A Ham Radio Answering Machine

For those who grew up with a cell phone in their hand, it might be difficult to imagine a time where the phone wasn’t fully integrated with voicemail. It sounds like a fantastical past, yet at one point a separate machine needed to be attached to the phone to record messages if no one was home to answer. Not only that, but a third device, a cassette tape, was generally needed as a storage device to hold the messages. In many ways we live in a much simpler world now, but in the amateur radio world one group is looking to bring this esoteric technology to the airwaves and [saveitforparts] is demonstrating one as part of a beta test.

The device is called the Boondock Echo, and while at its core it’s an ESP32 there’s a lot going on behind the scenes. It has an audio interface which is capable of connecting to a radio given the correct patch cable; in this case with a simple Baofeng handheld unit. The answering machine can record any sounds that come in. However, with a network connection the recordings are analyzed with an AI which can transcribe what it hears and even listen for specific call signs, then take actions such as sending emails when it hears triggers like that. Boondock also plans for this device to be capable of responding as well, but [saveitforparts] was not able to get this working during this beta test.

While an answering machine might seem like a step backwards technologically, an answering machine like this, especially when paired with Google Voice-like capabilities from an AI, has a lot of promise for ham radio operators. Even during this test, [saveitforparts] lost a radio and a kind stranger keyed it up when it was found, which was recorded by the Boondock Echo and used to eventually recover the radio. Certainly there are plenty of other applications as well, such as using AI instead of something like an Arduino to do Morse decoding.

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Cold War Spying And The Questionable Use Of Smuggled Blueprints In Developing Supersonic Airliners

Three views of a Boeing 2707-300.
Three views of a Boeing 2707-300.

Although spying is a time-honored tradition, the sheer scope of it reached a fever pitch during the Cold War, when everyone was spying on everyone, and conceivably for both sides at the same time. In an era where both McCarthyism and the character of James Bond enjoyed strong popularity, it should come as no surprise that a project of geopolitical importance like the development of the world’s first supersonic airliner would come amidst espionage, as well as accusations thereof. This is the topic of a documentary that recently aired on Channel 4 in the UK called Concorde: The Race for Supersonic, yet what is the evidence that the Soviet Tu-144 truly was just a Concorde clone, a derogatory nicknamed ‘Concordski’?

At the time that the Concorde was being developed, there wasn’t just the competition from the Tu-144 team, but also the Boeing 2702 (pictured) and Lockheed L-2000, with the latter two ultimately being cancelled. Throughout development, all teams converged on a similar design, with a delta wing and similar overall shape. Differences included the drooping nose (absent on Boeing 2707-300) and use of canards (present on Tu-144 and 2707-200), and wildly different engines, with the production Tu-144S requiring an afterburner on its Kuznetsov NK-144A engines just like the Concorde, before the revised Tu-144D removing the need for afterburners with the Koliesov RD36-51 engines.

Although generally classified as a ‘failure’, the Tu-144’s biggest issues appear to have been due to the pressure on the development team from Soviet leadership. Once the biggest issues were being fixed (Tu-144D) it saw continued use for cargo use and even flying missions for NASA (Tu-144LL) until 1999. Although Soviet spies were definitely caught with Concorde blueprints, the practical use of these for the already overburdened Tu-144 development team in terms of reverse-engineering and applying it to the Tu-144’s design would be limited at best, which would seem to be reflected in the final results.

Meanwhile, although supersonic airliners haven’t been flying since the Concorde retired in 2003, the Lockheed Martin X-59 Quesst supersonic airplane that is being built for NASA looks set to fix the sonic boom and fuel usage issues that hampered supersonic flight. After the L-2000 lost to Boeing so many decades ago, it might be Lockheed that has the last laugh in the race towards supersonic flight for airliners.

(Top image: Tu-144 with distinctive droop nose at the MAKS-2007 exhibition)

MOSFETs — The Hidden Gate

How many terminals does a MOSFET have? Trick question since most have three leads, even though there are really four connections to the underlying device. It isn’t a conspiracy, though and [Aaron Lanterman] talks about how MOSFETs really work and why thinking of them as three-terminal devices can lead you astray in a recent video that you can watch below.

Like many people, [Aaron] points out the parallel between a triode vacuum tube and a MOSFET. That’s not surprising, since a solid-state tube was exactly what they were looking for when they developed the FET. Since tubes and FETs are both voltage controllers, it is easy to think of the gate as the grid, the source as the cathode, and the drain as the plate. But, [Aaron] shows this isn’t really a very accurate picture.

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Metronome Flashes And Vibrates To The Beat

Annoying though they can be, if you play any kind of instrument, you will definitely benefit from using a metronome. While many of them thock or otherwise tock, the VRRVRR metronome from [Turi] works a little differently.

In addition to flashing LEDs, the VRRVRR contains a small vibrating motor. If you’re wondering about the name, it comes from the fact that it vibrates and makes a sort of vrr vrr sound. Need to be quiet? A small switch on the side shuts off the vibrations.

The 4×4 keypad really allowed [Turi] to cram in a bunch of features using both short and long press to do different things. On short press, the digits set the tempo. When not typing in a tempo, zero can be used to enter a tempo by tapping. The letters load preset tempos, and the +/- keys increase and decrease it.

Inside the basswood enclosure is a Raspberry Pi Pico, the vibration motor, and various other bits and bobs that make it go. There’s even an LED to indicate that it’s time to charge the lithium battery. If you want to build your own, head on over to GitHub, but be sure to take the brief VRRVRR tour after the break.

We don’t see too many metronomes around here, but we do have this nice teardown to offer you.

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Switching Converter For EEPROM Programmer Taxes Solderless Breadboard

We all know that solderless breadboards have their limitations. All that stray capacitance can play hell with circuits, especially high-speed stuff, but they’re so darn useful that avoiding them in favor of some other prototyping method can be really hard. So we often just forge ahead, plugging in our parts and hoping for the best

A recent veteran of the breadboard battle is [Anders Nielsen], who kicked off a new project by prototyping this high-voltage boost converter on a breadboard, with mixed results. The project is a scratch-built programmer for old-school ROM chips, a task normally farmed out to a dedicated programmer, but where’s the sport in that? Besides, this is the future, and generating the 12 to 14 volts needed should be a snap. And it would be, except for the fact that his chosen chip, a MIC2288 switching boost regulator, is only available in an SMD package. Getting the chip and a few other SMD support components onto breadboard-compatible breakouts proved to be challenging, and getting it working once it was there was even more work.

A lot of the trouble was down to simple breadboarding errors, but the big problem was the input capacitance, which [Anders] had to fiddle with quite a bit to get the converter to 14 volts. The current maxes out at about 25 mA before the voltage starts dropping, which just might be enough to burn those old chips, so we’ll call this a provisional win and see what happens when he builds the rest of the programmer.

[Anders]’ experience here raises a good question: what’s the best way to prototype using fussy SMD components? PCBs are cheap enough that it’s tempting to go straight to one, but swapping parts in and out like he had to do here to get everything just right would be much harder that way. We’re not sure we know the answer, but we’re pretty sure we’ll hear your thoughts on that in the comments section.

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Check Your Board: Call For Submissions

As both beginning hackers and Silicon Valley investors alike keep discovering, there are a lot of differences between hardware and software. One important difference is cost of iterating over a design. In software, you can comfortably rerun your build process and push updates out near instantly to tons of users. In hardware, all of that costs money, and I do mean, it costs way more money than you’d want to spend.

When I see people order boards that could never work because of some fundamental design assertions, with mistakes entirely preventable, it hurts. Not in an “embarrassment” way – it’s knowing that, if they asked someone to take a look at the design, they could’ve received crucial feedback, pulled the traces on the board differently or added some components, and avoided spending a significant chunk of money and time expecting and assembling a board that has a fundamental mishap.

Every thing like this might set a beginner back on their hacker journeys, or just have them spend some of their valuable time, and we can do a ton to prevent that by simply having someone experienced take a look.

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Hackaday Podcast Ep 247: Cameras From Gingerbread Or Hardboard, And The Insecurity Of Bluetooth

This week, Editor-in-Chief Elliot Williams and Kristina Panos met up to discuss the best hacks of the previous week. We have no nerdy news this week, but is that necessarily a bad thing?

Speaking of nothingness, we have no winner for What’s That Sound because all six people who responded were wrong. Was the sound of Clippy too obscure?

But then it’s on to the hacks, beginning with an awesome autonomous excavator that, among other things, lays boulders algorithmically to build load-bearing walls without any mortar or cement. From there, it’s old school meets new school in the form of a laser-cut fox-wedged mortise and tenon joint. We take a look at a couple of simple cameras, making dry ice from seashells, and a really tiny POV display where everything spins. Finally, we talk about how small that proposed Italian lunar outpost is, and discuss whether rating airlines would help stop the spread of diseases.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download and savor at your leisure.

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