Add A Little Quindar To Your Comms For That Apollo-Era Sound

April 30, 2023 by Dan Maloney 9 Comments

If there’s one thing that ties together all the media coming out of the Apollo era, it’s probably the iconic Quindar tones. These quarter-second beeps served as control tones for the globe-spanning communications network needed to talk to the Apollo astronauts, and any attempt to recreate the Apollo-era sound would be glaringly wrong without them. And that’s why [CuriousMarc] whipped up this Quindar tone system.

The video below starts with a detailed treatment of what Quindar tones are and why they were used, a topic we’ve covered ourselves in the past. To recap, Quindar tones are a form of in-band signaling, with a 2,525-Hz pure sine wave intro tone that signaled the transmitters connected to Mission Control in Houston over leased telephone lines to key up. The 2,475-Hz outro tone turned off the transmitters and connected the line to the receivers.

To recreate the sound quality of the original circuitry, and to keep in the retro vibe, [Marc]’s Quindar homage avoided digital circuitry as much as possible, opting instead to generate the two tones with an XR-2206 function generator chip. The chip can rapidly switch back and forth between two frequencies, making it perfect for FSK applications or, in this case, reproducing the two slightly different tones. [Marc] added a dual mono-stable multi-vibrator to pulse the tone, giving the 250-ms pulse, and an audio gate, which uses a MOSFET to switch the tone into an audio stream. All this got soldered up to a piece of perf board and stuffed in the base of a cheap intercom microphone, which while not period accurate still has a cool retro look — and now, a retro sound, too.

Hats off to [CuriousMarc] and his merry band for probing the mysteries of Apollo-era comms and keeping the accomplishments of all those engineers alive. The methods they used are still relevant after all these years, and there seems to be no end to what we can learn from them.

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Rising To The Occasion: A Brief History Of Crewed High Altitude Balloons

April 28, 2023 by Al Williams 11 Comments

Piccard inspects an instrument on his balloon (Image: Bundesarchiv, Bild 102-10382 / CC-BY-SA 3.0)

We think of human flight as a relatively modern affair, with a few claims to the first airplane all around the turn of the last century. But people flew much earlier than that by using hot air balloons as well as gas-filled ones. While the Montgolfier brothers get most of the credit for hot air ballooning in 1783, there are some reports that a Brazilian priest may have lifted himself with a balloon as early as 1709.

Regardless, we’ve had balloons a good century earlier than winged flight, if not longer. While the device is deceptively simple, it is possible to get a balloon to very high altitudes without a lot of specialized technology. Airplanes at high altitudes need a way to get enough oxygen to fuel their engines, or they have to rely on rockets. Either way, there are plenty of design and operational challenges.

Balloons, of course, can simply rise to the occasion. Auguste Piccard and an assistant took a gas-filled balloon to 15,781 meters in 1931. Their gondola was pressurized, and they were the first humans to see the curvature of the Earth and the dark sky above. That record wouldn’t stand for long, though.

CCCP-1

The Soviet Union was keenly interested in Piccard’s flight, and the Soviet Air Force set about to build a research vessel, CCCP-1 (in English, USSR-1), that flew in 1933. The envelope was a large amount of thin fabric impregnated with latex and filled with hydrogen. The air-tight gondola presented several challenges in design. Most of the science experiments were outside, of course, and in 1933, you didn’t have an Arduino and RC servos to control things.

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The Modern WWW, Or: Where Do We Want To Go From Here?

April 27, 2023 by Maya Posch 52 Comments

From the early days of ARPANET until the dawn of the World Wide Web (WWW), the internet was primarily the domain of researchers, teachers and students, with hobbyists running their own BBS servers you could dial into, yet not connected to the internet. Pitched in 1989 by Tim Berners-Lee while working at CERN, the WWW was intended as an information management system that’d provide standardized access to information using HTTP as the transfer protocol and HTML and later CSS to create formatted documents inspired by the SGML standard. Even better, it allowed for WWW forums and personal websites to begin to pop up, enabling the eternal joy of web rings, animated GIFs and forums on any conceivable topic.

During the early 90s, as the newly opened WWW began to gain traction with the public, the Mosaic browser formed the backbone of the WWW browsers (‘web browsers’) of the time, including Internet Explorer – which licensed the Mosaic code – and the Mosaic-based Netscape Navigator. With the WWW standards set by the – Berners-Lee-founded – World Wide Web Consortium (W3C), the stage appeared to be set for an open and fair playing field for all. What we got instead was the brawl referred to as the ‘browser wars‘, which – although changed – continues to this day.

Today it isn’t Microsoft’s Internet Explorer that’s ruling the WWW while setting the course for new web standards, but instead we have Google’s Chrome browser partying like it’s the early 2000s and it’s wearing an IE mask. With former competitors like Opera and Microsoft having switched to the Chromium browser engine that underlies Chrome, what does this tell us about the chances for alternative browsers and the future of the WWW?

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Gen Tojo’s Teeth: Morse Code Shows Up In The Strangest Places

April 21, 2023 by Al Williams 43 Comments

The Baader-Meinhof effect is the common name for what scientists call frequency illusion. Suppose you are watching Star Trek’s Christopher Pike explain how he makes pasta mama, and you’ve never heard of it before. Immediately after that, you’ll hear about pasta mama repeatedly. You’ll see it on menus. Someone at work will talk about having it at Hugo’s. Here’s the thing. Pasta mama was there all along (and, by the way, delicious). You just started noticing it. We sometimes wonder if that’s the deal with Morse code. Once you know it, it seems to show up everywhere.

One of the strangest places we’ve ever heard of Morse code appearing is the infamous case of Tojo’s teeth. If you don’t remember, General Hideki Tojo was one of the main “bad guys” in the Pacific part of World War II. In particular, he is thought to have approved the attack on Pearl Harbor, which started the American involvement in the war globally. Turns out, Tojo would be inextricably tied to Morse code, but he probably didn’t realize it.

The Honorable Attempt

At the end of the war, the US military had a list of people they wanted to try, and Tojo was near the top of their list of 40 top-level officials. As prime minister of Japan, he had ordered the attack that brought the US into the war. He remained prime minister until 1944, when he resigned, but the US had painted him as the face of the Japanese enemy. Often shown in caricature along with Hitler and Mussolini, Tojo was the face of the Japanese war machine to most Americans.

In Allied propaganda, Tojo was one of the “big three”

When Americans tried to arrest him, though, he shot himself. However, his suicide attempt failed. Reportedly, he apologized to the American medics who resuscitated him for failing to kill himself. Held in Sugamo Prison awaiting a trial, he requested a dentist to make him a new set of dentures so he could speak clearly during the trial.

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Retro Gadgets: The 1983 Pocket Oscilloscope

April 14, 2023 by Al Williams 29 Comments

In the 1980s, an oscilloscope was typically a bulky affair with a large CRT, and a heavy power supply. So it probably grabbed a lot of attention in 1983 when Calvert Instruments Incorporated ran an ad in magazines like Radio Electronics. The ad touted a 5 MHz scope that was pocket-sized and weighed 4 ounces. The ad proudly proclaimed: CRT oscilloscopes just became obsolete!

Indeed they would, but if you are wondering who Calvert Instruments was, so are we. We have never heard of them before or since, and we don’t know for certain if any of these devices were ever actually produced. What did it use instead of a CRT? The CI Model 210 Pocket-O-Scope was not only solid state but used an LED screen 1.5 inches square. That’s small, but it packed in 210 LEDs for “high resolution.” We assume that was also the genesis of the model number. Judging from the product picture, there were 14 LEDs in the X direction and 15 in the Y direction. High resolution, for sure!

There were some early LCD scopes (like the Iskrascope and one from Scopex) around the same time, but it would be the 1990s before we would see LCD oscilloscopes and even longer before CRTs were totally squeezed out.

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Retrotechtacular: Voice Controlled Typewriter Science Project In 1958

April 6, 2023 by Al Williams 17 Comments

Hackaday readers might know [Victor Scheinman] as the pioneer who built some of the first practical robot arms. But what was a kid like that doing in high school? Thanks to a film about the 1958 New York City Science Fair, we know he was building a voice-activated typewriter. Don’t believe it? Watch it yourself below, thanks to [David Hoffman].

Ok, we know. Voice typing is no big deal today, and, frankly, [Victor’s] attempt isn’t going to amaze anyone today. But think about it. It was 1958! All those boat anchor ham radios behind him aren’t antiques. That’s what radios looked like in 1958. Plus, the kid is 16 years old. We’d say he did pretty darn good!

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History Of The SPARC CPU Architecture

March 28, 2023 by Joseph Long 31 Comments

[RetroBytes] nicely presents the curious history of the SPARC processor architecture. SPARC, short for Scalable Processor Architecture, defined some of the most commercially successful RISC processors during the 1980s and 1990s. SPARC was initially developed by Sun Microsystems, which most of us associate the SPARC but while most computer architectures are controlled by a single company, SPARC was championed by dozens of players. The history of SPARC is not simply the history of Sun.

A Reduced Instruction Set Computer (RISC) design is based on an Instruction Set Architecture (ISA) that runs a limited number of simpler instructions than a Complex Instruction Set Computer (CISC) based on an ISA that comprises more, and more complex, instructions. With RISC leveraging simpler instructions, it generally requires a longer sequence of those simple instructions to complete the same task as fewer complex instructions in a CISC computer. The trade-off being the simple (more efficient) RISC instructions are usually run faster (at a higher clock rate) and in a highly pipelined fashion. Our overview of the modern ISA battles presents how the days of CISC are essentially over. Continue reading “History Of The SPARC CPU Architecture” →