Author: Al Williams

4389 Articles

History Of Forgotten Moon Bases

June 16, 2025 by 39 Comments

If you were alive when 2001: A Space Odyssey was in theaters, you might have thought it didn’t really go far enough. After all, in 1958, the US launched its first satellite. The first US astronaut went up in 1961. Eight years later, Armstrong put a boot on the moon’s surface. That was a lot of progress for 11 years. The movie came out in 1968, so what would happen in 33 years? Turns out, not as much as you would have guessed back then. [The History Guy] takes us through a trip of what could have been if progress had marched on after those first few moon landings. You can watch the video below.

The story picks up way before NASA. Each of the US military branches felt like it should take the lead on space technology. Sputnik changed everything and spawned both ARPA and NASA. The Air Force, though, had an entire space program in development, and many of the astronauts for that program became NASA astronauts.

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Retrotechtacular: Arthur C. Clarke Predicts The Future

June 16, 2025 by 24 Comments

Predicting the future is a dangerous occupation. Few people can claim as much success as Arthur C. Clarke, the famous science and science fiction author. Thanks to the BBC and the Australian Broadcasting Company, we can see what Sir Arthur thought about the future in 1964 and then ten years later in 1974.

Perhaps his best-known prediction was that of communication satellites, but he called quite a few other things, too. Like all prognosticators, he didn’t bat a thousand, and he missed a wrinkle or two, but overall, he has a very impressive track record.

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Dummy Plug Gets Smarter With Raspberry Pi

June 16, 2025 by 21 Comments

[Doug Brown] had a problem. He uses a dummy HDMI plug to fool a computer into thinking it has a monitor for when you want to run the computer headless. The dummy plug is a cheap device that fools the computer into thinking it has a monitor and, as such, has to send the Extended Display ID (EDID) to the computer. However, that means the plug pretends to be some kind of monitor. But what if you want it to pretend to be a different monitor?

The EDID is sent via I2C and, as you might expect, you can use the bus to reprogram the EEPROM on the dummy plug. [Doug] points out that you can easily get into trouble if you do this with, for example, a real monitor or if you pick the wrong I2C bus. So be careful.

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Laptop Brick Is Brought Back From The Brink

June 14, 2025 by 9 Comments

We’ve all been there. [Kasyan TV] had a universal adapter for a used laptop, and though it worked for a long time, it finally failed. Can it be fixed? Of course, it can, but it is up to you if it is worth it or not. You can find [Kasyan’s] teardown and repair in the video below.

Inside the unit, there were a surprising number of components crammed into a small area. The brick also had power factor correction. The first step, of course, was to map out the actual circuit topology.

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Cassette Data Storage From The 1970s

June 13, 2025 by 69 Comments

When home computers first appeared, disk drives were an expensive rarity. Consumers weren’t likely to be interested in punch cards or paper tape, but most people did have consumer-grade audio cassette recorders. There were a few attempts at storing data on tapes, which, in theory, is simple enough. But, practically, cheap audio recorders are far from perfect, which can complicate the situation.

A conference in Kansas City settled on a standard design, and the “Kansas City standard” tape format appeared. In a recent video, [Igor Brichkov] attempts to work with the format using 555s and op amps — the same way computers back in the day might have done it. Check out the video below to learn more.

These days, it would be dead simple to digitize audio and process it to recover data. The 1970s were a different time. The KC standard used frequency shift method with 2.4 kHz tones standing in for ones, and 1.2 kHz tones were zeros. The bit length was equal (at 300 baud), so a one had 8 cycles and a zero had 4 cycles. There were other mundane details like a start bit, a minimum stop bit, and the fact that the least significant bit was first.

The real world makes these things iffy. Stretched tape, varying motor speeds, and tape dropouts can all change things. The format makes it possible to detect the tones and then feed the output to a UART that you might use for a serial port.

There were many schemes. The one in the video uses an op-amp to square up the signal to a digital output. The digital pulses feed to a pair of 555s made to re-trigger during fast input trains but not during slower input trains. If that doesn’t make sense, watch the video!

The KC standard shows up all over the place. We’ve even used it to hide secret messages in our podcast.

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Simple Open Source Photobioreactor

June 12, 2025 by 11 Comments

[Bhuvanmakes] says that he has the simplest open source photobioreactor. Is it? Since it is the only photobioreactor we are aware of, we’ll assume that it is. According to the post, other designs are either difficult to recreate since they require PC boards, sensors, and significant coding.

This project uses no microcontroller, so it has no coding. It also has no sensors. The device is essentially an acrylic tube with an air pump and some LEDs.

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Crowdsourcing SIGINT: Ham Radio At War

June 12, 2025 by 18 Comments

I often ask people: What’s the most important thing you need to have a successful fishing trip? I get a lot of different answers about bait, equipment, and boats. Some people tell me beer. But the best answer, in my opinion, is fish. Without fish, you are sure to come home empty-handed.

On a recent visit to Bletchley Park, I thought about this and how it relates to World War II codebreaking. All the computers and smart people in the world won’t help you decode messages if you don’t already have the messages. So while Alan Turing and the codebreakers at Bletchley are well-known, at least in our circles, fewer people know about Arkley View.

The problem was apparent to the British. The Axis powers were sending lots of radio traffic. It would take a literal army of radio operators to record it all. Colonel Adrian Simpson sent a report to the director of MI5 in 1938 explaining that the three listening stations were not enough. The proposal was to build a network of volunteers to handle radio traffic interception.

That was the start of the Radio Security Service (RSS), which started operating out of some unused cells at a prison in London. The volunteers? Experienced ham radio operators who used their own equipment, at first, with the particular goal of intercepting transmissions from enemy agents on home soil.

At the start of the war, ham operators had their transmitters impounded. However, they still had their receivers and, of course, could all read Morse code. Further, they were probably accustomed to pulling out Morse code messages under challenging radio conditions.

Over time, this volunteer army of hams would swell to about 1,500 members. The RSS also supplied some radio gear to help in the task. MI5 checked each potential member, and the local police would visit to ensure the applicant was trustworthy. Keep in mind that radio intercepts were also done by servicemen and women (especially women) although many of them were engaged in reporting on voice communication or military communications.

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