You Too Can Do The Franck-Hertz Experiment

March 15, 2025 by 5 Comments

We talk about quantum states — that is, something can be at one of several discrete values but not in between. For example, a binary digit can be a 1 or a 0, but not 0.3 or 0.5. Atoms have quantum states, but how do we know that? That’s what the Franck-Hertz experiment demonstrates, and [stoppi] shows you how to replicate that famous experiment yourself.

You might need to translate the web page if your German isn’t up to speed, but there’s also a video you can watch below. The basic idea is simple. A gas-filled tube sees a large voltage across the cathode and grid. A smaller voltage connects to the grid and anode. If you increase the grid voltage, you might expect the anode current to increase linearly. However, that doesn’t happen. Instead, you’ll observe dips in the anode current.

When electrons reach a certain energy they excite the gas in the tube. This robs them of the energy they need to overcome the grid/anode voltage, which explains the dips. As the energy increases, the current will again start to rise until it manages to excite the gas to the next quantum level, at which point another dip will occur.

Why not build a whole lab? Quantum stuff, at a certain level, is weird, but this experiment seems understandable enough.

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Bar of conductive filament with leds and a battery

Putting Conductive TPU To The Test

March 15, 2025 by 3 Comments

Ever pried apart an LCD? If so, you’ve likely stumbled at the unassuming zebra strip — the pliable connector that makes bridging PCB pads to glass traces look effortless. [Chuck] recently set out to test if he could hack together his own zebra strip using conductive TPU and a 3D printer.

[Chuck] started by printing alternating bands of conductive and non-conductive TPU, aiming to mimic the compressible, striped conductor. Despite careful tuning and slow prints, the results were mixed to say the least. The conductive TPU measured a whopping 16 megaohms, barely touching the definition of conductivity! LEDs stayed dark, multimeters sulked, and frustration mounted. Not one to give up, [Chuck] took to his trusty Proto-pasta conductive PLA, and got bright, blinky success. It left no room for flexibility, though.

It would appear that conductive TPU still isn’t quite ready for prime time in fine-pitch interconnects. But if you find a better filament – or fancy prototyping your own zebra strip – jump in! We’d love to hear about your attempts in the comments.

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My Scammer Girlfriend: Baiting A Romance Fraudster

March 15, 2025 by 21 Comments

Nobody likes spam messages, but some of them contain rather fascinating scams. Case in point, [Ben Tasker] recently got a few romance scam emails that made him decide to take a poke at the scam behind these messages. This particular scam tries to draw in marks with an attached photo (pilfered from Facebook) and fake personal details. Naturally, contacting scammers is a bad idea, and you should never provide them with any personal information if you decide to have some ‘fun’.

The games begin once you contact them via the listed email address, as they’re all sent from hacked/spoofed email accounts. After this you have to wait for the scammers to return to the campaign on their monthly cycle, so give it a few weeks. Analyzing image metadata provides some clues (e.g. the FBMD prefix in IPTC tags set by Meta, as well as timezone info). The IP address from the email headers pointed to a VPN being used, so no easy solution here.

After establishing contact, the scammers try to coax the mark into ‘helping’ them move to their country, with Skype out-call numbers received on [Ben]’s burner phone that seem designed to add to the realism. Then ‘disaster’ strikes and the mark is asked to transfer a lot of money to help their new ‘love’. Naturally, [Ben] wasn’t a gullible mark, and set up a few traps, including a custom domain and website that’d log any visitor (i.e. the scammer).

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Probably The Simplest Sequencing Synth

March 15, 2025 by 31 Comments

With inexpensive microntrollers capable of the most impressive feats of sound synthesis, it’s not so often we see projects that return to an earlier style of electronic music project. The 1-bit synth from [Electroagenda] takes us firmly into that territory, employing that most trusty of circuits, a 555.

It’s a time-honored circuit, a 555 provides a note clock that drives a 4017 that functions as a sequencer. This switches in a set of voltage dividers, which in turn control another 555 oscillator that produces the notes. It’s a fun toy straight from the 1970s, right down to the protoboard and hookup wire construction. There’s a demo video with some lovely beeps below, and we think most of you should have what it takes to make your own.

If you’re seeking more inspiration, may we introduce you to our Logic Noise series?

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Make Your Cheap Thermal Camera Into A Microscope

March 14, 2025 by 17 Comments

[Project 326] has a cheap thermal camera that plugs into a smart phone. Sure they are handy, but what if you could hack one into a microscope with a resolution measured in microns? It is easier than you might think and you can see how in the video below.

Of course, microscopes need lenses, but glass doesn’t usually pass IR very well. This calls for lenses made of exotic material like germanium. One germanium lens gives some magnification. However, using a 3D printed holder, three lenses are in play, and the results are impressive.

The resolution is good enough to see the turns of wire in an incandescent light bulb. A decapsulated power transistor was interesting to view, too. Imaging heat at that much resolution gives you a lot of information. At the end, he teases that using first surface mirrors, he may show how to build an IR telescope as well.

Presumably, this will work with just about any IR camera if you adapt the lens holder. The unit in the video is a UNI-T UTi-260M. So when he says he spent about $35 on the build, that’s not including the $400 or so camera module.

IR imaging can pull off some amazing tricks, like looking inside an IC. If the thermal camera used in the video isn’t to your liking, there are plenty of others out there.

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Building A Ten-Hundred Key Computer Word-Giving Thing

March 14, 2025 by 17 Comments

From the styling of this article’s title, some might assume that the Hackaday editors are asleep at the switch this fine day. While that might be true — it’s not our turn to watch them — others will recognize this tortured phrasing as one way to use the 1,000 most commonly used words in the English language to describe a difficult technical project, such as [Attoparsec]’s enormous and enormously impractical ten-hundred word keyboard.

While the scale of this build is overwhelming enough, the fact that each key delivers a full word rather than a single character kind of throws the whole keyboard concept out the window. The 60×17 matrix supports the 1,000 most common English words along with 20 modifier keys, which allow a little bit of cheating on the 1-kiloword dictionary by letting you pluralize a word or turn it into an adjective or adverb. Added complexity comes from the practical limits of PCB fabrication, which forces the use of smaller (but still quite large) PCBs that are connected together. Luckily, [Attoparsec] was able to fit the whole thing on five identical PCBs, which were linked together with card-edge connectors.

The list of pain points on this six-month project is long, and the video below covers them all in detail. What really stood out to us, though, was the effort [Attoparsec] put into the keycaps. Rather than 3D printing his own, he used dye sublimation to label blank keycaps with the 1,000 words. That might sound simple, but he had to go through a lot of trial and error before getting a process that worked, and the results are quite nice. Another problem was keeping the key switches aligned while soldering, which was solved with a 3D printed jig. We also appreciate the custom case to keep this keyboard intact while traveling; we’re going to keep that build-your-own road case service in mind for future projects.

This mega-keyboard is a significant escalation from [Attoparsec]’s previous large keyboard project. The results are pretty ridiculous and impractical, but that’s just making us love it more. The abundance of tips and tricks for managing a physically expansive project are just icing on the cake.

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