TV Repair By Mail

November 17, 2022 by 49 Comments

I don’t think there was ever a correspondence school called the “Close Cover Before Striking School” but since book matches — which used to be a thing when most people smoked — always had that text on them anyway perhaps there should have been. There was a time when electronic magazines, billboards, and even book matches were constantly bombarding us with ads to have a career in electronics. Or computers. Or TV repair. So while we think of distance learning as a new idea, really it is just the evolution of these old correspondence schools which date back quite some time.

How far exactly? Hard to say. There’s evidence of some distance learning going back as far as 1728. In 1837, there was a correspondence course to learn shorthand. By 1858, the University of London started its external program for correspondence work and the University of Chicago had a home study division in 1892.  Radio was an early choice of topic, too. In the United States, the United Wireless Telegraph company started a training school — later the Marconi Institute — in 1909. However, it is doubtful that there was any correspondence training going on there until much later.

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Tiny Palm-Sized Crossbow Build Is Cute And Dangerous

November 17, 2022 by 17 Comments

Crossbows were a major development in the history of weaponry. They enabled lesser-skilled soldiers to shoot arrows at great speed in a compact form-factor. You can now build your own tiny version, thanks to this creation from [Maciej Nowak].

The main body of the crossbow was cut from a piece of aluminium bar stock, being shaped with an angle grinder. A slot was then machined to mount the crossbar and pulleys. A round piece of aluminium tube serves as a spring holder, and the spring is tensioned via pulling back a length of sailing rope to rest on a latch. The latch is released by a small trigger, just like on a full-size crossbow.

The arrows (or bolts, more typically) were made by machining skewers and giving them hard metal tips cut from nails. This enables them to penetrate apples, and presumably other fruits. They fly straight enough to reliably hit a target from a meter or two away.

We’ve seen other crossbow builds before, like this one that fires cannonballs! Just be careful where you aim, and don’t get yourself or anyone else hurt.

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Number Stations Gone Wild

November 17, 2022 by 18 Comments

[Ringway Manchester] has an interest in numbers stations. These mysterious stations send presumably coded numbers or other coded information. However, it is rare that anyone claims credit for these stations. Normally they operate with military-like precision, adhering to strict operating schedules and sending out their messages error-free. [Ringway] looks at five times when things didn’t go as planned for these spy stations.

Perhaps it isn’t surprising, however, as machines have likely replaced human operators. That makes them prone to errors when the computers go awry. Many of the errors are ones of frequency, where two number stations wind up transmitting at once. We suppose spies all use the same few frequencies. Some, however, also had computers go haywire and start going through the alphabet which, of course, could have been part of some secret message protocol, but appeared more likely to be a simple mistake.

We were amused, though, to hear the story of a Czech spy station that not only had a licensed call sign but would send QSL cards to people who reported reception. Perhaps they didn’t get the memo about secrecy!

We’ve listened to a few number stations in our time. If you don’t have a suitable antenna, you can always try hunting them online. But don’t expect to catch them making any mistakes.

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Crazy Bike Frame Made Out Of 147 Nuts

November 16, 2022 by 39 Comments

Bike frames are most commonly made out of steel. If you’ve got money for something nicer though, you might go with something in aluminium or carbon fiber. [The Q] went completely off-the-wall with this build, though, constructing a bicycle frame out of 147 nuts. 

Those forks don’t inspire confidence.

Yes, a variety of nuts in various sizes were laid out and welded together to make the frame. The overall layout is a conventional diamond frame, albeit constructed out of many nuts stuck together rather than with tubes. Notably though, several important areas aren’t made in this way. The front and rear dropouts are made of sheet steel, and the bottom bracket, seat post mount, and headstem are all made of steel tube. After welding, the bike was given an attractive coat of grey paint. It was then laced up with the usual running gear and given a set of chunky mountain bike tires.

We wouldn’t want to push this frame too hard over bumps and jumps. The video only shows the nuts being joined with tack welds, and the front forks look particularly fragile. One suspects a decent shock loading could snap parts of the frame apart. Overall, though, it’s an eye-catching bike that has plenty of easy places to attach a lock. For an ultra-fashionable city-bound cruiser, it would be hard to beat.

We’ve featured some weird and wonderful bikes over the years, including this tasteful plywood design. Video after the break.

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Is This The Smallest CP/M Machine Ever?

November 16, 2022 by 22 Comments

If you had an office word processor in the late 1970s, the chances are it ran Digital Research’s CP/M operating system. IBM went for Microsoft in the 1980s and the once-dominant player fell on hard times, but it survives today as a popular choice on retrocomputer platforms. Even the more compact Z80 systems are a little large for 2022, so when [Kian Ryan] needed the ultimate in CP/M portability it fell on a more modern piece of silicon. Hence he’s put it on a tiny RP2040-based board from Pimoroni alongside an Adafruit micro SD card breakout.

The tiny hardware is neat of course, but the real star of the show is the software. Non-CP/M aficionados will be interested to learn about RunCPM, and for this project, RunCPM 2040. This provides an emulated environment on a host microcontroller to run CP/M, allowing the operating system to be hosted on easier hardware than some of the original machines.

All this makes for a tiny development machine, but perhaps of more interest would be a machine that’s all-in-one with a display and perhaps a keyboard. The RP2040 is interesting in this case because of those programmable state machines. Could it be made to run a video display alongside RunCPM? We hope someone has a go at writing it.

Will The Fax Machine Ever Stop Singing?

November 16, 2022 by 43 Comments

Throughout the 80s and 90s, you couldn’t swing a stapler around any size office without hitting a fax machine. But what is it about the fax machine that makes it the subject of so much derision? Is it the beep-boops? The junk faxes? Or do they just seem horribly outdated in the world of cloud storage and thumb drives? Perhaps all of the above is true. While I may be Hackaday’s resident old school office worker et cetera, it may surprise you to learn that I don’t have a fax machine. In fact, the last time I had to fax something, I recall having to give my email address to some website in order to send a single fax for free.

Over across the pond, the UK government has decided to nix the requirement for fax services under something called the Universal Service Order (USO) legislation, which essentially ensures that residents all across the UK have access to phone services at a price they can afford. The UK’s Office of Communications, aka Ofcom, have announced recently that they are in agreement with the government. Since the industry is moving away from the public switched telephone network (PSTN) to IP telephony, the fax machine won’t work the same way.

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Reverse Engineering Reveals EV Charger Has A Sense Of Security

November 16, 2022 by 11 Comments

As more and more electric vehicles penetrate the market, there’s going to have to be a proportional rise in the number of charging stations that are built into parking garages, apartment complexes, and even private homes. And the more that happens, the more chargers we’re going to start seeing where security is at best an afterthought in their design.

But as this EV charger teardown and reverse engineering shows, it doesn’t necessarily have to be that way. The charger is a Zaptec Pro station that can do up to 22 kW, and the analysis was done by [Harrison Sand] and [Andreas Claesson]. These are just the kinds of chargers that will likely be widely installed over the next decade, and there’s surprisingly little to them. [Harrison] and [Andreas] found a pair of PCBs, one for the power electronics and one for the control circuits. The latter supports a number of connectivity options, like 4G, WiFi, and Bluetooth, plus some RFID and powerline communications. There are two microcontrollers, a PIC and an ARM Cortex-A7.

Despite the ARM chip, the board seemed to lack an obvious JTAG port, and while some unpopulated pads did end up having a UART line, there was no shell access possible. An on-board micro SD card slot seemed an obvious target for attack, and some of the Linux images they tried yielded at least a partial boot-up, but without knowing the specific hardware configuration on the board, that’s just shooting in the dark. That’s when the NAND flash chip was popped off the board to dump the firmware, which allowed them to extract the devicetree and build a custom bootloader to finally own root.

The article has a lot of fascinating details on the exploit and what they discovered after getting in, like the fact that even if you had the factory-set Bluetooth PIN, you wouldn’t be able to get free charging. So overall, a pretty good security setup, even if they were able to get in by dumping the firmware. This all reminds us a little of the smart meter reverse engineering our friend [Hash] has been doing, in terms of both methodology and results.

Thanks to [Thinkerer] for the tip.