid getting deep into the heavy underlying math, and instead provide simple tools for doing quick, useful approximations.

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It Ain’t Over ‘Til The Paperwork Is Done: Test Driving TiddlyWiki

Working on projects is fun. Documenting them is often not so much. However, if you want anyone to duplicate your work — or even just want to remember what you were doing a few years ago when something needs upgrading or repairing.

There’s a ton of ways to keep track of the details of your projects. We love seeing how things come together and of course we’re happy to suggest documenting on But sometimes, you just want to keep your own notes to yourself. There’s always a notebook, of course, but that seems kind of old fashioned. A lot of projects are on Wikis but you hate to stand up a web server and a Wiki instance just to keep notes. But what if you could have a local Wiki with minimal setup?

I recently came across TiddlyWiki and decided to take it for a spin. Join me after to break to see what it’s all about.

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Hackaday Podcast 054: Xenomorph Cookies, 101 Uses For Hot Glue, Rolling Robots, And A Clippy Computer

Hackaday editors Elliot Williams and Mike Szczys reflect on great hacks of the past few days. Strain relief is something every electronics geek encounters and there’s a spiffy way to make your hot-glue look like a factory connector. There’s something in the air and it seems to be recreating early computers. Did you know astronauts are baking cookies they’re forbidden to eat? And did you hear about the 3D printer that’s being fed oil from the deep fryer?

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Direct download (~60 MB)

Places to follow Hackaday podcasts:

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