Enormous Metal Sculpture Becomes An Antenna

March 23, 2023 by Bryan Cockfield 16 Comments

Those who have worked with high voltage know well enough that anything can be a conductor at high enough voltages. Similarly, amateur radio operators will jump at any chance to turn a random object into an antenna. Flag poles, gutters, and even streams of water can be turned into radiating elements for a transmitter, but the members of this amateur radio club were thinking a little bit bigger when they hooked up their transmitter to this giant sculpture.

For those who haven’t been to the Rochester Institute of Technology (RIT) in upstate New York, the enormous metal behemoth is not a subtle piece of artwork and sits right at the entrance to the university. It’s over 70 feet tall and made out of bronze and steel, a dream for any amateur radio operator. With the university’s permission and some help to ensure everyone’s safety during the operation, the group attached a feedline to the sculpture with a magnet, while the shield wire was attached to a ground rod nearby. A Yaesu FT-991 running on only 5 watts and transmitting in the 20-meter band was able to make contacts throughout much of the eastern United States with this setup.

This project actually started as an in-joke within the radio club, as reported by Reddit user [bbbbbthatsfivebees] who is a member. Eventually the joke became reality, as the sculpture is almost a perfect antenna for certain ham bands. Others in the comments noted that they might have better luck with lower frequency bands such as the 40-meter band or possibly the 60-meter band, due to the height of the structure. And, for those who are still wondering if you really can use a stream of water to transmit radio waves, it is indeed possible.

A clear droplet sits on a blue PCB with gold traces. A syringe with a drop of clear liquid sits above the droplet.

Grow Your Own Brain Electrodes

March 23, 2023 by Navarre Bartz No comments

Bioelectronics has been making great strides in recent years, but interfacing rigid electrical components with biological systems that are anything but can prove tricky. Researchers at the Laboratory for Organic Electronics (LOE) have found a way to bridge the gap with conductive gels. (via Linköping University)

Outside the body, these gels are non-conductive, but when injected into a living animal, the combination of gel and the body’s metabolites creates a conductive electrode that can move with the tissue. This is accompanied by a nifty change in color which makes it easy for researchers to see if the electrode has formed properly.

Applications for the technology include better biological sensors and enhanced capabilities for future brain-controlled interfaces. The study was done on zebrafish and medicinal leeches, so it will be awhile before you can pick up a syringe of this stuff at your local computer store, but it still offers a tantalizing glimpse of the future.

We’ve covered a few different brain electrodes here before including MIT’s 3D printed version and stentrodes.

Ondol: Korean Underfloor Heating

March 23, 2023 by Dave Rowntree 49 Comments

One of the many aspects of the modern world we often take for granted is the very technology that keeps our accommodation at a habitable temperature. Examples of this include centralized heating systems using hot-water circulation, or blown air ducted to multiple rooms from a central furnace. Certainly in Europe, once the Romans shipped out, and before the industrial revolution, we were pretty cold unless someone lit a fire in the room. Every room. But not in Korea. The Ondol heating principles have been used constantly from about 5000 BC to only a few decades ago, keeping your average Korean countryman nice and toasty.

Having said that, the sophistication has improved a bit. Initially, the idea was to simply heat up a bunch of rocks in the fire, and bring them indoors, but Ondol quickly became part of the building itself. As will be seen from the video embedded below, the house sits on top of an elaborate double stack of serpentine channels, that circulate the hot combustion products from the furnace as thoroughly as possible, slowing down the gases and allowing their heat to transfer into the structure of the floor, and then radiate into the space above. It does bear more than a passing resemblance to the Roman hypocaust system, ruined examples of which can be found all over the UK and Europe. The skill demonstrated in the video is considerable, but must surely be an expensive build reserved for the most culturally aware Koreans who wish to live in simpler (and less hectic) locations in their country.

Maybe for the vast majority of us, this kind of thing is not viable, and we’re more likely to benefit from a more centralized approach, perhaps using waste heat from data centers or geothermal activity. (See: Iceland)

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A green PCB with an ISA card slot and various connectors and components. The text "DISAPPOINTMENT LPC to ISA Adapter" is printed in the bottom left of the board.

ISA Over TPM To Your PC

March 23, 2023 by Navarre Bartz 27 Comments

Sometimes you really want to use your legacy SoundBlaster instead of emulating it for classic games. While modern PCs don’t have ISA slots, [TheRasteri] is fixing this shortcoming with his dISAppointment board. (via Adafruit)

ISA was the standard card bus for PCs during the golden age of DOS gaming, and many of these games will still run on modern x86 hardware. Unfortunately, they run into hiccups with regards to sound since they were designed to specifically support ISA-based sound cards. [TheRasteri] found he could access the ISA bus lurking in modern computers through the Low Pin Count (LPC) bus which is exposed on the TPM port in many modern motherboards.

Testing the card with DOOM, he gets music and sound effects with no emulation required. Open Source files and a more detailed video are on the way, so stay tuned if you’re hankering for more ISA goodness on your modern rigs.

We’re no strangers to ISA here. We’ve covered the basics of the ISA bus as well as plugging ISA cards into USB and how you can emulate vintage ISA cards with a Raspberry Pi and FPGA.

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A metal watch is held in a man's fingers. The watchface has a laser etched chess board with miniature chess pieces made of brass enacting a match. The time is told on an etched chess clock to the right hand side of the timepiece and a small window on the rightmost "clock" shows the date.

A Little Chess With Your Timepiece

March 23, 2023 by Navarre Bartz 12 Comments

Some things remain classics, even after centuries, and chess and watches have certainly stood the test of time. [W&M Levsha] decided to combine them both in this “Chess Club” watch containing a miniature chess game frozen in time.

[W&M Levsha] used an off-the-shelf wristwatch for the mechanism and case, but rearranged the parts and built a custom watchface that’s much nicer than the original. The new watchface was cut and etched on a fiber laser after disassembly of the original watch.

The real magic happens when [W&M Levsha] turns those teeny little chess pieces on the lathe. The knight was a two piece affair with the horse head being laser cut out of brass sheet and then soldered onto a turned base. As you can see from the video embedded below, all of the chess pieces inside the watch could fit on the maker’s fingernail! It’s probably a good thing that this tiny set isn’t playable since trying to play on a board that size would be an exercise in patience.

We’ve seen machined chess sets here before at a larger scale, but if you’re more into 3D printing, how about teaching your printer to play?

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PCIe For Hackers: Link Anatomy

March 23, 2023 by Arya Voronova 17 Comments

Last time, we looked over diffpairs, their basics, routing rules and the notorious tolerances of PCIe when it comes to diffpairs. Now, let’s take a look at the exact signals that make PCIe tick, as well as give you an overview of which sockets you can get PCIe on.

I separate PCIe sockets into two categories – desktop sockets, which are the usual 1x, 16x, or perhaps x4 PCIe sockets we see on desktop motherboards — and mobile sockets: mPCIe and M.2. There are also sockets like ExpressCard that are still found on some older laptops, but they have definitely fallen out of relevance. On mobile, M.2 is the way forward when it comes to PCIe – if you’re interested, I’ve written a short series talking about everything M.2 before.

On these sockets, most signals will be optional and some signals will be socket-specific, but there are some signals required in any PCIe device. Of course, the first group of required signals is the PCIe diffpairs themselves.

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Who Needs Gasoline When You’ve Got Sodium?

March 23, 2023 by Dave Rowntree 58 Comments

YouTuber and serial debunker [Thunderf00t] was thinking about the use of sodium to counteract global warming. The theory is that sodium can be used as a fuel when combusted with air, producing a cloud of sodium hydroxide which apparently can have a cooling effect if enough of it is kicking around the upper atmosphere. The idea is to either use sodium directly as a fuel, or as a fuel additive, to increase the aerosol content of vehicle emissions and maybe reduce their impact a little.

One slight complication to using sodium as a fuel is that it’s solid at room temperature, so it would need to be either delivered as pellets or in liquid form. That’s not a major hurdle as the melting point is a smidge below 100 degrees Celsius and well within the operating region of an internal combustion engine, but you can imagine the impact of metal solidifying in your fuel system. Luckily, just like with solder eutectic mixes, sodium-potassium alloy happens to remain in liquid form at handleable temperatures and only has a slight tendency to spontaneously ignite. So that’s good.

Initial experiments using ultrasonic evaporators proved somewhat unsuccessful due to the alloy’s electrical conductivity and tendency to set everything on fire. The next attempt was using a standard automotive fuel injector from the petrol version of the Ford Fiesta. Using a suitable container, a three-way valve to allow the introduction of fuels, and an inert argon feed (preventing spontaneous combustion in the air), delivering the liquid metal fuel into the fuel injector seems straightforward enough.

[Thunderf00t] started with ethanol, then worked up to pentane before finally attempting to use the feisty sodium-potassium, once the bugs had been shaken out of the high-speed video setup. [Thunderf00t] does stress the importance of materials selection when handling this potential liquid metal fuel, since it apparently just bursts into flames in a violent manner on contact with incompatible materials. Heck, this stuff even reacts with PTFE, which is generally considered a very resistant material. We’re totally convinced we’d not like to see this stuff being pumped from a roadside gas station, at all, but it sure is a fun concept to think about.

Sodium-Potassium alloy doesn’t feature on these pages too often, but here’s a little fountain of the stuff, just because why not?

Continue reading “Who Needs Gasoline When You’ve Got Sodium?” →