Commodore Datassette Does Barbershop Quartet

October 20, 2023 by Kristina Panos 3 Comments

Okay, now this is just plain fun. [Linus Åkesson] modified a Commodore Datassette player to move its “mouth” and, when quadrupled, sing a clever barbershop tune called “Sweet End of Line” that’s a play on “Sweet Adeline“, a top hit from the summer of 1903.

What? Let us explain. Those with Commodore 64s who lacked disk drives often had the Datassette — a magnetic storage tape device, or cassette player used to load and save files. But they couldn’t open the doors themselves with a keypress, and they certainly couldn’t sing barbershop.

First off, [Linus] redirected the current that drives the magnetizing tape head through a speaker coil instead. Then he replaced the motor with a servo that opens the lid from the inside. A simple rubber band pulls the lid back shut. Software-wise, [Linus] is using a timer interrupt to run code that toggles the output signal, the rate of which determines the pitch.

Don’t worry — all of these modifications are reversible, so no Datassettes were truly harmed in the making. Don’t forget to check out the brief build/demo video after the break.

We’ve seen our share of tape players, but we’d never seen one with a crank until recently.

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2023 Halloween Hackfest: Candy Basket Sees You Coming

October 14, 2023 by Kristina Panos 5 Comments

On Halloween, some people can’t or don’t want to open the door for various reasons. Maybe they have a cat that likes to escape every chance it gets, or maybe their favorite TV show is on during prime trick-or-treating time. Whatever the case, we think it’s perfectly acceptable to leave a bowl of candy outside the door, especially if there are electronics involved.

In this case, the bowl detects trick-or-treaters and candy eaters using an LD2410 60 GHz radar sensor and an RP2040. A light pipe shows orange when a person is detected, and switches over to green as they come closer, as if to say you may have candy now.

Nothing happens after that, but now that we think about it, it would be cool to add an MP3 decoder and a speaker to play a little witch cackle or something once they’ve had a chance to stick their hand in the bucket.

[Mike Kushnerik] actually designed the PCB a few months ago for non-Halloween purposes: some home automation projects. But then they were trying to think of something for Halloween, and this delightful light-up bucket came to mind. In addition to the RP2040 chip, there’s a 128 MB flash chip, a WS2812 LED, and a header for communicating with the radar sensor over UART. Be sure to check out the brief demo video after the break.

If you’d like to stand outside and give out candy, at least send it down a light-up slide or something.

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This Packable Ham Radio Antenna Is Made From Nothing But Tape

October 13, 2023 by Dan Maloney 46 Comments

On today’s episode of “Will It Antenna?”, [Ben Eadie (VE6SFX)] designs and tests an antenna made entirely of tape, and spoiler alert — it works pretty well.

By way of background, the basic design [Ben] uses here is known as a J-pole, a popular “my first antenna” design for amateur radio operators looking to go beyond the stock whip antenna that comes with that cheap handy-talkie you just can’t resist buying as soon as you get your license. Usually, though, hams will build their J-poles from rigid materials, copper water pipe being a typical choice. Copper has the advantage of being easily sourced, and also results in a self-supporting, weather-resistant antenna that’s easy to mount outdoors. However, copper is getting to be egregiously expensive, and a couple of meters of water pipe isn’t exactly amenable to portable operation, if that’s your jam.

To solve those problems, [Ben] decided to keep his copper use to a minimum with a roll of copper foil tape. He doesn’t provide any specs on the tape, but it looks like it’s about 6 mm (1/4″) wide and judging by a quick Amazon search, probably goes for about $10 a roll. He starts the build with a couple of strips of plain old duck tape — we’ve already had the “duck vs. duct” argument — laid out with the sticky sides together. The copper foil is applied to the duck tape backing using dimensions from any of the J-pole calculators available online. Dimensions are critical to getting good performance from a J-pole, and this is where [Ben]’s tape design shines. Element too long? No problem, just peel up a bit and tear some off. Did you go too far and make an element too short? Easy — just stick on an extension piece of foil. Tuning the location of the feedline connection was a snap, too, with movable terminals held in place with magnets.

Once everything was tuned up, [Ben] soldered down the feed points and covered the foil with a protective layer of duck tape. The antenna performed swimmingly, and aside from costing almost nothing to build, it weighs very little, rolls up to fit in a pack for field operations, and can easily be hoisted into a tree for better coverage. Looks like we’ll be putting in an order for some copper tape and building one of these too. Continue reading “This Packable Ham Radio Antenna Is Made From Nothing But Tape” →

Hackaday Links: October 8, 2023

October 8, 2023 by Dan Maloney 17 Comments

Too much of a good thing is generally a bad thing, but a surfeit of asteroid material is probably a valid exception to that rule. Such was NASA’s plight as it started to unpack the sample return capsule recently dropped off by the OSIRIS-REx spacecraft as it flew by Earth, only to discover it was packed to overflowing with samples of asteroid Bennu. The spacecraft, which arrived at Bennu in 2018 and spent a good long time mapping the near-Earth asteroid, apparently approached its carefully selected landing site a bit too energetically and really packed the sample container full of BennuBits™ — so much so that they could actually see sample shedding off into space before stowing it for the long trip back to Earth. The container is now safely in the hands of the sample analysis team, who noted that everything in the TAGSAM (Touch and Go Sample Acquisition Module), even the avionics deck, is covered with black particles, each precious one of which needs to be collected and cataloged. The black stuff is especially interesting to planetary scientists, as it might be exactly what they were after when they selected Bennu, which may have broken off a much larger carbon-rich asteroid a billion or so years ago. It’ll be interesting to see if these interplanetary hitchhikers have anything to tell us about the origin of life in the solar system.

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The measurement results of: (a) RSSI in dBm collected from gateway 2 and (b) soil moisture during the winter period. (Credit: Maja Škiljo et al., 2022)

Using LoRa Nodes As Soil Moisture Sensing Antennas

October 2, 2023 by Maya Posch 9 Comments

Implementation of LoRaWAN-based soil moisture sensing device. (Credit: Maja Škiljo et al., 2022)

Although we generally think of Internet of Things (IoT) and similar devices as things that are scattered around above ground, there are plenty of reasons to also have such devices underground. These so-called IoUT devices are extremely useful when it comes to monitoring underground structures, but communication via radiowaves is obviously impacted when soil is in the way. Although there are ways to get around this, a 2022 paper by Maja Škiljo and colleagues in Sensors covers an interesting way to make use of this signal attenuation property of changing moisture levels in soil.

By quantifying the exact attenuation of the signal received at the gateways, they were able to determine the soil moisture levels around the LoRa node which had been buried at a depth of approximately 14 centimeters. This LoRa node used off-the-shelf components consisting of an ATmega328P-based Arduino Pro Mini and SX1276-based RFM95W LoRa module with a spring antenna.

During experimentation in- and outdoors it was determined that a narrowband, printed (PCB) antenna was optimal for soil moisture sensing purposes. Other than the interesting question of how to keep soil moisture sensing nodes like this powered up over long periods of time (perhaps periodic retrieval to replenish the battery), this would seem to be a very interesting way to monitor the soil moisture levels in something like a field, where each node can provide its own ID and the received signal providing the relevant data in the form of the SNR and other parameters recorded by the gateway.

(Heading image: The measurement results of: (a) RSSI in dBm collected from gateway 2 and (b) soil moisture during the winter period. (Credit: Maja Škiljo et al., 2022) )

This Week In Security: Magic Packets, GPU.zip, And Enter The Sandman

September 29, 2023 by Jonathan Bennett 4 Comments

Leading out the news this week is a report of “BlackTech”, an Advanced Persistent Threat (APT) group that appears to be based out of China, that has been installing malicious firmware on routers around the world. This firmware has been found primarily on Cisco devices, and Cisco has released a statement clarifying their complete innocence and lack of liability in the matter.

It seems that this attack only works on older Cisco routers, and the pattern is to log in with stolen or guessed credentials, revert the firmware to a yet older version, and then replace it with a malicious boot image. But the real fun here is the “magic packets”, a TCP or UDP packet filled with random data that triggers an action, like enabling that SSH backdoor service. That idea sounds remarkable similar to Fwknop, a project I worked on many years ago. It would be sort of surreal to find some of my code show up in an APT.

Don’t Look Now, But Is Your GPU Leaking Pixels

There’s a bit debate on who’s fault this one is, as well as how practical of an attack it is, but the idea is certainly interesting. Compression has some interesting system side effects, and it’s possible for a program with access to some system analytics to work out the state of that compression. The first quirk being leveraged here is that GPU accelerated applications like a web browser use compression to stream the screen view from the CPU to the GPU. But normally, that’s way too many pixels and colors to try to sort out just by watching the CPU and ram power usage.

And that brings us to the second quirk, that in Chrome, one web page can load a second in an iframe, and then render CSS filters on top of the iframe. This filter ability is then used to convert the page to black and white tiles, and then transform the white tiles into a hard-to-compress pattern, while leaving the black ones alone. With that in place, it’s possible for the outer web page to slowly recreate the graphical view of the iframe, leaking information that is displayed on the page.

And this explains why this isn’t the most practical of attacks, as it not only requires opening a malicious page to host the attack, it also makes some very obvious graphical changes to the screen. Not to mention taking at least 30 minutes of data leaking to recreate a username displayed on the Wikipedia page. What it lacks in practicality, this approach makes up for in cleverness and creativity, though. The attack goes by the GPU.zip moniker, and the full PDF is available. Continue reading “This Week In Security: Magic Packets, GPU.zip, And Enter The Sandman” →

Tech In Plain Sight: Microwave Ovens

September 26, 2023 by Al Williams 31 Comments

Our homes are full of technological marvels, and, as a Hackaday reader, we are betting you know the basic ideas behind a microwave oven even if you haven’t torn one apart for transformers and magnetrons. So we aren’t going to explain how the magnetron rotates water molecules to produce uniform dielectric heating. However, when we see our microwave, we think about two things: 1) this thing is one of the most dangerous things in our house and 2) what makes that little turntable flip a different direction every time you run the thing?

First, a Little History

Westinghouse Powercaster which could, among other things, toast bread in six seconds

People think that Raytheon engineer Percy Spenser, the chief of their power tube division, noticed that while working with a magnetron he found his candy bar had melted. This is, apparently, true, but Spenser wasn’t the first to notice. He was, however, the first to investigate it and legend holds that he popped popcorn and blew up an egg on a colleague’s face (this sounds like an urban legend about “egg on your face” to us). The Raytheon patent goes back to 1945.

However, cooking with radio energy was not a new idea. In 1933, Westinghouse demonstrated cooking foods with a 10 kW 60 MHz transmitter (jump to page 394). According to reports, the device could toast bread in six seconds. The same equipment could beam power and — reportedly — exposing yourself to the field caused “artificial fever” and an experience like having a cocktail, including a hangover on overindulgence. In fact, doctors would develop radiothermy to heat parts of the body locally, but we don’t suggest spending an hour in the device.

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