Localizing Fireworks Launches With A Raspberry Pi

December 30, 2023 by Lewin Day 103 Comments

If you have multiple microphones in known locations, and can determine the time a sound arrives at each one, you can actually determine the location that sound is coming from. This technique is referred to as sound localization via time difference of arrival. [Kim Hendrikse] decided to put the technique to good use to track down the location of illicit fireworks launches.

The build is based on the Raspberry Pi, with [Kim] developing an “autonomous recording unit” complete with GPS module for determining their location and keeping everything time synchronized. By deploying a number of these units, spread out over some distance, it’s possible to localize loud sounds based on the time stamps they show up in the recording on each unit.

Early testing took place with an air horn and four recording units. [Kim] found that the technique works best for sounds made within the polygon. Determining the location was achieved with a sound investigation tool called Raven Lite, developed by Cornell University. The process is very manual, involving hunting for peaks in sound files, but we’d love to see a version that automated comparing sound peaks across many disparate recording units. In any case, it worked incredibly well for [Kim] in practice. Later testing with friends and a network of six recorders spread over Limburg, Netherlands, [Kim] was later able to localize fireworks launches with an accuracy down to a few meters.

Similar techniques are used to locate gunshots, and can work well with pretty much any loud noise that’s heard over a great distance. If you’ve been using your hacker skills to do similar investigative work, don’t hesitate to let us know on the tipsline!

37C3: When Apple Ditches Lightning, Hack USB-C

December 30, 2023 by Elliot Williams 11 Comments

[Thomas Roth], aka [Ghidraninja], and author of the [Stacksmashing] YouTube channel, investigated Apple’s Lightning port and created a cool debugging tool that allowed one to get JTAG on the device. Then, Apple went to USB-C for their new phones, and all his work went to waste. Oh well, start again — and take a look at USB-C.

Turns out, though, that the iPhone 15 uses the vendor-defined messages (VDM) capability of USB-PD to get all sorts of fun features out. Others had explored the VDM capabilities on Mac notebooks, and it turns out that the VDM messages on the phone are the same. Some more fiddling, and he got a serial port and JTAG up and running. But JTAG is locked down in the production devices, so that will have to wait for an iPhone 15 jailbreak. So he went poking around elsewhere.

He found some other funny signals that turned out to be System Power Management Interface (SPMI), one of the horribly closed and NDA-documented dialects owned by the MIPI Alliance. Digging around on the Interwebs, he found enough documentation to build an open-source SPMI plugin that he said should be out on his GitHub soon.

The end result? He reworked his old Lightning hardware tool for USB-C and poked around enough in the various available protocols to get a foothold on serial, JTAG, and SPMI. This is just the beginning, but if you’re interested in playing with the new iPhone, this talk is a great place to start. Want to know all about USB-C? We’ve got plenty of reading for you.

37C3: You Think It’s Bad With Pluto? A History Of The Planets

December 30, 2023 by Elliot Williams 28 Comments

Not every talk at the Chaos Communication Congress is about hacking computers. In this outstanding and educational talk, [Michael Büker] walks us through the history of our understanding of the planets.

The question “What is a planet?” is probably more about the astronomers doing the looking than the celestial bodies that they’re looking for. In the earliest days, the Sun and the Moon were counted in. They got kicked out soon, but then when we started being able to see asteroids, Ceres, Vesta, and Juno made the list. But by counting all the asteroids, the number got up above 1,200, and it got all too crazy.

Viewed in this longer context, the previously modern idea of having nine planets, which came about in the 1960s and lasted only until 2006, was a blip on the screen. And if you are still a Pluto-is-a-planet holdout, like we were, [Michael]’s argument that counting all the Trans-Neptunian Objects would lead to madness is pretty convincing. It sure would make it harder to build an orrery.

His conclusion is simple and straightforward and has the ring of truth: the solar system is full of bodies, and some are large, and some are small. Some are in regular orbits, and some are not. Which we call “planets” and which we don’t is really about our perception of them and trying to fit this multiplicity into simple classification schemas. What’s in a name, anyway?

Quivering Facehugger Is All Geared Up

December 30, 2023 by Donald Papp 4 Comments

[Jason Winfield] shared with us a video describing a project with a lot of personality: a mounted, lit, and quivering Alien facehugger triggered by motion. The end result is a delightful jump scare, and the Raspberry Pi that controls everything also captures people’s reactions.

It starts with a little twitch when motion is sensed, then launches into a perfectly unsettling quiver combined with light and sound. We particularly like the wave-like effect from the LED lighting, which calls to mind illumination from rotating hazard beacons.

The unit looks like a mounted and tastefully-lit static model, but is actually primed to sense motion.

One challenge was how to efficiently move the legs. Rather than use a motor for each limb, [Jason] settled on a single motor driving a rotating cam arrangement. You can see the results for yourself in the video below, but getting there was not simple.

The surplus motor [Jason] chose is thin and high-torque, but runs extremely fast. Since he wanted the legs to quiver creepily rather than vibrate, something needed to be done to mitigate this.

The solution is a planetary gear assembly that drives a rotating ring and cam arrangement coupled to the facehugger’s legs. There’s only one motor, but the effect is that each leg’s motion is independent of the others. The whole assembly is quite slim, and everything is contained within the frame.

Facehuggers and gear assemblies are not exactly an everyday combination, but believe it or not this isn’t the first time the two have joined forces. Check out the Aliens-themed cuckoo clock, complete with crew member torso and emerging chestburster!

Continue reading “Quivering Facehugger Is All Geared Up” →

How To Build A Small Solar Power System

December 30, 2023 by Jenny List 41 Comments

We live in an exciting time with respect to electrical power, one in which it has never been easier to break free from mains electricity, and low-frequency AC power in general. A confluence of lower-power appliances and devices using low-voltage external switch-mode supplies, readily available solar panels and electronic modules, and inexpensive high-capacity batteries, means that being your own power provider can be as simple as making an online order.

But which parts should you choose? Low Tech Magazine has the answer, in the form of a guide to building a small solar power system. The result is an extremely comprehensive guide, and though it’s written for a general audience there’s still plenty of information for the Hackaday reader.

Perhaps the most important part is that it’s demystifying the subject, there in front of us are a set of pretty straightforward recipes for personal power. The computer this is being written on spends a significant proportion of its time on the road with the ever-present company of a very hefty USB-C power pack for example, and the realization that a not-too-expensive solar panel and USB PD source could lessen the range anxiety and constant search for a train seat with a socket for a writer on the move is quite a powerful one.

Take a look and see whether your life could use bit of inexpensive off-grid power, meanwhile we’re quite pleased that the USB-C PD standard has eased some of the DC problems we expressed frustration at back in 2016.

Peltier Mini Fridge For Class By Class

December 30, 2023 by Al Williams 13 Comments

How do you keep a few sodas in your classroom cool? Well, if you are teacher [Ethan Hunt], you have your students design and build a solid-state mini refrigerator that can beat his prototype fridge. The prototype uses a Peltier effect module to get three cans down to 11 C (52 F), with a final goal of reaching 5 C (41 F). It’s not all fun and games either — [Ethan] provides a suggested lesson plan with a total of thirteen modules made to fit in an hour each.

Peltier effect modules, also known as solid-state heat pumps, used to be exotic tech but are now quite common. They are actually the reverse of the Kelvin effect. Thermocouples exploit the Kelvin effect by measuring current flowing due to temperature differences.

Solid-state heat pumps use current flowing to create a comparable temperature difference. However, that’s also the catch. One side of the heat pump gets cold, but the other side gets equally hot. That heat has to go somewhere. The same is true, of course, of a “real” refrigerator or an air conditioner.

The lessons would be perfect to adapt for a class, a kid’s club, or even homeschooling. We’d love to see what your students build. You probably won’t be making liquid nitrogen with this setup. But we have seen more than one mini-fridge.