Microscopic images of E. coli before (left) and after disinfection. The bacteria died quickly after sunlight produced chemicals that caused serious damage to the bacterial cell membranes, as shown in the red circles. (Image credit: Tong Wu/Stanford University)

Generating Hydrogen Peroxide For Disinfecting Water Using A Solar-Driven Catalyst

Ensuring that water is safe to use and consume can be a real chore, especially for those who live in impoverished areas without access to safe drinking water. Here is where researchers at Stanford University hope that their recently developed low-cost catalyst can make a difference. This catalyst comes in the form of nano-sized particles (nanoflakes) consisting out aluminium oxide, molybdenum sulfide, copper and iron oxide. When exposed to sunlight,  the catalyst performs like a photon-sensitive semiconductor/metal junction (Cu-MoS2), with the dislodged electrons going on to react with the surrounding water, resulting in the formation of hydrogen peroxide (H2O2) and hydroxy radicals.

Disinfectant powder is stirred in bacteria-contaminated water (upper left). The mixture is exposed to sunlight, which rapidly kills all the bacteria (upper right). A magnet collects the metallic powder after disinfection (lower right). The powder is then reloaded into another beaker of contaminated water, and the disinfection process is repeated (lower left). (Image credit: Tong Wu/Stanford University)

Waterborne diseases are very common, with even the US reporting 7,000 deaths and 120,000 hospitalizations in 2021, according to the US CDC, and many more affected worldwide. Much of the harm is done by microbes, in particular bacteria such as E. coli, which are prolific in aquatic environments. By using this catalyst powder in contaminated water, the researchers reported that the Escherichia coli colonies in the tested samples were fully eradicated after a 60 second exposure to sunlight.

The reason for this is that hydrogen peroxide and similar reactive oxygen species are highly destructive to living cells, yet they are simultaneously very safe. Because of their high reactivity they are very unstable and thus short-lived. This is useful when the water with the now very dead microbes is consumed afterwards, with the catalyst itself being ferromagnetic and thus easily separated using a magnet.

With this proof of concept in hand, it’d be interesting to see what the product will look like, especially when it comes to the final separation step and making this as easy as possible. Since the catalyst is not consumed or presumably contaminated, it can last pretty much forever, making it an attractive alternative to water purification tablets and expensive filtration systems.

(Heading image: Microscopic images of E. coli before (left) and after disinfection. The bacteria died quickly after sunlight produced chemicals that caused serious damage to the bacterial cell membranes, as shown in the red circles. (Image credit: Tong Wu/Stanford University) )

Where Exactly Did That Network Packet Come From?

Have you ever noticed that some websites can figure out, at least roughly, where you are? Sometimes they use it to find you a closer content provider. Or they might block you from seeing certain things while offering you other things specific to your location. This is possible because there are databases that map IPs to locations. [Mark Litwintschik] looks at using those databases from an API or downloading them into your own database. He also shows some very large database queries, which is interesting, too. He uses IPInfo, although there are other providers. Some only provide a limited number of lookups, but there are plenty of free tiers for low-volume usage.

The database changes every day. Of course, each provider has a different way of getting data, and so there are differences. [Mark] compares the IPInfo dataset against MaxMind’s also free database. That involved comparing over 3 billion records! Actually, the 3 billion are the number of IPs that matched up in both databases. There were an additional 118 million that didn’t match and 34 million that were not in the MaxMind database.

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Fly Like You Drive With This Flying RC Drift Car

So it’s 2023, and you really feel like we should have flying cars by now, right? Well, as long as you ignore the problem of scale presented by [Nick Rehm]’s flying RC drift car, we pretty much do.

At first glance, [Nick]’s latest build looks pretty much like your typical quadcopter. But the design has subtle differences that make it more like a car without wheels. The main difference is the pusher prop at the aft, which provides forward thrust without having to pitch the entire craft. Other subtle clues include the belly-mounted lidar and nose-mounted FPV camera, although those aren’t exactly unknown on standard UAVs.

The big giveaway, though, is the RC car-style remote used to fly the drone. Rather than use the standard two-joystick remote, [Nick] rejiggered his dRehmFlight open-source flight control software to make operating the drone less like flying and more like driving. The lidar is used to relieve the operator of the burden of altitude keeping by holding the drone at about a meter or so off the deck. And the video below shows it doing a really good job of it, for the most part — with anything as complicated as the multiple control loops needed to keep this thing in the air, it’s easy for a sudden input to confuse things.

We have to admit that [Nick]’s creation looks like a lot of fun to fly, or drive — whichever way you want to look at it. Either way, we like the simplification of the flight control system and translating the driving metaphor into flying — it seems like that’ll be something we need if we’re ever to have full-size flying cars.

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Nice Try, But It’s Not Aperture Synthesis

Some of the world’s largest radio telescopes are not in fact as physically large as they claim to be, but instead are a group of telescopes spread over a wide area whose outputs are combined to produce a virtual telescope equal in size to the maximum distance between the constituents of the array. Can this be done on the cheap with an array of satellite dishes? It’s possible, but as [saveitforparts] found out when combining a set of Tailgater portable dishes, not simply by linking together the outputs from a bunch of LNBs.

The video below the break still makes for an interesting investigation and the Tailgater units are particularly neat. It prompted us to read up a little on real aperture synthesis, which requires some clever maths and phase measurement for each antenna. Given four somewhat more fancy LNBs with phase-locked local oscillators and an software-defined radio (SDR) for each one then he might be on to something.

If you’re curious about the cyberdeck in the video, you might like to read our coverage of it. And the Tailgater might be a bit small, but you can still make a useful radio telescope from satellite TV parts.

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Nokia N-Gage QD Becomes Universal Bluetooth Gamepad

The Nokia N-Gage might not have put up much of a fight against Nintendo’s handheld dynasty, but you can’t say it didn’t have some pretty impressive technology for the time. [BeardoGuy] happens to have a perfectly functional N-Gage QD, which he turned into a universal Bluetooth gamepad.

The handheld runs a program that makes it act as a gamepad, and a DIY Bluetooth dongle is required on the client side. The dongle consists of an ATtiny85-based development board and HC-06 Bluetooth module, and will be recognized as a USB gamepad by just about anything it plugs in to.

[BeardoGuy]’s custom GamepadBT program sends button events via Bluetooth to the dongle, and those events are then sent via USB and look just like those from any standard gamepad.

This project can be used as a resource for how to implement a USB gamepad, whether on a Nokia N-Gage or not. You can see all the details at the project’s GitHub repository, and watch it in action in the video embedded below.

As for the Nokia N-Gage itself, one might be interested to know there’s an up-to-date development environment and even Wordle has been ported to the N-Gage. It may look like a relic of the past, but it is far from being forgotten.

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Learning 3D Printing Best Practices From A Pro

It might seem like 3D printing is a thoroughly modern technology, but the fact is, it’s been used in the industry for decades. The only thing that’s really new is that the printers have become cheap and small enough for folks like us to buy one and plop it on our workbench. So why not take advantage of all that knowledge accumulated by those who’ve been working in the 3D printing field, more accurately referred to as additive manufacturing, since before MakerBot stopped making wooden printers?

That’s why we asked Eric Utley, an applications engineer with Protolabs, to stop by the Hack Chat this week. With over 15 years of experience in additive manufacturing, it’s fair to say he’s seen the technology go through some pretty big changes. Hes worked on everything from the classic stereolithography (SLA) to the newer Multi Jet Fusion (MJF) printers, with a recent focus on printing in metals such as Inconel and aluminum. Compared to the sort of 3D printers he’s worked with, we’re basically playing with hot, semi-melted, LEGOs — but that doesn’t mean some of the lessons he’s learned can’t be applied at the hobbyist level. Continue reading “Learning 3D Printing Best Practices From A Pro”

Hackaday Podcast 220: Transparent Ice, Fake Aliens, And Bendy Breadboards

You can join Elliot and Al as they get together to talk about their favorite hacks of the week. There’s news about current contests, fake alien messages, flexible breadboards, hoverboards, low-tech home automation, and even radioactive batteries that could be a device’s best friend.

We have a winner in the What’s that Sound competition last week, which was, apparently, a tough one. You’ll also hear about IC fabrication, FPGAs, and core memory. Lots to talk about, including core memory, hoverboards, and vacuum tubes.

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!

Or download all the things!

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