Hackaday Podcast Episode 251: Pluto, Pinball, Speedy Surgery, And DIY GPS

Welcome to 2024! This time around, Elliot and Dan ring in a new year of awesome hacks with quite an eclectic mix. We kick things off with a Pluto pity party and find out why the tiny ex-planet deserved what it got. What do you do if you need to rename a bunch of image files? You rope a local large-language model in for the job, of course. We’ll take a look at how pinball machines did their thing before computers came along, take a fractal dive into video feedback, and localize fireworks with a fleet of Raspberry Pi listening stations. Ever wonder what makes a GPS receiver tick? The best way to find out might be to build one from scratch. Looking for some adventure? A ride on an electroluminescent surfboard might do, or perhaps a DIY “Vomit Comet” trip would be more your style. And make sure you stick around for our discussion on attempts to optimize surgery efficiency, and our look back at 2023’s top trends in the hardware world.

 

Grab a copy for yourself if you want to listen offline.

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DIY Chemistry Points The Way To Open Source Blood Glucose Testing

Every diabetic knows that one of the major burdens of the disease is managing supplies. From insulin to alcohol wipes, diabetes is a resource-intensive disease, and running out of anything has the potential for disaster. This is especially true for glucose test trips, the little electrochemical dongles that plug into a meter and read the amount of glucose in a single drop of blood.

As you might expect, glucose test strips are highly proprietary, tightly regulated, and very expensive. But the chemistry that makes them work is pretty simple, which led [Markus Bindhammer] to these experiments with open source glucose testing. It’s all part of a larger effort at developing an open Arduino glucometer, a project that has been going on since 2016 but stalled in part thanks to supply chain difficulties on the chemistry side, mainly in procuring glucose oxidase, an enzyme that oxidizes glucose. The reaction creates hydrogen peroxide, which can be measured to determine the amount of glucose present.

With glucose oxidase once again readily available — from bakery and wine-making suppliers — [Markus] started playing with the chemistry. The first reaction in the video below demonstrates how iodine and starch can be used as a reagent to detect peroxide. A tiny drop of glucose solution turns the iodine-starch suspension a deep blue color in the presence of glucose oxidase.

While lovely, colorimetric reactions such as these aren’t optimal for analyzing blood, so reaction number two uses electrochemistry to detect glucose. Platinum electrodes are bathed in a solution of glucose oxidase and connected to a multimeter. When glucose is added to the solution, the peroxide produced lowers the resistance across the electrodes. This is essentially what’s going on in commercial glucose test strips, as well as in continuous glucose monitors.

Hats off to [Markus] for working so diligently on this project. We’re keenly interested in this project, and we’ll be following developments closely. Continue reading “DIY Chemistry Points The Way To Open Source Blood Glucose Testing”

Current-Based Side-Channel Attacks, Two Ways

Funny things can happen when a security researcher and an electronics engineer specializing in high-speed circuits get together. At least they did when [Limpkin] met [Roman], which resulted in two interesting hardware solutions for side-channel attacks.

As [Limpkin] relates it, the tale began when he shared an office with [Roman Korkikian], a security researcher looking into current-based attacks on the crypto engine inside ESP32s. The idea goes that by monitoring the current consumption of the processor during cryptographic operations, you can derive enough data to figure out how it works. It’s difficult to tease a useful signal from the noise, though, and [Roman]’s setup with long wire runs and a noisy current probe wasn’t helping at all. So [Limpkin] decided to pitch in.

The first board he designed was based on a balun, which he used to isolate the device under test from the amplification stage. He found a 1:8 balun, normally used to match impedances in RF circuits, and used its primary as a shunt resistance between the power supply — a CR1220 coin cell — and the DUT. The amplifier stage is a pair of low-noise RF amps; a variable attenuator was added between the amp stages on a second version of the board.

Board number two took a different tack; rather than use a balun, [Limpkin] chose a simple shunt resistor with a few twists. To measure the low-current signal on top of the ESP32’s baseline draw would require such a large shunt resistor that the microcontroller wouldn’t even boot, so he instead used an OPA855 wideband low-noise op-amp as an amplified shunt. The output of that stage goes through the same variable attenuator as the first board, and then to another OPA855 gain stage. The board is entirely battery-powered, relying on nice, quiet 18650s to power both the DUT and the shunt.

How well does it work? We’ll let you watch the talk below and make up your own mind, but since they’ve used these simple circuits to break a range of different chips, we’d say this approach a winner.

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Keeping Watch Over The Oceans With Data Buoys

When viewed from just the right position in space, you’d be hard-pressed to think that our home planet is anything but a water world. And in all the ways that count, you’d be right; there’s almost nothing that goes on on dry land that isn’t influenced by the oceans. No matter how far you are away from an ocean, what’s going on there really matters.

But how do we know what’s going on out there? The oceans are trackless voids, after all, and are deeply inhospitable to land mammals such as us. They also have a well-deserved reputation for eating anything that ventures into them at the wrong time and without the proper degree of seafarer’s luck, and they also tend to be places where the resources that run our modern technological society are in short supply.

Gathering data about the oceans is neither cheap nor easy, but it’s critically important to everything from predicting what the weather will be next week to understanding the big picture of what’s going on with the climate. And that requires a fleet of data buoys, outnumbering the largest of the world’s navies and operating around the clock, keeping track of wind, weather, and currents for us.

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Hackaday Links: December 24, 2023

Back near the beginning of the current Solar Cycle 25, we penned an article on what the whole deal is with solar cycles, and what could potentially lie in store for us as the eleven-year cycle of sunspot population developed. Although it doesn’t really come across in the article, we remember being somewhat pessimistic about things, thinking that Solar Cycle 25 would be somewhat of a bust in terms of increased solar activity, given that the new cycle was occurring along with other, longer-period cycles that tend to decrease solar output. Well, looks like we couldn’t have gotten that more wrong if we tried, since the Sun lashed out with a class X solar flare last week that really lit things up. The outburst came from a specific sunspot, number 3514, and clocked in at X2.8, the most powerful flare since just before the end of the previous solar cycle. To put that into perspective, X-class flares have a peak X-ray flux of 10-4 watts/m², which when you think about it is a lot of energy. The flare resulted in a strong radio blackout; pretty much everything below 30 MHz was unusable for a while.

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Mega-CNC Router Carves Styrofoam Into A Full-Size Flying Delorean

When you own an enormous CNC router, you’ve got to find projects that justify it. So why not shoot for the sky — literally — and build the 1980s-est possible thing: a full-scale flying Delorean.

Attentive readers will no doubt remember [Brian Brocken] from his recent attempt to bring a welding robot out of retirement. That worked quite well, and equipped with a high-speed spindle, the giant ABB robot is now one of the biggest CNC routers we’ve ever seen. As for the flying Delorean, short of the well-known Mr. Fusion mod, [Brian] had to settle for less fictional approaches. The project is still in its early phase, but it appears that the flying car will basically be a huge quadcopter, with motors and propellers hidden under the chassis. That of course means eschewing the stainless steel of the OEM design for something lighter: expanded polystyrene foam (EPS).

The video below shows the fabrication of most of the body, which starts as large blocks of EPS and ends up as shaped panels and an unthinkable amount of dust. Individual pieces are glued together with what looks like plain old PVA adhesive. The standard Delorean “frunk” has been replaced by a louvered assembly that will act as an air intake; we presume the rear engine cover will get the same treatment. Interestingly, the weight of the finished model is almost exactly what Fusion 360 predicted based on the 3D model — a mere 13.9 kg.

[Brian] is currently thrust-testing motors and propellers and has some interesting details on that process in his write-up. There’s obviously a lot of work left on this project, and a lot more dust to be made, and we’ll be eagerly following along. Continue reading “Mega-CNC Router Carves Styrofoam Into A Full-Size Flying Delorean”

Open Source DC UPS Keeps The Low-Voltage Gear Going

We all like to keep our network gear running during a power outage — trouble is, your standard consumer-grade uninterruptible power supply (UPS) tends to be overkill for routers and such. Their outlet strips built quickly get crowded with wall-warts, and why bother converting from DC to AC only to convert back again?

This common conundrum is the inspiration for [Walker]’s DC UPS design, which has some interesting features. First off, the design is open source, which of course invites tinkering and repurposing. The UPS is built for a 12 volt supply and load, but that obviously can be changed to suit your needs. The battery bank is a 4S3P design using 18650 cells, and that could be customized as well. There’s an ideal diode controller that prevents DC from back-feeding into the supply when the lights go out, and a really interesting synchronous buck-boost converter in place of the power management chip you’d normally see in a UPS. The converter chip takes a PWM signal from an RP2040; there’s also an ESP32 onboard for web server and UI duties as well as an STM32 to run the BMS. The video below discusses the design and shows a little of the build.

We’ve seen a spate of DC UPS designs lately, some more elaborate than others. This one has quite a few interesting chips that most of us don’t normally deal with, and it’s nice to see how they’re used in a practical design.

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