Retrotechtacular: Air Mail For The Birds

Today, if you want to send a message to a distant location, you’ll probably send an e-mail or a text message. But it hasn’t always been that easy. Military commanders, in particular, have always needed ways to send messages and were early adopters of radio and, prior to that, schemes like semaphores, drums, horns, Aldis lamps, and even barrels of water to communicate over distances.

One of the most reliable ways to pass messages, even during the last world war, was by carrier pigeon.  Since the U.S. Army Signal Corps handled anything that included messages, it makes sense that the War Department issued TM 11-410 about how to use and care for pigeons. Think of it as the network operations guide of 1945. The practice, though, is much older. There is evidence that the Persians used pigeons in the 6th century BC, and Julius Caesar’s army also used the system.

You wouldn’t imagine that drawing an assignment in the Signal Corps might involve learning about breeding pigeons, training them, and providing them with medical attention, but that’s what some Signal Corps personnel did. The Army started experimenting with pigeons in 1878, but the Navy was the main user of the birds until World War I, when the U.S. Pigeon Intelligence Service was formed. In World War II, they saw use in situations where radio silence was important, like the D-Day invasion.

The Navy also disbanded its earlier Pigeon Messenger Service. It then returned to avian communications during the World Wars, using them to allow aviators to send messages back to base without radio traffic. The Navy had its own version of the pigeon manual.

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Lithium-Ion Batteries Power Your Devboards Easily

Last summer, I was hanging out with a friend from Netherlands for a week, and in the middle of that week, we decided to go on a 20 km bike trip to a nearby beach. Problem? We wanted to chat throughout the trip, but the wind noise was loud, and screaming at each other while cycling wouldn’t have been fun. I had some walkie-talkie software in mind, but only a single battery-powered Pi in my possession. So, I went into my workshop room, and half an hour later, walked out with a Pi Zero wrapped in a few cables.

I wish I could tell you that it worked out wonders. The Zero didn’t have enough CPU power, I only had single-core ones spare, and the software I had in mind would start to badly stutter every time we tried to run it in bidirectional mode. But the battery power solution was fantastic. If you need your hack to go mobile, read on.

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Review: The New Essential Guide To Electronics In Shenzhen

The city of Shenzhen in China holds a special fascination for the electronic hardware community, as the city and special economic zone established by the Chinese government at the start of the 1980s it has become probably one of the most important in the world for electronic manufacturing. If you’re in the business of producing electronic hardware you probably want to do that business there, and if you aren’t, you will certainly own things whose parts were made there. From the lowly hobbyist who buys a kit of parts on AliExpress through the project featured on Hackaday with a Shenzhen-made PCB, to the engineer bringing an electronic product to market, it’s a place which has whether we know it or not become part of our lives.

First, A Bit Of History

A picture of booths in a Shenzhen market
These are the markets we have been looking for. Credit: Naomi Wu.

At a superficial level it’s very easy to do business there, as a quick trawl through our favourite Chinese online retailers will show. But when you’ve graduated from buying stuff online and need to get down to the brass tacks of sourcing parts and arranging manufacture, it becomes impossible to do so without  being on the ground. At which point for an American or European without a word of Chinese even sourcing a resistor becomes an impossibly daunting task. To tackle this, back in 2016 the Chinese-American hardware hacker and author Andrew ‘bunnie’ Huang produced a slim wire-bound volume, The Essential Guide to Electronics in Shenzhen. This book contained both a guide to the city’s legendary Huaquanbei electronics marts and a large section of point-to-translate guides for parts, values, and all the other Chinese phrases which a non-Chinese-speaker might need to get their work done in the city. It quickly became an essential tool for sourcing in Shenzhen, and more than one reader no doubt has a well-thumbed copy on their shelves.

There are places in the world where time appears to move very slowly, but this Chinese city is not one of them. A book on Shenzhen written in 2016 is now significantly out of date, and to keep pace with its parts that have since chanced beyond recognition, an update has become necessary. In this endeavour the mantle has passed to the hardware hacker and Shenzhen native Naomi Wu, someone with many years experience in introducing the people, culture, and industries of her city to the world. Her updated volume, The New Essential Guide to Electronics in Shenzhen has been the subject of a recent crowdfunding effort, and I was lucky enough to snag one. It’s a smart hardcover spiral-bound book with a red and gold cover, and it’s time to open it up and take a look. Continue reading “Review: The New Essential Guide To Electronics In Shenzhen”

The Short Workbench

Imagine an electronics lab. If you grew up in the age of tubes, you might envision a room full of heavy large equipment. Even if you grew up in the latter part of the last century, your idea might be a fairly large workbench with giant boxes full of blinking lights. These days, you can do everything in one little box connected to a PC. Somehow, though, it doesn’t quite feel right. Besides, you might be using your computer for something else.

I’m fortunate in that I have a good-sized workspace in a separate building. My main bench has an oscilloscope, several power supplies, a function generator, a bench meter, and at least two counters. But I also have an office in the house, and sometimes I just want to do something there, but I don’t have a lot of space. I finally found a very workable solution that fits on a credenza and takes just around 14 inches of linear space.

How?

How can I pack the whole thing in 14 inches? The trick is to use only two boxes, but they need to be devices that can do a lot. The latest generation of oscilloscopes are quite small. My scope of choice is a Rigol DHO900, although there are other similar-sized scopes out there.

If you’ve only seen these in pictures, it is hard to realize how much smaller they are than the usual scopes. They should put a banana in the pictures for scale. The scope is about 10.5″ wide (265 mm and change). It is also razor thin: 3″ or 77 mm. For comparison, that’s about an inch and a half narrower and nearly half the width of a DS1052E, which has a smaller screen and only two channels.

A lot of test gear in a short run.

If you get the scope tricked out, you’ve just crammed a bunch of features into that small space. Of course, you have a scope and a spectrum analyzer. You can use the thing as a voltmeter, but it isn’t the primary meter on the bench. If you spend a few extra dollars, you can also get a function generator and logic analyzer built-in. Tip: the scope doesn’t come with the logic analyzer probes, and they are pricey. However, you can find clones of them in the usual places that are very inexpensive and work fine.

There are plenty of reviews of this and similar scopes around, so I won’t talk anymore about it. The biggest problem is where to park all the probes. Continue reading “The Short Workbench”

On An Aging Space Station, Air Leaks Become Routine

Anyone who’s ever owned an older car will know the feeling: the nagging worry at the back of your mind that today might be the day that something important actually stops working. Oh, it’s not the little problems that bother you: the rips in the seats, the buzz out of the rear speakers, and that slow oil leak that might have annoyed you at first, but eventually just blend into the background. So long as the car starts and can get you from point A to B, you can accept the sub-optimal performance that inevitably comes with age. Someday the day will come when you can no longer ignore the mounting issues and you’ll have to get a new vehicle, but today isn’t that day.

Looking at developments over the last few years one could argue that the International Space Station, while quite a bit more advanced and costly than the old beater parked in your driveway, is entering a similar phase of its lifecycle. The first modules of the sprawling orbital complex were launched all the way back in 1998, and had a design lifetime of just 15 years. But with no major failures and the Station’s overall condition remaining stable, both NASA and Russia’s Roscosmos space agency have agreed to several mission extensions. The current agreement will see crews living and working aboard the Station until 2030, but as recently as January, NASA and Roscosmos officials were quoted as saying a further extension isn’t out of the question.

Still, there’s no debating that the ISS isn’t in the same shape it was when construction was formally completed in 2011. A perfect case in point: the fact that the rate of air leaking out of the Russian side of the complex has recently doubled is being treated as little more than a minor annoyance, as mission planners know what the problem is and how to minimize the impact is has on Station operations.

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Hackaday Links: March 10, 2024

We all know that we’re living in a surveillance state that would make Orwell himself shake his head, but it looks like at least one company in this space has gone a little rogue. According to reports, AI surveillance start-up Flock <<insert gratuitous “What the Flock?” joke here>> has installed at least 200 of its car-tracking cameras on public roads in South Carolina alone. That’s a serious whoopsie, especially since it’s illegal to install anything on state infrastructure without permission, which it appears Flock failed to obtain. South Carolina authorities are making a good show of being outraged about this, but it sort of rings hollow to us, especially since Flock now claims that 70% of the population (of the USA, we presume) is covered by their technology. Also, police departments across the country are in love with Flock’s service, which lets them accurately track the movements of potential suspects, which of course is everyone. No word on whether Flock will have to remove the rogue cameras, but we’re not holding our breath.

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Retro Gadgets: Pay TV In The 1960s

These days, paying for TV programming is a fact of life. You pay your cable company or some streaming service and the only question is do you want Apple TV and Hulu or would you rather switch one out for NetFlix? But back in the 1960s, paying for TV seemed unthinkable and was quite controversial. Cable TV systems were rare, and the airwaves were a public resource, so allowing someone to charge to watch TV on the public airwaves was hard to imagine. That was the backdrop behind the Telemeter — an early attempt to monetize TV programming that was more like a pay phone than a modern streaming service.

Rear view of the telemeter and coin box

[Lothar Stern] wrote about the device in the November 1959 issue of Popular Mechanics (see page 220). The device looked like a radio that sat on top of your TV. It added a whopping three pay-TV channels, and inside was a coin box, and — no kidding — a tape punch or recorder. These three channels were carried from a Telemeter studio over what appears to be a dedicated cable strung on existing phone poles.

Of course, TVs with coin boxes were nothing new. But those TVs were found in public places, airports, and hotels. The money was simply to turn the TV on for a set amount of time. This was different. A set-top box unscrambled channels delivered over a dedicated cable. Seems like old hat today, but a revolutionary idea in 1959.

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