You Can Build Your Own Sushi Train

According to [Garage Avenger], in Norwegian culture it’s considered impolite to ask for things to be passed across a dinner table, so much standing and reaching is the course of the day. To assist in reducing the effort required, he set about building his own sushi train device to solve the problem, giving equal condiment access to all!

The system is capable of taking plenty of weight from heavy dinner bowls, altogether quite different than relatively-light sushi dishes on plastic plates.

The system is actually relatively simple, relying on a Wemos D1 Mini controlled by a Blynk app to run the show. Mechanically, a large drive gears is turned by a stepper motor to drive the wooden conveyor chain that actually makes up the “sushi train.” The chain links ride on a bed of Norwegian one krone coins acting as rollers.

The result is a working table-sized sushi train that really does carry plates around well. It didn’t stop people leaning over [Garage Avenger] at the dinner table, but it makes a great centerpiece on the dinner table for sharing dishes like tacos.

We’ve seen similar table technology, the Lazy Susan, around these parts before. Video after the break.
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A Wireless Headphone Charger Without The Wireless

We’re all used to the idea of wireless charging, usually in the form of an induction coil on which a mobile phone or other appliance can be placed for a top-up. Not every battery-powered appliance has a built-in wireless charging coil though, meaning that despite the tech being available we all still have a jumble of wires.

[Sergio Costas] has a simple solution to conjuring wireless charging from thin air in his headphone stand, which conceals a set of charging contacts. It’s by no means a new idea and it might seem like an obvious hack, but it undeniably does away with the wires and we like it. After all, if it were that obvious, none of us would have that mess of chargers.

The headphones in question are a Bluetooth wireless pair, and the charging contacts have been brought out via a voltage regulator and a bridge rectifier to a pair of copper tapes along the sides of the headband. These mate with matching contacts in a 3D printed holder to which 12 VDC has been applied. Perhaps he’s just reinvented the springy contacts you’ll find on any cordless home phone, but it’s unquestionably a charger without wires.

Meanwhile if you have a conventional wireless charger, how do you know it’s working?

The Metal 3D Printing Hack Chat Brings The Heat

At this point, it’s safe to say the novelty of desktop 3D printing has worn off. The community has largely come to terms with the limitations of extruded plastics, and while we still vehemently believe that it’s a transformative technology, we’ll admit there aren’t too many applications where a $200 USD printer squirting out PLA is truly the best tool for the job.

But rather than looking at today’s consumer 3D printer market as the end of the line, what if it’s just the beginning? With the problems of slicing, motion control, and extrusion more or less solved when it comes to machines that print in plastic, is it finally time to turn our attention to the unique problems inherent in building affordable metal printers? Agustin Cruz certainly thinks so, which is why he took to the Hack Chat this week to talk about his personal vision for an open source 3D printer that can turn powdered metals into solid objects by way of a carefully controlled electron beam.

To be clear, Agustin isn’t suggesting you toss out your Creality anytime soon. Metal 3D printing will always be a niche within a niche, but for applications where even advanced engineering plastics like PEI and PEEK simply won’t do, he argues the community needs to have a cheap and accessible option. Especially for developing and low income countries where traditional manufacturing may be difficult. The machine he’s been working on wouldn’t be outside the capabilities of an individual to build and operate, but at least for right now the primary target is hospitals, colleges, and small companies.

The Chat was full of technical questions about Agustin’s design, and he wasn’t shy about tackling them. Some wondered why he decided to sinter the metal powder with an electron gun when solid-state lasers are cheap, easily available, and relatively straightforward to work with. But while the laser might seem like the easier solution on the surface, Agustin points out that using a magnetically focused electron beam gives his printer some unique capabilities.

For example, he can easily defocus the beam and pass it over the entire build plate to pre-heat the powder. The steerable beam doesn’t require mirrors either, which not only reduces the weight and complexity of the machine, but in theory should allow for faster print speeds. The beam can be moved in the X/Y dimensions with an accuracy of 0.01 mm, and while the beam diameter is currently a respectable 0.5 mm, Agustin says he’s working on bringing that down to 0.1 mm for high detail work. The temperature at the focal point of the beam is between 1,400 and 1,500 °C, which he notes is not only hot enough to melt the powdered metal, but can also weld stainless steel.

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Hackaday Podcast 159: Zombie Killer Or Rug Maker, 3D Printed Rims, 1950s Drum Machines, And Batteries On Wheels

Join Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi as they look back on the best hacks and stories of the previous week. There’s plenty in the news to talk about, though between faulty altimeters and the ongoing conflict in Ukraine, it isn’t exactly of the positive variety. But things brighten up quickly as discussion moves on to 3D printed car wheels, a fantastically complex drum machine from 1958, a unique take on the seven-segment flip display, and a meticulously designed (and documented) coffee machine upgrade. Somewhere in there a guy also recreates a rare German anti-air rocket launcher from WWII, but it’s all in the name of history. We’ll also tackle two very different forms of electric propulsion, from the massive wheeled batteries popping up in garages and driveways all over the world to high-efficiency thrusters for deep space missions.

Direct Download (~60 MB)

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Boat Anchor Twins Get A Little Digital Help Staying On Frequency

In the ham radio trade, gear such as the old Drake units [Dr. Scott M. Baker] has in his radio shack are often referred to as “boat anchors.” It refers to big, heavy radios that were perhaps a bit overengineered compared to the state of the art at the time they were designed, and it’s actually a shame that the name has taken on something of a pejorative connotation, since some of this gear is rock solid half a century or more after it was built.

But older gear is often harder to use, at least compared to the newer radios with microcontrollers and more stable oscillators inside. To make his 1970s-era Drake “Twins” setup of separate but linked receiver and transmitter a little more fun to use, [Scott] came up with this neat Raspberry Pi-based DDS-VFO project to keep his boat anchors afloat. Compared to the original mechanically tuned variable frequency oscillator in the Drake receiver, the direct-digital synthesis method promises more stability, meaning less knob-nudging to stay on frequency.

The hardware used for the DDS-VFO is actually pretty simple — just a Raspberry Pi Zero W driving an AD9850-based signal-generator module. Sending the signal to the Twins was another matter. That was done by tapping into the injection cable linking both units, which meant a few circuit complications to deal with signal attenuation. [Scott] also added amenities like a digital frequency display, optical encoder with crank-style knob to change frequency, and a host of Cherry MX keyswitches for quick access to different features.

From the look of the video below, the Twins are now rock-solid and a lot easier to use. This project is loosely based on a recent panadapter project [Scott] undertook for the receiver side of the Twins.

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This Week In Security: DDoS Techniques, Dirty Pipe, And Lapsus$ Continued

Denial-of-Service (DoS) amplification. Relatively early in the history of the Internet — it was only 14 years old at the time — the first DoS amplification attack was discovered. [TFreak] put together smurf.c, likely in 1997, though it’s difficult to nail the date down precisely.

The first real DoS attack had only happened a year before, in 1996. Smurf worked by crafting ICMP packets with spoofed source addresses, and sending those packets to a network’s broadcast address. A host that received the request would send the packet to the target, and if multiple hosts responded, you got a bigger DoS attack for free. Fast forward to 1999, and the first botnet pulled off a Distributed DoS, DDoS, attack. Ever since then, there’s been an ongoing escalation of DDoS traffic size and the capability of mitigations.

DNS and NTP quickly became the popular choice for amplification, with NTP requests managing an amplification factor of 556, meaning that for every byte an attacker sent, the amplifying intermediary would send 556 bytes on to the victim. You may notice that so far, none of the vulnerable services use TCP. The three-way handshake of TCP generally prevents the sort of misdirection needed for an amplified attack. Put simply, you can’t effectively spoof your source address with TCP.

There are a pair of new games in town, with the first being a clever use of “middleboxes”, devices like firewalls, Intrusion Prevention Systems, and content filters. These devices watch traffic and filter content or potential attacks. The key here is that many such devices aren’t actually tracking TCP handshakes, it would be prohibitively memory and CPU intensive. Instead, most such devices just inspect as many packets as they can. This has the unexpected effect of defeating the built-in anti-spoofing of TCP.

An attacker can send a spoofed TCP packet, no handshake required, and a vulnerable middlebox will miss the fact that it’s spoofed. While that’s interesting in itself, what’s really notable is what happens when the packet appears to be a request for a vulnerable or blocked resource. The appliance tries to interrupt the stream, and inject an error message back to the requester. Since the requestor can be spoofed, this allows using these devices as DDoS amplifiers. As some of these services respond to a single packet with what is essentially an entire web page to convey the error, the amplification factor is literally off the charts. This research was published August 2021, and late February of this year, researchers at Akamai have seen DDoS attacks actually using this technique in the wild.

The second new technique is even more alien. Certain Mitel PBXs have a stress-test capability, essentially a speed test on steroids. It’s intended to only be used on an internal network, not an external target, but until a recent firmware update that wasn’t enforced. For nearly 3,000 of these devices, an attacker could send a single packet, and trigger the test against an arbitrary host. This attack, too, has recently been seen in the wild, though in what appears to be test runs. The stress test can last up to 14 hours at worst, leading to a maximum amplification factor if over four billion, measured in packets. The biggest problem is that phone systems like these a generally never touched unless there’s a problem, and there’s a decent chance that no one on site has the login credentials. That is to say, expect these to be vulnerable for a long time to come. Continue reading “This Week In Security: DDoS Techniques, Dirty Pipe, And Lapsus$ Continued”

Is Your Tape Dispenser Radioactive?

Do you have anything radioactive in your house? Most people will say no, but they are probably wrong. A host of things ranging from glow-in-the dark timepieces to smoke detectors have some amount of radioactivity. But as [Wheeler Scientific] points out, so do some old Scotch tape dispensers. You can watch the video, below.

The dispenser in question is the C-15 which was very common around offices, military bases, and homes for years. They were made up until the 1980s. You have to wonder why a tape dispenser would be radioactive, and [Wheeler] has the explanation.

When you pull tape from the dispenser, you don’t want the dispenser to slide around the desk, so it needs to be heavy. But no one wants to have a giant dispenser nor do you want to pay for one made from a dense metal. So the plastic dispenser contains a ballast to make it heavier. In the case of the C-15 that ballast is thorium-containing monazite sand. A vintage counter shows the radioactivity which isn’t much, of course, but still way less than the ordinary sand used in newer models. You can also see in the video that the material is paramagnetic.

Monazite used to be a primary source of lanthanides but getting rid of the thorium led to alternate sources in the 1960s although it is still used as an ore for thorium. We know some lenses are radioactive. If you want to search your home for radioactivity and you don’t have a Geiger counter, you don’t need much to build one.

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