Implantable Battery Charges Itself

April 25, 2024 by 2 Comments

Battery technology is the major limiting factor for the large-scale adoption of electric vehicles and grid-level energy storage. Marginal improvements have been made for lithium cells in the past decade but the technology has arguably been fairly stagnant, at least on massive industrial scales. At smaller levels there have been some more outside-of-the-box developments for things like embedded systems and, at least in the case of this battery that can recharge itself, implantable batteries for medical devices.

The tiny battery uses sodium and gold for the anode and cathode, and takes oxygen from the body to complete the chemical reaction. With a virtually unlimited supply of oxygen available to it, the battery essentially never needs to be replaced or recharged. In lab tests, it took a bit of time for the implant site to heal before there was a reliable oxygen supply, though, but once healing was complete the battery’s performance leveled off.

Currently the tiny batteries have only been tested in rats as a proof-of-concept to demonstrate the chemistry and electricity generation capabilities, but there didn’t appear to be any adverse consequences. Technology like this could be a big improvement for implanted devices like pacemakers if it can scale up, and could even help fight diseases and improve healing times. For some more background on implantable devices, [Dan Maloney] catches us up on the difficulties of building and powering replacement hearts for humans.

Sticky Situation Leads To Legit LEGO Hack

April 24, 2024 by No comments

[samsuksiri] frequently uses a laptop and has an external drive to store projects. The drive flops around on the end of its tether and gets in the way, so they repurposed their old iPod pouch and attached it to the laptop lid with double-sided tape. You can guess how that went — the weight of the drive caused the pocket to sag and eventually detach over time.

Then [samsuksiri] remembered that they had LEGO DOTS patch stashed somewhere. It’s an 8×8 plate with adhesive on the back so you can build almost anywhere. Then the problem was this: how to attach LEGO to the drive itself? You’d think this is where the hot glue comes in, but that didn’t work because the drive is too slippery.

Nothing worked, really — not until [samsuksiri] flipped the drive over to work with the dimpled side that has un-coated plastic. Finally, the answer turned out to be mounting tape. Now, [samsuksiri] can attach the drive in any orientation, or even attach a second drive. Be sure to check it out after the break.

Looking for slightly more astounding LEGO creations? Check out this hydroelectric dam.

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The Performance Impact Of C++’s `final` Keyword For Optimization

April 24, 2024 by 6 Comments

In the world of software development the term ‘optimization’ is generally reason for experienced developers to start feeling decidedly nervous, especially when a feature is marked as an ‘easy and free optimization’. The final keyword introduced in C++11 is one of such features. It promises a way to speed up object-oriented code by omitting the vtable call indirection by marking a class or member function as – unsurprisingly – final, meaning that it cannot be inherited from or overridden. Inspired by this promise, [Benjamin Summerton] figured that he’d run a range of benchmarks to see what performance uplift he’d get on his ray tracing project.

To be as thorough as possible, the tests were run on three different systems, including 64-bit Intel and AMD systems, as well as on Apple Silicon (M1). For the compilers various versions of GCC (12.x, 13.x), as well as Clang  (15, 17) and MSVC (17) were employed, with rather interesting results for final versus no final tests. Clang was probably the biggest surprise, as with the keyword added, performance with Clang-generated code absolutely tanked. MSVC was a mixed bag, as were the GCC versions other than GCC 13.2 on AMD Ryzen, which saw a bump of a few percent faster.

Ultimately, it seems that there’s no free lunch as usual, and adding final to your code falls distinctly under ‘only use it if you know what you’re doing’. As things stand, the resulting behavior seems wildly inconsistent.

Downloading Satellite Imagery With A Wi-Fi Antenna

April 24, 2024 by 3 Comments

Over the past century or so we’ve come up with some clever ways of manipulating photons to do all kinds of interesting things. From lighting to televisions and computer screens to communication, including radio and fiber-optics, there’s a lot that can be done with these wave-particles and a lot of overlap in their uses as well. That’s why you can take something like a fairly standard Wi-Fi antenna meant for fairly short-range communication and use it for some other interesting tasks like downloading satellite data.

Weather satellites specifically use about the same frequency range as Wi-Fi, but need a bit of help to span the enormous distance. Normally Wi-Fi only has a range in the tens of meters, but attaching a parabolic dish to an antenna can increase the range by several orders of magnitude. The dish [dereksgc] found is meant for long-range Wi-Fi networking but got these parabolic reflectors specifically to track satellites and download the information they send back to earth. Weather satellites are generally the target here, and although the photons here are slightly less energy at 1.7 GHz, this is close enough to the 2.4 GHz antenna design for Wi-Fi to be perfectly workable and presumably will work even better in the S-band at around 2.2 GHz.

For this to work, [dereksgc] isn’t even using a dedicated tracking system to aim the dish at the satellites automatically; just holding it by hand is enough to get a readable signal from the satellite, especially if the satellite is in a geostationary orbit. You’ll likely have better results with something a little more precise and automated, but for a quick and easy solution a surprisingly small amount of gear is actually needed for satellite communication.
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More Mirrors (and A Little Audio) Mean More Laser Power

April 24, 2024 by 6 Comments

Lasers are pretty much magic — it’s all done with mirrors. Not every laser, of course, but in the 1980s, the most common lasers in commercial applications were probably the helium-neon laser, which used a couple of mirrors on the end of a chamber filled with gas and a high-voltage discharge to produce a wonderful red-orange beam.

The trouble is, most of the optical power gets left in the tube, with only about 1% breaking free. Luckily, there are ways around this, as [Les Wright] demonstrates with this external passive cavity laser. The guts of the demo below come from [Les]’ earlier teardown of an 80s-era laser particle counter, a well-made instrument powered by a He-Ne laser that was still in fine fettle if a bit anemic in terms of optical power.

[Les] dives into the physics of the problem as well as the original patents from the particle counter manufacturer, which describe a “stabilized external passive cavity.” That’s a pretty fancy name for something remarkably simple: a third mirror mounted to a loudspeaker and placed in the output path of the He-Ne laser. When the speaker is driven by an audio frequency signal, the mirror moves in and out along the axis of the beam, creating a Doppler shift in the beam reflected back into the He-Ne laser and preventing it from interfering with the lasing in the active cavity. This forms a passive cavity that greatly increases the energy density of the beam compared to the bare He-Ne’s output.

The effect of the passive cavity is plain to see in the video. With the oscillator on, the beam in the passive cavity visibly brightens, and can be easily undone with just the slightest change to the optical path. We’d never have guessed something so simple could make such a difference, but there it is.

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DIY DNA Lamp

DIY Electronics Plus Woodworking Equal Custom Lamp

April 24, 2024 by 3 Comments

There is something about wooden crafts that when combined with electronics, have a mesmerizing effect on the visual senses. The Gesture Controlled DNA Wooden Desk Lamp by [Timber Rough] is a bit of both with a nice desk piece that’s well documented for anyone who wants to build their own.

Construction starts with a laser cutter being employed to add kerfs, such that the final strips can be bent along a frame tube to form the outer backbone of the DNA helix structure. Add to the mix some tung oil, carnauba wax, and some glue — along with skill and patience — and you get the distinct shape of sugar-phosphate backbone.

The electronics include an ESP8266 with the PAJ7620 gesture sensor that controls two WS2812B RGB LED Strips. The sensor in question is very capable, and comes with the ability to recognize nine human hand gestures along with proximity which makes it apt for this application. The sensor is mounted atop the structure with the LEDs twisting down the frame to the base where the ESP8266 is tucked away. Tiny glass bottles are painted with acrylic spray varnish and then glued to the LEDs to form the base pairs of the double helix. We thought that the varnish spray was a clever idea to make light diffusers that are quick and cheap for most DIYers.

We previously covered how this particular gesture sensor can be used to control much more than a lamp if you seek more ideas in that realm.

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Supercon 2023: Alex Lynd Explores MCUs In Infosec

April 24, 2024 by 9 Comments

The average Hackaday reader hardly needs to be reminded of the incredible potential of the modern microcontroller. While the Arduino was certainly transformative when it hit the scene, those early 8-bit MCUs were nothing compared to what’s on the market now. Multiple cores with clock speeds measured in the hundreds of megahertz, several MB of flash storage, and of course integrated WiFi capability mean today’s chips are much closer to being fully-fledged computers than their predecessors.

It’s not hard to see the impact this has had on the electronics hobby. In the early 2000s, getting your hardware project connected to the Internet was a major accomplishment that probably involved bringing some hacked home router along for the ride. But today, most would consider something like an Internet-connected remote environmental monitor to be a good starter project. Just plug in a couple I2C sensors, write a few lines of Python, and you’ve got live data pouring into a web interface that you can view on your mobile device — all for just a few bucks worth of hardware.

But just because we’re keenly aware of the benefits and capabilities of microcontrollers like the ESP32 or the Pi Pico, doesn’t mean they’ve made the same impact in other tech circles. In his talk Wireless Hacking on a $5 Budget, Alex Lynd goes over some examples of how he’s personally put these devices to work as part of his information security (infosec) research.

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