Why Do We Love Weird Old Tech?

One of our newer writers, [Tyler August], recently wrote a love letter to plasma TV technology. Sitting between the ubiquitous LCD and the vanishing CRT, the plasma TV had its moment in the sun, but never became quite as popular as either of the other display techs, for all sorts of reasons. By all means, go read his article if you’re interested in the details. I’ll freely admit that it had me thinking that I needed a plasma TV.

I don’t, of course. But why do I, and probably a bunch of you out there, like old and/or odd tech? Take [Tyler]’s plasma fetish, for instance, or many people’s love for VFD or nixie tube displays. At Supercon, a number of people had hit up Apex Electronics, a local surplus store, and came away with some sweet old LED character displays. And I’ll admit to having two handfuls of these displays in my to-hack-on drawer that I bought surplus a decade ago because they’re so cute.

It’s not nostalgia. [Tyler] never had a plasma growing up, and those LED displays were already obsolete before the gang of folks who had bought them were even born. And it’s not simply that it’s old junk – the objects of our desire were mostly all reasonably fancy tech back in their day. And I think that’s part of the key.

My theory is that, as time and tech progresses, we see these truly amazing new developments become commonplace, and get forgotten by virtue of their ever-presence. For a while, having a glowing character display in your car stereo would have been truly futuristic, and then when the VFD went mainstream, it kind of faded into our ambient technological background noise. But now that we all have high-res entertainment consoles in our cars, which are frankly basically just a cheap tablet computer (see what I did there?), the VFD becomes an object of wonder again because it’s rare.

Which is not to say that LCD displays are anything short of amazing. Count up the rows and columns of pixels, and multiply by three for RGB, and that’s how many nanoscale ITO traces there are on the screen of even the cheapest display these days. But we take it for granted because we are surrounded by cheap screens.

I think we like older, odder tech because we see it more easily for the wonder that it is because it’s no longer commonplace. But that doesn’t mean that our current “boring” tech is any less impressive. Maybe the moral of the story is to try to approach and appreciate what we’ve got now with new eyes. Pretend you’re coming in from the future and finding this “old” gear. Maybe try to figure out how it must have worked.

2025 Component Abuse Challenge: Light An LED With Nothing

Should you spend some time around the less scientifically informed parts of the internet, it’s easy to find “Free power” stories. Usually they’re some form of perpetual motion machine flying in the face of the laws of conservation of energy, but that’s not to say that there is no free power.

The power just has to come from somewhere, and if you’re not paying for it there’s the bonus. [joekutz] has just such a project, lighting up LEDs with no power source or other active electronics.

Of course, he’s not discovered perpetual motion. Rather, while an LED normally requires a bit of current to light up properly, it seems many will produce a tiny amount of light on almost nothing. Ambient electromagnetic fields are enough, and it’s this effect that’s under investigation. Using a phone camera and a magnifier as a light detector he’s able to observe the feeble glow as the device is exposed to ambient fields.

In effect this is using the LED as the very simplest form of radio receiver, a crystal set with no headphone and only the leads, some wires, and high value resistors as an antenna. The LED is after all a diode, and it can thus perform as a rectifier. We like the demonstration even if we can’t quite see an application for it.

While we’re no longer taking new entries for the 2025 Component Abuse Challenge, we’ve still got plenty of creative hacks from the competition to show off. We’re currently tabulating the votes, and will announce the winners of this particularly lively challenge soon.

A hand holding the circuit in its active state

2025 Component Abuse Challenge: A Self-Charging LED Flasher By Burkhard Kainka

[Tito] entered a Self-Charging LED Flasher into the Component Abuse Challenge. It’s a simple re-build of a design by the unstoppable [Burkhard Kainka], and while [Tito] doesn’t explain its workings in detail, it’s a clever experiment in minimalism, and a bit of a head-scratcher at the same time.

You press a button and an LED flashes.  But there is no battery, so how does it work? Maybe the schematic to the right here will help. Or does it confound? Look at it yourself before reading on and see if you can figure out how it works.

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Chicken Squisher 3000

Chicken Squisher 3000: Squish-Proof Security

Keeping chickens in predator-prone areas demands serious fortifications, but even the most robust coop can become a hassle without automation. That’s where [lcamtuf] steps in with his Chicken Squisher 3000, a clever DIY automatic door mechanism that opens and closes based on ambient light levels.

The chicken coop he previously built did not include a mechanism to automatically close the inner door at night, meaning that arrangements would have to be made should [lcamtuf] want to leave town for a couple of days. Not wanting to go with a commercial option for this door as that would require a good deal of modifications to the original door setup, the Chicken Squisher 3000 adds minimal parts to the existing door to now open and close the door at dawn and dusk.

Using a 12 V DC motor with a gear reduction, he was able to generate more than enough torque to open and close the thick wooden door. Instead of a complex geared rack and pinion setup, [lcamtuf] has the motor mounted to a smooth rod that then applies force across the swing of the door attached with a rod end bearing. Driving the door’s automation is an AVR16DD14 microcontroller which is used to read the NSL-A6009 light sensor. [lcamtuf] uses a DRV8231 motor driver for controlling power going to that 12 V motor with the added benefit of being able to adjust stall torque to dial in a value strong enough to overcome the wooden door’s friction, but weak enough to not endanger any of his birds. There are also buttons on the metal enclosure used to override the light sensor should he want to override it manually.

Thanks, [lcamtuf], for sending in your latest weekend project; we love the resourcefulness of using just a handful of cheap parts to make a robust solution for your coop. If you haven’t seen them yet, be sure to check out some of our other chicken coop door hacks featured before.

Smart Bulbs Are Turning Into Motion Sensors

If you’ve got an existing smart home rig, motion sensors can be a useful addition to your setup. You can use them for all kinds of things, from turning on lights when you enter a room, to shutting off HVAC systems when an area is unoccupied. Typically, you’d add dedicated motion sensors to your smart home to achieve this. But what if your existing smart light bulbs could act as the motion sensors instead?

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On 3D Scanners And Giving Kinects A New Purpose In Life

The concept of a 3D scanner can seem rather simple in theory: simply point a camera at the physical object you wish to scan in, rotate around the object to capture all angles and stitch it together into a 3D model along with textures created from the same photos. This photogrammetry application is definitely viable, but also limited in the sense that you’re relying on inferring three-dimensional parameters from a set of 2D images and rely on suitable lighting.

To get more detailed depth information from a scene you’d need to perform direct measurements, which can be done physically or through e.g. time-of-flight (ToF) measurements. Since contact-free ways of measurements tend to be often preferred, ToF makes a lot of sense, but comes with the disadvantage of measuring of only a single spot at a time. When the target is actively moving, you can fall back on photogrammetry or use an approach called structured-light (SL) scanning.

SL is what consumer electronics like the Microsoft Kinect popularized, using the combination of a visible and near-infrared (NIR) camera to record a pattern projected onto the subject, which is similar to how e.g. face-based login systems like Apple’s Face ID work. Considering how often Kinects have been used for generic purpose 3D scanners, this raises many questions regarding today’s crop of consumer 3D scanners, such as whether they’re all just basically Kinect-clones.

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This Soviet-Style Clock Uses Homemade Nixie Tubes And Glowing Logic

The Neon glow of a Nixie tube makes for an attractive clock, but that’s not enough neon for some people. [Changliang Li] is apparently one of those people, because he’s using soviet-era cold-cathode tubes as the logic for his “Soviet-Era Style Clock”

Aside from the nixies for display, the key component you see working in this beautiful machine are the MTX-90 cold cathode thyratrons, which look rather like neon tubes in action. That’s because they essentially are, just with an extra trigger electrode (that this circuit doesn’t use). The neon tubes are combined into a loop counter, which translates the 50 Hz mains circuit in to seconds, minutes, and hours. The circuit is not original to this project, and indeed was once common to electronics books. The version used in this project is credited to [PA3FWM].

The Nixie tubes are new-made by [Sadudu] of iNixie labs, and we get a fascinating look in how they are made. (Tubemaking starts at around 1:37 in the video below.) It looks like a fiber laser is used to cut out glow elements for the tube, which is then encapsulated on a device which appears to be based around a lathe.

The cold-cathode tubes used as logic rely on ambient light or background radiation to start reliably, since the trigger electrode is left floating. In order to ensure reliable switching from the thyratrons, [Changliang Li] includes a surplus smoke detector source to ensure sufficient ionization. (The video seems to imply the MTX-90 was seeded with radioisotopes that have since decayed, but we could find no evidence for this claim. Comment if you know more.)

The end result is attractive and rather hypnotic. (Jump to 3:37 to see the clock in action.) If you want to know more about this sort of use for neon lamps (and the Soviet MTX-90) we featured a deeper dive a while back.

Thanks to [Changliang Li] for the incandescent tip. If one of your bright ideas has had a glow up into a project, don’t hesitate to share it on our tips line.

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