2026-04-20 19:00:25
We’ve always been interested in fluidic computers, a technique that uses moving fluids to perform logic operations. Now, Spectrum reports that researchers have developed an electronics-free contact lens that monitors glaucoma and can even help treat it.
The lens is made entirely of polymer and features a microfluidic sensor that can monitor eye pressure in real time. It also has pressure-activated drug reservoirs that dispense medicine when pressure exceeds a fixed threshold. You can see Spectrum’s video on the device below.
This isn’t the first attempt to treat glaucoma, which affects more than 80 million people, with a contact lens. In 2016, Triggerfish took a similar approach, but it used electronic components in the lens, which poses problems for manufacturing and for people wearing them.
Naturally, the device depends on 3D printed molds to create channels and reservoirs in the lens. A special silk sponge in the reservoirs can absorb up to 2,700 times its weight. One sponge holds a red fluid that is forced by pressure into a serpentine microchannel. A phone app uses a neural network to convert the image of the red fluid into a pressure reading.
Two more sponges hold drugs that release at a given pressure determined by the width of the associated microchannel. This allows the possibility of increasing the dose at a higher pressure or even delivering two drugs at different pressure levels.
It is fairly hard to hack your own contact lenses, although we’ve seen it at least once. But smart contacts are not as rare as you might think.
2026-04-20 16:00:35
Nuclear batteries are pretty simple devices that are conceptually rather similar to photovoltaic (PV) solar, just using the radiation from a radioisotope rather than solar radiation. It’s also possible to make your own nuclear battery, with [Double M Innovations] putting together a version that uses standard PV cells combined with small tritium vials as radiation source.
The PV cells are the amorphous type, rated for 2.4 V, which means that they’re not too fussy about the exact wavelength at the cost of some general efficiency. You generally find these on solar-powered calculators for this reason. Meanwhile the tritium vials have an inner coating of phosphor so they glow. With a couple of these vials sandwiched in between two amorphous cells you thus have technically something that you could call a ‘nuclear battery’.
With an approximately 12 year half-life, tritium isn’t amazingly radioactive and thus the glow from the phosphor is also not really visible in daylight. With this DIY battery wrapped up in aluminium foil to cover it up fully, it does appear to generate some current in the nanoamp range, with a single-cell and series voltage of about 0.5 V.
A 170 VAC-rated capacitor is connected to collect some current over time, with just under 3 V measured after a night of charging. In how far the power comes from the phosphor and how much from sources like thermal radiation is hard to say in this setup. However, if you can match up the PV cell’s bandgap a bit more with the radiation source, you should be able to pull at least a few mW from a DIY nuclear battery, as seen with commercial examples.
This isn’t the first time we’ve seen this particular trick. A few years ago, a similar setup was used to power a handheld game, as long as you don’t mind waiting a few months for it to charge.
2026-04-20 13:00:44
We wouldn’t be surprised if you’d never seen the Spira before. The lightweight three-wheel vehicle is closer to a go-kart than a traditional car, and that’s before you even get to the foam body panels. But even the most niche of products enjoys a certain fandom, and [Matt Spears] certainly seems to love working on his Spira. His latest video documents the new modifications he’s made to the car in an effort to ride it on abandoned railroad tracks in the western United States.
His first attempt at riding the rails worked pretty well but he hit an obstruction at high speed which destroyed his front axle and damaged a few other parts on the vehicle, which gave him a perfect excuse to make some upgrades. He swapped the old rear axle out with one from a go-kart, complete with custom wheels and a new braking system. The drivetrain received an upgrade with a 5 kW electric motor, and although [Matt] planned on casting new wheels for the higher speeds, the chemicals he needed didn’t arrive in time. So, to test the new vehicle he repurposed some old wheels just to get the Spria back out on the tracks.
The test run went so well that [Matt] ended up pushing the vehicle farther than he had ever been on this abandoned rail, including over a questionable trestle and far out into the wilderness. Hopefully we’ll see more videos of [Matt] taking this car to explore even more remote places. In the meantime, take a look at some simpler, non-electric vehicles that are often used to explore abandoned rail lines in California.
2026-04-20 10:00:15
Most makers find themselves in need of a benchtop power supply at some point or another. Basic models can be had relatively cheaply, but as your current demands go higher, so does the price. [Danilo Larizza] has figured out an alternative solution—repurposing old server hardware to do the job instead.
The build is based around an HP Common Slot (CS) server power supply. They can be readily had for well under $50 if you know where to look. Even better, they can deliver over 50 amps at 12 volts, which happens to be a very useful voltage indeed. All you need to do is some minor mods.
A jumper on a couple of pins will get the power supply running, and with the addition of some terminals for your hook-up leads, you’re ready to go. As a hot-swappable single unit, the power supply is already outfitted with a ventilation fan to keep everything cool. If so desired, you can even make some further mods to bump output voltage a little ways past 13 or 14 volts if you’d like to use them for certain battery charging tasks.
Sure, you’re not getting a variable power supply, but if you need 12 volts and lots of it, this is a great way to go. We’ve featured similar builds before, too, turning ATX PC power supplies into useful benchtop tools.
2026-04-20 07:00:56
We’ll start things off this week with a story that’s developing more than 25 billion kilometers from Earth — on Friday, NASA announced that the command had been sent to shut down Voyager 1’s Low-energy Charged Particles (LECP) instrument. As the power produced by the spacecraft’s aging radioisotope thermoelectric generator (RTG) continues to dwindle, engineers at the Jet Propulsion Laboratory have been systematically turning off various systems to extend the mission for as long as possible. It’s believed that deactivating LECP should buy them another year, during which engineers hope to implement a more ambitious power-saving routine. If this sounds a bit familiar, you’re probably thinking of Voyager 2. The plug was pulled on its LECP instrument back in March of 2025.
The JPL engineers hope that their new plan may allow them to reactivate previously disabled systems on the twin space probes, but even if everything goes according to plan, there’s no fighting the inevitable. At some point, there simply won’t be enough juice in the RTGs to keep the lights on. Although it’s going to be a sad day when we have to bring you that news, surviving a half-century in space is one hell of a run.
Speaking of ending a run, just a week after Amazon announced that pre-2012 Kindles would no longer be supported, the company is letting users know that the Kindle software for PCs will be discontinued in June. In its current form, at least. As Good e-Reader reports, Amazon is developing a new client for users who want to access the Kindle ecosystem from their computers, but it will only run on Windows 11. Since older software could be used to strip DRM from purchased ebooks, it seems likely this is another attempt to lock the platform down.
We’re not fans of arbitrary limits being placed on ebooks and the devices that read them, but on the other hand, there are definitely systems out there that could stand to be tightened up a bit. For example, research out of Quarkslab has shown that the electronic control unit (ECU) from a wrecked vehicle can reveal a surprising amount of information.
After picking up a used ECU, they were able to dump its NAND flash chip and decode the log files it contained. It turns out the car had GPS logs going back to the day it rolled off the assembly line, and the researchers were able to reconstruct every trip it ever made.
By cross-referencing the last recorded coordinates with social media posts, they were even able to find pictures of the crash that took the vehicle out of commission. It’s bad enough that personal information can be scraped off of secondhand hard drives; now we’ve got to worry about what happens to our cars after they get hauled off to the junkyard.
If these are the sort of stories that keep you on two wheels rather than four, you may be interested in the latest innovation from Škoda Auto. In an effort to reduce collisions with pedestrians, they’ve developed a bike bell that penetrates active noise cancellation (ANC) systems. The logic goes like this: if someone is walking around with headphones that feature ANC, they might not hear the bell of an approaching bike. So they teamed up with researchers from the University of Salford to essentially find the weaknesses in existing ANC systems.
As you might have guessed, irregular noises are harder to block out than constant tones. Researchers uncovered a gap between 750 and 780 Hz where sounds could sneak through. The mechanical bell uses both principles to defeat ANC, and in testing, it was shown to provide headphone-wearing pedestrians more time to react to an approaching bicycle.
Finally, we’ll bring this week’s post full circle by starting and ending on a space story: earlier this week, PBS released the hour-long documentary Artemis II: Return to the Moon on YouTube. Watching PBS programming on YouTube might seem a bit odd, but that’s the world we live in these days. At any rate, the video is a fascinating look into what went into the recently concluded Moon mission and has us even more excited for Artemis III and beyond.
See something interesting that you think would be a good fit for our weekly Links column? Drop us a line, we’d love to hear about it.
2026-04-20 04:00:20
Noise cancelling headphones are a great way to insulate yourself from the bustle of the city, but due to their power requirements, continuous use means frequent recharging. [Alessandro Sgarzi] has an elegant and unique solution — powering the noise cancelling electronics by harvesting energy from the ambient noise of the city via a sheet of piezoelectric film.
This impressive feat is achieved using a LTC3588-1 power harvesting IC and a pair of supercapacitors, while an STM32L011K4T6 microcontroller processes the input from a MEMS microphone and feeds a low-power class D amplifier. This circuit consumes an astounding 1.7 nW, a power that a noisy city is amply able to supply. Audio meanwhile comes via a traditional 3.5 mm connector, which we are told is the cool kids’ choice nowadays anyway.
We like this project, and since it’s part of our 2026 Green Powered Challenge, it’s very much in the spirit of the thing. You’ve just got time to get your own entry in, so get a move on!
