A Hybrid Helical Antenna For The Es’hail-2 Geosynchronous Repeater

August 4, 2020 by Dan Maloney 14 Comments

Amateur radio operators like to say that working a contact in space can be done with a simple handheld transceiver and a homemade antenna. And while that’s true, it’s true only for low Earth orbit satellites such as the ISS. If you want to reach a satellite in geosynchronous orbit it’ll take a little more effort, and this dual-feed helical “ice cream cone” antenna could really help.

Until recently, the dream of an amateur radio repeater in geosynchronous orbit remained out of reach, but that changed with the launch of the Qatari satellite Es’hail-2 last year. Since then, hams from Brazil to Thailand have been using the repeater, and UK-based [Tech Minds] has been in the thick of the action. The antenna he presents is a hybrid design, needed because of the 2.4-GHz band uplink and 10-GHz downlink on the satellite, also known as QO-100. Both require a largish dish antenna, with the downlink requiring a low-noise block downconverter (LNB) and feed horn. The uplink side of [Tech Minds]’ antenna is a helical design, with three-and-a-half turns of heavy copper wire and a tuning section of copper strapping that attaches directly to an N-type connector. The helix is just the right size for the feed horn of an LNB for the downlink side, nestled in a hole in the helical antenna’s aluminum reflector disc. There are 3D-printed parts to support everything, plus a cone-shaped radome to keep it all safe from the elements.

It looks like a great design, but sadly, North American and East Asian hams can only dream about building one, since QO-100 is below the horizon for us. We’re jealous, but we’re still glad the repeater is up there. Check out this article for more on how Es’hail-2 got the first geosynchronous ham repeater.

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Unbricking A $2,000 Exercise Bike With A Raspberry Pi Zero And Bluetooth Hacks

August 4, 2020 by Dan Maloney 17 Comments

Really, how did we get the point in this world where an exercise bike can be bricked? Such was the pickle that [ptx2] was in when their $2,000 bike by Flywheel Home Sports was left without the essential feature of participating in virtual rides after Peloton bought the company. The solution? Reverse engineer the bike to get it working with another online cycling simulator.

Sniffing Flywheel Bluetotooth packets with Bluetility

We have to admit we weren’t aware of the array of choices that the virtual biking markets offers. [ptx2] went with Zwift, which like most of these platforms, lets you pilot a smart bike through virtual landscapes along with the avatars of hundreds of other virtual riders. A little Bluetooth snooping with Bluetility let [ptx2] identify the bytes in the Flywheel bike’s packets encoding both the rider’s cadence and the power exerted, which Zwift would need, along with the current resistance setting of the magnetic brake.

Integration into Zwift was a matter of emulating one of the smart bikes already supported by the program. This required some hacking on the Cycling Power Service, a Bluetooth service that Zwift uses to talk to the bike. The final configuration has a Raspberry Pi Zero W between the Flywheel bike and the Zwift app, and has logged about 2,000 miles of daily use. It still needs a motor to control the resistance along the virtual hills and valleys, but that’s a job for another day.

Hats off to [ptx2] for salvaging a $2,000 bike for the price of a Pi and some quality hacking time, and for sticking it to The Man a bit. We have to say that most bike hacks we see around here have to do with making less work for the rider, not more. This project was a refreshing change.

[Featured images: Zwift, Flywheel Sports]

[via r/gadgets]

Hackaday Links: August 2, 2020

August 2, 2020 by Dan Maloney 14 Comments

If you somehow manage to mentally separate yourself from the human tragedy of the COVID-19 pandemic, it really has provided a fascinating glimpse into how our planet operates, and how much impact seven billion people have on it. Latest among these revelations is that the shutdowns had a salubrious effect in at least one unexpected area: solar power. Researchers found that after the Indian government instituted mandatory lockdowns in March, output from solar power installations in Delhi increased by more than eight percent. The cause: the much-diminished smog, which let more sunlight reach solar panels. We’ve seen similar shutdown-related Earth-impact stories, from decreased anthropogenic seismicity to actually being able to see Los Angeles, and find them all delightfully revealing.

Remember Google Glass? It’s hard to forget, what with all the hype leading up to launch and the bitter disappointment of realizing that actually wearing the device wouldn’t go over well in, say, a locker room. That said, the idea of smart glasses had promise, and several startups tried to make a go of combining functionality with less out-there styling that wouldn’t instantly be seen as probable cause for being a creep. One such outfit was North, who made the more-or-less regular looking (if a bit hipsterish) Focals smart glasses. But alas, North was bought out by Google back in June, and as with so many things Google acquires, Focals smart glasses are being turned off. Anyone who bought the $600 specs will reportedly get their money back, but the features of the smart glasses will no longer function. Except, you know, you’ll still be able to look through them.

It looks like someone has finally come up with a pretty good use case for the adorably terrifying robot mini-dogs from Boston Dynamics. Ford Motors has put two of the yellow robots to work in their sprawling Van Dyke Transmission Plant in Michigan. Dubbed Fluffy and Spot (aww), the dogs wander around the plant with a suite of cameras and sensors, digitally mapping the space to prepare for possible future modifications and expansions. The robots can cover a lot of ground during the two hours that their batteries last, and are even said to be able to hitch a ride on the backs of other robots when they’re tuckered out. Scanning projects like these can keep highly trained — and expensive — engineers busy for weeks, so the investment in robots makes sense. And we’re sure there’s totally no way that Ford is using the disarmingly cute robo-pets to keep track of its employees.

We all know that the Linux kernel has some interesting cruft in it, but did you know that it can actually alert you to the fact that your printer is aflame? We didn’t either until Editor-in-Chief Mike Szczys shared this reddit post that details the kernel function lp_check_status and how it assumes the worst if it detects the printer is online but also in “check mode.” The Wikipedia entry on the “lp0 on fire” error message has some interesting history that details how it’s not as implausible as it might seem for a printer, especially one in the early 1970s, to burst into flames under the right conditions. A toner fuser bar running amok on a modern laser printer is one thing, but imagine a printer with a fusing oven running out of control.

And finally, because 2020 is apparently the gift that can’t stop giving, at least in the weirdness department, the US Department of Defense let it slip that the office charged with investigating unidentified aerial phenomena is not quite as disbanded as they once said it was. Reported to have been defunded in 2017, the Advanced Aerospace Threat Identification Program actually appears to live on, as the Unidentified Aerial Phenomena Task Force, operating out of the Office of Naval Intelligence. Their purpose is ostensibly to study things like the Navy videos of high-speed craft out-maneuvering fighter jets, but there are whispers from former members of the task force that “objects of undetermined origin have crashed on earth with materials retrieved for study.” All this could just be a strategic misdirection, of course, but given everything else that has happened this year, we’re prepared to believe just about anything.

Springs And Things Wrap Into A Polyhedron Of Interactive LED Art

August 2, 2020 by Dan Maloney 6 Comments

Any resemblance between The Wobble Sphere and a certain virus making the rounds these days is purely coincidental. Although as yet another project undertaken during the COVID-19 lockdowns, we can see where the inspiration came from.

Wobble Sphere is another work of interactive art from the apparently spring-driven imagination of [Robin Baumgarten], whose Quantum Garden piece graced our pages last year. The earlier, flatter version used a collection of spring door stops — the kind that sound awesome when plucked by a passing foot — each of which is surrounded by a Neopixel ring. The springs act as touch sensors that change the patterns and colors on the LED rings in endlessly fascinating ways.

For Wobble Sphere, [Robin] took the same spring and LED units, broke them into a collection of hexagonal and pentagonal PCBs, and wrapped the whole thing up into a 72-sided polyhedron. There’s some impressive mechanical and electrical engineering involved in the transition from 2D to 3D space, not least of which is solving the problem of how to connect everything while providing pluck-friendly structural support. The former was accomplished with a ton of ribbon cables, while the latter was taken care of with a combination of a 3D-printed skeleton and solder connections between adjacent PCBs. The result is a display that invites touch and rewards it with beautiful patterns of light chasing around the sphere. See it in action in the video after the break.

Lest anyone think springs are the only tool in [Robin]’s box, we mustn’t forget that he once set a knife-wielding Arduino-powered game on an unsuspecting public. Check it out; it’s way more fun than it sounds.

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Art Piece Builds Up Images With Dots On Thread

August 1, 2020 by Dan Maloney 7 Comments

Hackers being as a rule practical people, we sometimes get a little guff when we run a story on an art installation, on the grounds of not being sufficiently hacky. We understand that, but sometimes the way an artist weaves technology into their pieces is just too cool to pass us, as with this thread-printing art piece entitled On Framing Textile Ambiguities.

We’ll leave criticism of the artistic statement that [Nathalie Gebert]’s installation makes to others more qualified, and instead concentrate on its technical aspects. The piece has four frames made mainly from brass rods. Three of the frames have vertical rods that are connected to stepper motors and around which is wrapped a single thread. The thread weaves back and forth over the rods on one frame, forming a flat surface that constantly changes as the rods rotate, before heading off to do the same on the others. The fourth frame has a platen that the thread passes over with a pen positioned right above it. As the thread pauses in its endless loop, the pen clicks down onto it, making a dot of color. The dots then wend their way through the frame, occasionally making patterns that are just shy of recognizable before morphing into something new. The video below shows it better than it can be easily described.

Love it or hate it, you’ve got to admit that it has some interesting potential as a display. And it sort of reminds us of this thread-art polar robot, although this one has the advantage of being far simpler.

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Reverse Engineering The Charge Pump Of An 8086 Microprocessor

July 31, 2020 by Dan Maloney 17 Comments

You’d think that the 8086 microprocessor, a 40-year-old chip with a mere 29,000 transistors on board that kicked off the 16-bit PC revolution, would have no more tales left to tell. But as [Ken Shirriff] discovered, reverse engineering the chip from die photos reveals some hidden depths.

The focus of [Ken]’s exploration of the venerable chip is the charge pump, a circuit that he explains was used to provide a bias voltage across the substrate of the chip. Early chips generally took this -5 volt bias voltage from a pin, which meant designers had to provide a bipolar power supply. To reduce the engineering effort needed to incorporate the 8086 into designs, Intel opted for an on-board charge pump to generate the bias voltage. The circuit consists of a ring oscillator made from a trio of inverters, a pair of transistors, and some diodes to act as check valves. By alternately charging a capacitor and switching its polarity relative to the substrate, the needed -5 volt bias is created.

Given the circuit required, it was pretty easy for [Ken] to locate it on the die. The charge pump takes up a relatively huge amount of die space, which speaks to the engineering decisions Intel made when deciding to include it. [Ken] drills down to a very low level on the circuit, with fascinating details on how the MOSFETs were constructed, and why eight transistors were used instead of two diodes. As usual, his die photos are top quality, as are his explanations of what’s going on down inside the silicon.

If you’re somehow just stumbling upon [Ken]’s body of work, you’re in for a real treat. To get you started, you’ll want to check out how he found pi baked into the silicon of the 8087 coprocessor, or perhaps his die-level exploration of different Game Boy audio chips.

Geocaching On Mars: How Perseverance Will Seal Martian Samples With A Return To Earth In Mind

July 30, 2020 by Dan Maloney 23 Comments

With the roughly 20-day wide launch window for the Mars 2020 mission rapidly approaching, the hype train for the next big mission to the Red Planet is really building up steam. And with good reason — the Mars 2020 mission has been in the works for a better part of a decade, and as we reported earlier this year, the rover it’s delivering to the Martian surface, since dubbed Perseverance, will be among the most complex such devices ever fielded.

“Percy” — come on, that nickname’s a natural — is a mobile laboratory, capable of exploring the Martian surface in search of evidence that life ever found a way there, and to do the groundwork needed if we’re ever to go there ourselves. The nuclear-powered rover bristles with scientific instruments, and assuming it survives the “Seven Minutes of Terror” as well as its fraternal twin Curiosity did in 2012, we should start seeing some amazing results come back.

No prior mission to Mars has been better equipped to answer the essential question: “Are we alone?” But no matter how capable Perseverance is, there’s a limit to how much science can be packed into something that costs millions of dollars a kilogram to get to Mars. And so NASA decided to equip Perseverance with the ability to not only collect geological samples, but to package them up and deposit them on the surface of the planet to await a future mission that will pick them up for a return trip to Earth for further study. It’s bold and forward-thinking, and it’s unlike anything that’s ever been tried before. In a lot of ways, Perseverance’s sample handling system is the rover’s raison d’être, and it’s the subject of this deep dive.

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