How TTY Opened Up The Phones For The Hard Of Hearing

April 30, 2026 by Zoe Skyforest 11 Comments

The telephone was an invention that revolutionized human communication. No more did you have to physically courier a letter from one place to another, or send a telegram, or have a runner carry the message for you. Instead, you could have a direct conversation with another person a great distance away. All well and good if you can speak and hear, of course, but rather useless if you happen to be deaf.

Those hard of hearing were not left entirely out of the communication revolution, however. Well before IP switched networks and the Internet became a thing, there was already a way for the deaf to communicate over the plain old telephone network—thanks to the teletypewriter!

Over The Wires

The teletypewriter (TTY) has been around for a long time. The first device came into being in 1964, developed by James C. Marsters and Robert Weitbrecht, both deaf. Their idea was to create a method for deaf individuals to communicate over the phone network in a textual manner. To this end, the group sourced teleprinters formerly used by the US Department of Defense, and hooked them up with acoustic couplers that would allow them to mate with the then-ubiquitous AT&T Model 500 telephone. Thus, the TTY was born. A user could dial another TTY machine, and key in a message, which would print out at the other end. The receiving user could then respond in turn in the same manner.

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What Have We Dumped On The Moon?

April 22, 2026 by Al Williams 53 Comments

If you read a headline that signs of intelligent life were found on the moon, you might suspect a hoax. But they are there! Humans have dumped a lot of stuff on the moon, both in person and via uncrewed rockets. So after the apocalypse, what strange things will some alien exo-archaeologist find on our only natural satellite?

The Obvious

Of course, we’ve left parts of rockets, probes, and rovers. Only the top part of the Apollo Lunar Excursion Module left the moon. (See for yourself in the Apollo 17 ascent video below.) The bottoms are still there, along with the lunar rovers and a bunch of other science instruments and tools. There are boots and cameras, as you might expect.

But what about the strange things? As of 2012, NASA compiled a list of all known lunar junk that originated on Earth. The list starts with material from the non-Apollo US programs like the Surveyor and Lunar Prospector missions. Next up is the Apollo stuff, which is actually quite a bit: an estimated 400,000 pounds, we’ve heard. This ranges from the entire descent stage and lunar overshoes to urine bags. There are even commemorative patches and a gold olive branch.

After that, the list shows what’s known to be on the surface from the Russian space program, along with objects of Chinese, Indian, Japanese, and European origin.

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SuperDisk: The Better Floppy That Never Caught On

April 21, 2026 by Zoe Skyforest 49 Comments

Once the microcomputer era got going in earnest, the floppy disk quickly supplanted the tape as the portable storage method of choice. They were never particularly large, but they were fine for the average user to get by.

At the same time, it wasn’t long before heavier-duty removable storage solutions hit the market for power users who needed to move many megabytes at a time. In the 1980s, these were primarily the preserve of big print shops, corporate users, and governments. By the 1990s, even the mildly savvy computerist was starting to chafe against the tyrannical 1.44 MB limit of the regular 3.5″ diskette. Against this backdrop launched the SuperDisk—the product which hoped to take the floppy format to the next level, yet faltered all the same.

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Making A Bronze Mirror From Scratch

April 17, 2026 by Maya Posch 18 Comments

Although modern-day silvered glass mirrors have pretty much destroyed the market for bronze mirrors, these highly polished pieces of metal once were the pinnacle of mirror technology. Due to the laborious process required these mirrors saw use essentially only by the affluent. That said, how hard would it be to make a bronze mirror today with all of the modern technologies that even a hobbyist can acquire for their shed? Cue [Lundgren Bronze Studios] giving it a shot, starting by casting something flat-ish to start polishing.

Just getting that initial shape to start polishing is a chore, with hammering out the shape possibly being also a viable method. When casting metal it’s tricky to avoid having air bubbles and other defects forming, though using a sand mold seems to help a lot.

After you have the rough shape, polishing using power tools seems like cheating, but as you can see in the video even going from 50 to 8000 grit with a rotating disc left countless scratches. Amusingly, hand sanding did a much better job of removing the worst scratches, following which a polishing compound helped to bring out that literal mirror finish.

A quick glance at the Wikipedia entry for bronze mirrors shows that a tin-bronze alloy like speculum metal was used for thousands of years as it was much easier to polish to a good mirror finish. The metallurgy of what may seem like just a vanity item clearly goes deeper than just polishing up a metal surface.

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Four Choppers And A Blimp: The Bizarre Piasecki Helistat

April 14, 2026 by Tyler August 24 Comments

Over two decades after it was last deflated, detached from its gondola, and crated up at Lakehurst, the gas bag of an N-class ZPG-2W blimp was broken out and dusted off for what might have been the most bizarre afterlife in aviation history: as a key building block for the U.S. Forest Service’s Piasecki PA-97 Helistat.

Just look at it! It’s an antique blimp gas bag, four war-surplus helicopters pulled from the boneyard, and a whole maze of aluminum tubing. That the U.S. Forest Service, of all agencies, was the one building what amounts to the airship version of an X-plane is also weird enough to be called bizarre. Getting Frank Piasecki to design this thing, a man who did as much as almost anyone else to kill the airship, might be considered ironic, but to stay on theme, I’ll call it bizarre.

If you’re not already a quadrotor-blimp afficionado, we have some explaining to do.

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Skylab Under The Ocean

April 13, 2026 by Al Williams 21 Comments

A crew lives on a station in a hostile environment. Leaving that environment requires oxygen tanks and specialized gear to deal with pressure differentials. A space station? Nah. A base built on the ocean floor. The US Navy was interested in such a base in the 1960s, and bases like this are a staple of science fiction. But today, we see more space stations than underwater bases. Have you ever wondered why?

Diving deep underwater is a tricky business. At a certain depth, the pressure forces gas like nitrogen to dissolve into your body. By itself, this isn’t a problem, but when you ascend, it is a big problem. If the gas all comes out at the same time, you get bubbles, which can cause decompression sickness, commonly called the bends. The exact problems vary, but the bends often cause extreme joint pain, fatigue, or a rash. Sometimes people die.

While you think of the bends as a deep-sea diver’s problem, it can also happen in airplanes and outer space. Any time you go from high pressure to low pressure quickly, you are subject to decompression sickness. Depending on what you are doing, there are different ways to mitigate the problem. For diving, traditionally, you simply don’t surface too quickly.

You dive, do your work, and then head towards the surface, stopping at preset stops to let the pressure equalize gradually. Physics is a bear, though. The longer you stay at a given depth, the longer you have to decompress.

That means you rapidly reach a point of diminishing returns. Suppose you dive to the ocean floor. You spend an hour working. Then you have to spend, say, eight hours gradually rising to the surface. That makes extended operations at significant depth impractical.

George Bond was thinking about all this and had an interesting idea. It is true that, in general, the longer you stay down, the more gas your body absorbs. But it is also true that, eventually, your tissues saturate, and then you don’t absorb any more.

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The Brits Made A Rocket. What Happened To It?

April 9, 2026 by Jenny List 22 Comments

Like many long-established broadcasters, the BBC put out a selection of their archive material for us all to enjoy online. Their most recent may be of interest to Hackaday readers and has more than a bit of personal interest to your scribe, as it visits the Spadeadam rocket test range on the event of its closure in 1973. This marked the final chapter in the story of Blue Streak, the British intercontinental missile project that later became part of the first European space launcher.

It’s possible citizens of every country see their government as uniquely talented in the throwing away of taxpayer’s money, but the sad story here isn’t in Blue Streak itself which was obsolete as a missile by the time it was finished. Instead it lies in the closure of the test range as part of the ill-advised destruction of a nascent and successful space industry, just as it had made the UK the third nation to have successfully placed a satellite in orbit.

We normally write in the second person in our daily posts here at Hackaday, but for now there’s a rare switch into the first person. My dad spent a large part of the 1950s working as a technician for de Haviland Propellers, later part of Hawker Siddeley, and then British Aerospace. He was part of the team working on Blue Streak at Spadeadam and the other test site at RAF Westcott in Buckinghamshire, and we were brought up on hair-raising tales of near-disasters in the race to get British nukes flying. He’s not one of the guys in the video below, as by that time he was running his metalwork business in Oxfordshire, but I certainly recognise the feeling of lost potential they express. Chances are I’ll never visit what remains of the Spadeadam test stands in person as the site is now the UK’s electronic warfare test range, so the BBC film represents a rare chance for a closer look.

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