A Brief History Of The Crazy Old 7-Segment Display

July 9, 2026 by Al Williams 12 Comments

How old is the seven-segment display? Surely it is a product of the 1970s. After all, calculators started showing up, and the height of junior high humor was plugging 7734 into your calculator and showing it to someone upside down. Of course, for it to go mainstream, maybe they really originated in the 1960s, but no earlier than that, right? Actually, no. Sure, the LED seven-segment display had to wait for LEDs. But the actual idea is much older than that.

The concept of building numbers from a small set of reusable segments predates LED displays by decades. In fact, the basic idea appears in patents from the early 1900s and may have roots in even older mechanical signs and printing techniques.

The history isn’t entirely straightforward. Unlike vacuum tubes or transistors, segmented displays evolved gradually through a series of practical ideas rather than one defining invention.

Blacking out the Eight

While looking into the history of segmented displays, I was reminded of something I’d seen years ago in retail stores: reusable price tags printed with rows of eights.

Rather than printing every possible price, the clerk simply used a marker to black out portions of each figure, transforming an 8 into whatever digit was needed. Cover a few strokes, and the eight becomes a three. Remove a different set, and it becomes a zero or a five. It was, in essence, a manual segmented display.

Finding the exact origin of these price tags is akin to finding out where Romans bought sponges. They were inexpensive commercial supplies, not the sort of products that historians carefully documented. My recollection is from the middle of the twentieth century, but the underlying concept is almost certainly older.

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Is Now The Time For Volumetric 3D Printing?

July 7, 2026 by Ian Bos 24 Comments

Of all innovations adopted by the maker community within the past couple of decades, one stands among the rest on top for anything regarding manufacturing. It goes without saying here at Hackaday how many projects have been reliant on using the technology to turn their ideas into reality. 3D printing has been a maker community invention and, in return, has expanded this hacky community into something that anyone with an imagination can get into. It also goes without saying that the layer-based tech imposes limits on what we can actually create: think overhangs and layer adhesion. However, there’s a possibility that a recent offshoot of this scrappy community has the power to eliminate some of these faults.

Volumetric additive manufacturing (VAM) is a young technology that has a similar start to many new tech toys, including the original SLA of the first 3D printers. That is expensive and completely stuck in the laboratory… Fortunately, that’s not where 3D printing as a whole stayed, as the RepRap project managed to bring the obscure technology to the hobbyists’ main stage. An entire group of people formed and spent countless hours until the useless pieces of poorly extruded plastic could form parts impossible to make with anything else. A cool quirk of history is that it likes to repeat: examples spur recreation, and this appears to be happening with the technology found within VAM printing.

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Ultra-Long Range Flights To Ease Australian Air Travel

July 6, 2026 by Zoe Skyforest 56 Comments

Pity the poor Australians. Isolated on a jagged hunk of land far from everywhere else, these industrious people have to take two-legged flights (or more) to reach a great many destinations in the northern hemisphere. It’s expensive, time consuming, and makes planning a trip a complete headache when wars break out around popular hub airports.

One airline is trying to solve this problem. The nation’s flag carrier, Qantas, has been hard at work on Project Sunrise. The goal is to run some of the longest non-stop commercial passenger flights ever, with great effort going into solving the technical and economic challenges involved.

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Know Your Food: Organic Production

July 2, 2026 by Jenny List 33 Comments

A few weeks ago we published the first in a new series of articles, Know Your Food. It was born out of the realisation that most people know surprisingly little about what they eat, and to apply a bit of Hackaday curiosity to received opinion on the subject. As we put it then: “To know both how common foodstuffs should be made, as well as how they are made industrially, should be an essential for everyone” We’ll continue in that vein, with a look at organic food.

If you buy your food in a supermarket it’s likely that in the vegetable aisle you’ll be presented with a choice. On one hand you will have the normal vegetable, and on the other and usually for a slightly higher price, the organic version of the same vegetable. What’s going on?

So What Is This Organic Stuff All About?

A watercolour picture of a bucolic scene with a farmhouse surrounded by trees, and some cows in the foreground. — It is unlikely that a typical organic farm in the 2020s will resemble this John Constable painting. John Constable, Public domain.

Organic production is a system of agriculture that emphasises natural fertilisers, pesticides, and farming methods over synthetic or intensive ones. It has its roots in the first half of the 20th century, and as the decades progressed it has become an important sector of agricultural industry. I grew up steeped in organic agriculture because my grandfather was an early adherent in the years following the war, so I’ve seen it from the sharpest end. There is a lot to commend organic production for and plenty of reasons to embrace it, but with that come some problematic aspects, and even dubious claims. Here I’ll try to unpick some of that.

It’s tempting to believe that all organic production is somehow a return to a 19th century rural idyl, complete with the obligatory chickens in the farmyard. Some organic producers do take a slice of this back-to-the-land approach to their craft, but the reality of organic farming is a very modern approach to managing the ecosystem. Organic farmers are not wary of progress, and neither are they reluctant to use pesticides or other chemicals. Instead they do so according to the principles of organic agriculture, so any techniques they use are designed to be beneficial to the ecosystem, and any chemicals have a natural origin. Continue reading “Know Your Food: Organic Production” →

UDP Broadcasting And Easily Finding Network Services

July 1, 2026 by Maya Posch 22 Comments

Local area networks (LANs) that use technologies like Ethernet and Wi-Fi are incredibly useful for letting devices talk with each other. Yet a core problem here is knowing which devices are where on the network, as anyone who has ever tried to add a network printer or network share to their system can probably attest to. Unless you happen to know the IP address of the LAN device, the port, and protocol, the target device may as well be located on the Moon without further help, such as automatic network discovery in lieu of waddling over to the device and reading the label listing its IP address.

Over the decades quite a few ways have been developed to enable such network discovery, with many of them using UDP broadcast as the first step. By broadcasting a global message on the entire LAN, any device that has an actively listening UDP socket on that particular port can parse said message and decide whether it’s feeling sociable enough to reply.

The topic of UDP broadcasting is however not as straightforward as it may sound if you’re just getting started, including the existence of many opinions on the ‘right way’. There is also a massive divide between a sprawling service discovery protocol like mDNS and a light-weight one like that one that I had to implement a few years ago for an open source project.

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How Airspeed Sensors Work

June 30, 2026 by Zoe Skyforest 28 Comments

When you’re driving your car, you’re probably regularly looking at the speedometer to make sure you comply with the local speed limits. The method by which it works is simple enough: the rotation of the wheels is sent mechanically via a cable to a dial on the dash, or an electronic sensor counts the rotations of the drivetrain and an electronically-controlled needle or display shows the speed.

But what about if you were in an aircraft, and the wheels had nothing to do with how fast you were going? How would you even begin to measure speed? There are two ways: there’s a convenient solution to this problem rooted in simple fluid mechanics, and a far-more-complex modern solution. Today, we’ll explore how planes and helicopters are able to figure out how fast they’re going, by the old ways and the new.

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The Teenage Angst Of 3D Printing: Solidoodle, Printrbot, And Bridges

June 29, 2026 by Al Williams 42 Comments

Bridges are a part of our constructed landscape that we take for granted. And bridges by themselves aren’t especially important. What is important is that bridges let you get from one place to another. Technology is often the same. We get from point A to point B through some bridge technology that, probably, most normal people never even notice.

Years ago, point A was commercial 3D printing. Industry had stereolithography, selective laser sintering, fused deposition modeling, and other rapid-prototyping technologies. These were not toys. They were expensive industrial systems used by companies that needed prototypes badly enough to pay serious money for them.

Fast Forward to Today

Today, you can go to a big box store and buy a 3D printer for well under $1,000, and often far less. Modern machines are almost plug-and-play and tend to do all the hard parts for you. That’s point B. How we got between points is a story of hackers who had a dream, and many Hackaday readers lived through it and even played a part in that bridging.

For a long time, RepRap was synonymous with hobby-level 3D printing. The project, started by [Adrian Bowyer] at the University of Bath in 2005, was built around a powerful idea: a machine that could print many of its own parts, thereby helping make more machines. RepRap Darwin reached its early self-replicating milestones in 2008, and the movement produced a thicket of descendants, variants, and arguments about rods, belts, bearings, extruders, firmware, and what “self-replicating” really meant. Of course, the machine could only print some of the parts you needed, but it was still impressive how much of a printer you could make with one printer.

Without RepRap, the desktop 3D printer boom would have looked very different. It created a common pool of ideas: Cartesian frames, printed brackets, hobbed bolts, heated beds, RAMPS boards, Marlin firmware, and a whole common vocabulary. It also created the expectation that a 3D printer was something you could understand, modify, repair, and improve. That expectation would not survive everywhere, but it defined the early culture.

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