Discovery Dish Lets You Pick Up The Final Frontier

January 7, 2024 by Tom Nardi 15 Comments

These days, affordable software defined radios (SDRs) have made huge swaths of the spectrum available to hobbyists. Whether you’re looking to sniff the data from that 433 MHz thermometer you’ve got in the backyard or pick up transmissions from satellites, the same little USB-connected box can make it happen.

But even the best SDR is constrained by the antenna it’s connected to, and that’s where it can still get a little tricky for new players. Luckily, there’s a new option for those who want to pick up signals from space without breaking the bank: the Discovery Dish by KrakenRF. After reaching 105% of its funding goal on December 20th, the handy little 65-cm aluminum reflector looks like it’s on track to ship out this summer.

The Discovery Dish was designed from the ground up to enable hobbyists to receive real-time weather data from satellites transmitting in the L band (GOES, NOAA, Meteor, etc.) and experiment with hydrogen line radio astronomy. Neither of which are anything new, of course. But having a pre-built dish and feed takes a lot of the hassle out of picking up these distant signals.

Although the current prototype has a one-piece reflector, the final Discovery Dish will break down into three “petals” to make storage and transport easier. If you don’t want to take it all the way apart, you can simply remove the feed to make it a bit more compact. Speaking of which, KrakenRF is also offering three different feeds depending on what signals you’re after: L band, Inmarsat, or hydrogen line.

You still have options if you’ve got to keep your radio hacking on a tighter budget. As we saw recently, you can actually pull an ET and pick up weather satellites using a foil-lined umbrella. Or spend a little at the big box hardware store and grab some aluminum flashing.

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World’s First Precision Lathe: Indispensable When Constructing The Antikythera Mechanism

January 7, 2024 by Maya Posch 26 Comments

The precision lathe with the hooks, the bowstring, and vise visible as material is being processed. (Credit: Clickspring)

We commonly tend to associate lathes with the Industrial Revolution, when metalworking shifted largely from blacksmiths to machinists, but the use of lathes is much older than that. As [Chris] over at the Clickspring YouTube channel demonstrates in a recent video, small precision lathes were exceedingly common in the Ancient World. Not only is there ample historical evidence of them being used as far back as 1300 BCE in Ancient Egypt, but they’re also the most optimal way to get perfectly round pins and other, more intricate shapes that would be an absolute nightmare to create with just some metal files and chisels.

In the video, [Chris] uses two metal hooks, bent in a ninety-degree angle and clamped down in a vise, tapering towards each other into points. A bow string around a round piece of wood is used to bootstrap a more permanent retention element and bushing for the bow string as it is drawn over the wood to rotate it. Subsequent material that has to be worked on in the lathe is then clamped between the two points. This way, using basic materials that have been around for thousands of years and some muscle power, it’s possible to create a small lathe that can be used to create perfectly symmetrical shapes, such as those used in the construction of the Antikythera Mechanism, which [Chris] has been rebuilding for the past years, using only period-correct tools. He’s learned a lot about the mechanism in the process.

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Hackaday Links: January 7, 2024

January 7, 2024 by Dan Maloney 27 Comments

Oh, perfect — now our cars can BSOD. At least that’s how it looks from a forum post showing a Blue Screen of Death on a Ford Mustang Mach E, warning that an over-the-air software update failed, and now the car can’t be driven. The BSOD includes a phone number to reach Ford’s Customer Relationship Center and even presents a wall of text with specific instructions to the wrecker driver for loading the bricked vehicle onto a flatbed. Forum users questioned the photo’s veracity, but there are reports of other drivers getting bricked the same way. And we’ve got to point out that even though this specific bricking happened to an EV, it could just have easily happened to an ICE vehicle too; forum members were particularly prickly about that point. It would be nice if OTA software updates on vehicles could always roll back to the previous driveable state. Still, we suppose that’s not always possible, especially if memory gets corrupted during the update. Maybe the best defense against a bricked vehicle would be to keep a beater around that doesn’t need updates to keep running.

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Using Sound Waves As A Fire Extinguisher

January 7, 2024 by Maya Posch 15 Comments

In order for a fire to sustain itself, it needs three things: fuel, heat, and oxygen, with the disruption of just one of those causing the fire to extinguish. Water, sand, and carbon dioxide-based fire extinguishers are commonly used, but you’re probably familiar with blowing out a candle using your breath. Counter-intuitively, we also blow on a fire (or use bellows) to make it burn better, so what is happening here? Starting with a novelty app for smartphones that can be used to blow out small flames like candles, [The Action Lab] digs into the topic in a recent video.

Using an air vortex cannon strapped to a bass reflex port to wiggle a flame to death. (Credit: The Action Lab)

Using a fairly beefy speaker to blast a 70 Hz tone at a big alcohol flame was not enough to extinguish it, but using the bass reflex port on the back was more effective, yet still not nearly enough. Using an air vortex cannon to focus the sound waves from the bass reflex port, it ‘wiggles’ the flame out in a matter of seconds, as illustrated with a thermal camera. Compared to the much stronger airflow from the box fan that was also used in one attempt, the difference with the sound waves is that they oscillate, constantly fluctuating the air pressure.

This churns the air and thus the flame around, diffusing the suspended fuel, cooling the air, and alternatingly pushing oxygenated air and carbon dioxide-heavy combustion fumes into the flame. This differs from the constant flow from the box fan, which only pushes oxygen-rich air into the flame, thus keeping it intact and burning brightly. Perhaps the main question that remains here is just how practical this approach is for extinguishing flames. Some commentators suggested using this approach in low- and zero-gravity situations, as found in space stations, where regular fire extinguishers based around smothering a flame aren’t as practical.

(Thanks to [Hyperific] for the tip)

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Recreating The Jupiter ACE

January 7, 2024 by Al Williams 25 Comments

What looks like a Sinclair ZX81 but runs Forth? If you said a Jupiter ACE, you get a gold star. These are rare because ordinary people in 1982 didn’t want Forth, so only about 5,000 of the devices were sold. [Cees Meijer] assumes they are unaffordable, so he built a replica and shows you how you can, too. [Scott Baker] built one recently; you can see his video below.

The resemblance to the Sinclair computer wasn’t just a coincidence. Richard Altwasser and Steven Vickers were behind the computer, and both had worked for Sinclair previously. In addition to being famous for using Forth, the machine initially had a badly manufactured case and an unreliable keyboard. A later version tried to correct these issues, but there were fewer than 1,000 made. [Cees’] replica used a design from [Grant Searle] with some modifications.

We liked the realistic look of the 3D printed keyboard. The keyboard uses white plastic with raised letters. A quick black spray paint followed by sanding gives the appearance of black keys with white printed text.

Overall, this is a good-looking build of a computer you probably won’t see in person. We wish Forth had caught on in the early PC world, but it didn’t. [Grant] was prolific with replica computers, and [Cees] isn’t the only one who used that work as a starting point for their own projects. If you want real old-school Forth, you have to go back a few more years.

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Remote-Control Kinetic Sand Table Uses A Single Arduino

January 7, 2024 by Kristina Panos 11 Comments

There’s nothing fun about a Sisyphean task unless you’re watching one being carried out by someone or something else. In that case, it can be mesmerizing like this Arduino-driven kinetic sand table.

What you can’t see. Image via [thang010146] on YouTube

Like many of these builds, it all started with an ordinary coffee table from the hacker’s favorite furnitüre store. [NewsonsElectronics] opened it up and added a 3mm-thick board to hold the sand and another to hold the rails and magnets.

After designing some pieces to connect the rails and pulleys together, [NewsonsElectronics] let the laser cutter loose on some more 3mm stock. A pair of stepper motors connected to a CNC shield do all of the work, driving around a stack of magnets that causes the ball bearing to trudge beautifully through the sand.

Be sure to check out the videos after the break. The first is a nice demonstration, and the second is the actual build video. In the third video, [NewsonsElectronics] explains how they could write the world’s smallest GRBL code to swing this with a single Arduino. Hint: it involves removing unnecessary data from the g-code generated by Sandify.

Don’t have a laser cutter? Here’s a sand table built from 3D printer parts.

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802.11ah Wi-Fi HaLOW: The 1 Kilometer WiFi Standard

January 7, 2024 by Maya Posch 29 Comments

The 802.11ah WiFi (HaLow) standard is fairly new, having only been introduced in 2017. It’s supposed to fall somewhere between standard WiFi used in domiciles and offices and the longer range but low-bitrate LoRaWAN, ZigBee, and others, with bandwidth measured in megabits per second. In a recent video, [Ben Jeffery] looks at the 802.11ah chipsets available today and some products integrating these.

The primary vendors selling these chipsets are TaiXin Semiconductor (TXW8301), Morse Micro (MM6108), and Newracom (NRC7394), with a range of manufacturers selling modules integrating these. Among the products using these, [Ben] found an Ethernet range extender kit (pictured) that takes 12V input as power, along with Ethernet. Running some distance tests in a quarry showed that 300 meters was no problem getting a strong signal, though adding some trees between the two transceivers did attenuate the signal somewhat.

Another interesting product [Ben] tested is what is essentially an 802.11ah-based WiFi extender, using an 802.11ah link between the server node – with an Ethernet socket – and a client that features a standard 2.4 GHz 802.11n that most WiFi-enabled devices can connect to. Using this, he was able to provide a solid ~10 Mbps link to a cabin near the main house (~10 meters) through two outside walls. What makes 802.11ah so interesting is that it is directly compatible with standard Ethernet and WiFi protocols and uses the 900 MHz spectrum, for which a wide range of alternative antennae exist that can conceivably extend the range even more.

(Thanks to [Keith Olson] for the tip)

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