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Hackaday Links: May 23, 2021

The epicenter of the Chinese electronics scene drew a lot of attention this week as a 70-story skyscraper started wobbling in exactly the way skyscrapers shouldn’t. The 1,000-ft (305-m) SEG Plaza tower in Shenzhen began its unexpected movements on Tuesday morning, causing a bit of a panic as people ran for their lives. With no earthquakes or severe weather events in the area, there’s no clear cause for the shaking, which was clearly visible from the outside of the building in some of the videos shot by brave souls on the sidewalks below. The preliminary investigation declared the building safe and blamed the shaking on a combination of wind, vibration from a subway line under the building, and a rapid change in outside temperature, all of which we’d suspect would have occurred at some point in the 21-year history of the building. Others are speculating that a Kármán vortex Street, an aerodynamic phenomenon that has been known to catastrophically impact structures before, could be to blame; this seems a bit more likely to us. Regardless, since the first ten floors of SEG Plaza are home to one of the larger electronics markets in Shenzhen, we hope this is resolved quickly and that all our friends there remain safe.

In other architectural news, perched atop Building 54 at the Massachusetts Institute of Technology campus in Cambridge for the last 55 years has been a large, fiberglass geodesic sphere, known simply as The Radome. It’s visible from all over campus, and beyond; we used to work in Kendall Square, and the golf-ball-like structure was an important landmark for navigating the complex streets of Cambridge. The Radome was originally used for experiments with weather radar, but fell out of use as the technology it helped invent moved on. That led to plans to remove the iconic structure, which consequently kicked off a “Save the Radome” campaign. The effort is being led by the students and faculty members of the MIT Radio Society, who have put the radome to good use over the years — it currently houses an amateur radio repeater, and the Radio Society uses the dish within it to conduct Earth-Moon-Earth (EME) microwave communications experiments. The students are serious — they applied for and received a $1.6-million grant from Amateur Radio Digital Communications (ARDC) to finance their efforts. The funds will be used to renovate the deteriorating structure.

Well, this looks like fun: Python on a graphing calculator. Texas Instruments has announced that their TI-84 Plus CE Python graphing calculator uses a modified version of CircuitPython. They’ve included seven modules, mostly related to math and time, but also a suite of TI-specific modules that interact with the calculator hardware. The Python version of the calculator doesn’t seem to be for sale in the US yet, although the UK site does have a few “where to buy” entries listed. It’ll be interesting to see the hacks that come from this when these are readily available.

Did you know that PCBWay, the prolific producer of cheap PCBs, also offers 3D-printing services too? We admit that we did not know that, and were therefore doubly surprised to learn that they also offer SLA resin printing. But what’s really surprising is the quality of their clear resin prints, at least the ones shown on this Twitter thread. As one commenter noted, these look more like machined acrylic than resin prints. Digging deeper into PCBWay’s offerings, which not only includes all kinds of 3D printing but CNC machining, sheet metal fabrication, and even injection molding services, it’s becoming harder and harder to justify keeping those capabilities in-house, even for the home gamer. Although with what we’ve learned about supply chain fragility over the last year, we don’t want to give up the ability to make parts locally just yet.

And finally, how well-calibrated are your fingers? If they’re just right, perhaps you can put them to use for quick and dirty RF power measurements. And this is really quick and really dirty, as well as potentially really painful. It comes by way of amateur radio operator VK3YE, who simply uses a resistive dummy load connected to a transmitter and his fingers to monitor the heat generated while keying up the radio. He times how long it takes to not be able to tolerate the pain anymore, plots that against the power used, and comes up with a rough calibration curve that lets him measure the output of an unknown signal. It’s brilliantly janky, but given some of the burns we’ve suffered accidentally while pursuing this hobby, we’d just as soon find another way to measure RF power.

A High Power Wood Rocket In 5 Days

Getting started with model rocketry is relatively cheap and easy, but as you move up in high power rocketry, there are a few hoops to jump through. To be able to buy rocket motors larger than H (160 N·s / 36 lbf·s impulse) in the US, you need to get certified by the National Association of Rocketry. The main requirement of this certification involves building, flying, and recovering a rocket with the specific motor class required for the certification level. [Xyla Foxlin] had committed to doing her Level 2 certification with a couple of friends, thanks to the old procrastination monster, was forced to build a rocket with only 5 days remaining to launch data.

For Level 2 certification, the rocket needs to fly with a J motor, which is capable of producing more than 640 N·s of impulse. Fortunately [Xyla] had already designed the rocket in OpenRocket, and ordered the motor and major body, nosecone, and parachute components. The body was built around 2 sections of 3″ cardboard tubes, which are covered in a few layers of fiberglass. The stabilizing fins were laser cut from cheap plywood and were epoxied to the inner tube which holds the motor and passes through the sides of the outer tube. The fins are also fibreglassed to increased strength. For a unique touch, she covered the rocket with a real wood veneer, with the rocket’s name, [Fifi], inlaid with darker wood. The recovery system is a basic parachute, connected to the rocket body with Kevlar rope.

[Xyla] finished her rocket just in time for the trek out to the rocket range. She successfully did the certification flight and recovered [Fifi] in reusable condition, which is a requirement. There was nothing groundbreaking about [Fifi], but then again, reliability the main requirement. You don’t want to do a certification with a fancy experimental rocket that could easily fail. Continue reading “A High Power Wood Rocket In 5 Days”

RC Car Gets Fan-Assisted Downforce To Slay Tesla’s 0-60 Times

Tesla have claimed that their upcoming new Roadster will post a sub-2 second 0-60mph time. While it’s backed up by little more than a shiny website at this stage, [Engineering After Hours] took the number as a target to beat with his RC fan car build. (Video, embedded below.)

We’ve seen an earlier prototype of this build before, with the first version generating enough downforce to successfully drive upside down. The new build has several modifications to maximise its lateral acceleration capabilities. The new build drives all four wheels, which are fitted with sticky tyres coated in traction compound for maximum grip. The main drive motor, along with the fan and skirt assemblies, are all mounted in the center of the car now to properly balance the aero loads across the axles and provide a stable weight distribution for fast launches.

The results are impressive, with the car posting a 0-60mph time of just 1.825 seconds. There’s likely still time left on the table, too, once the car can be tuned to launch harder off the line. We’d love to see a racing series of fan-equipped RC cars hit the track, too, given the amount of grip available with such hardware.

Continue reading “RC Car Gets Fan-Assisted Downforce To Slay Tesla’s 0-60 Times”

Smart Guitar Will Practically Play Itself

Playing the guitar is pretty difficult to do, physically speaking. It requires a lot of force with the fretting hand to produce clear notes, and that means pressing a thin piece of metal against a block of wood until the nerve endings in your fingertips die off and you grow calluses that yearn to be toughened even further. Even if you do get to this point of being broken in, it takes dexterity in both hands to actually make music. Honestly, the guitar is kind of an unwelcoming instrument, even if you don’t have any physical disabilities.

A Russian startup company called Noli Music wants to change all of that. They’re building a guitar that’s playable for everyone, regardless of physical or musical ability. Noli Music was founded by [Denis Goncharov] who has a form of muscular dystrophy. [Denis] has always wanted to rock out to his favorite songs, but struggles to play a standard guitar.

If you can touch the fretboard, it seems, you can whale away on this axe without trouble. It’s made to be easier to play all around. The strings aren’t fully tensioned, so they’re easy to pluck — the site says they only take 1.7oz of force to actuate.

Right now, the guitar is in the prototype stage. But when it’s ready to rock, it will do so a couple of ways. One uses embedded sensors in the fretboard detect finger positions and sound the appropriate note whether you pluck it or simply fret it. In another mode, the finger positions light up to help you learn new songs. The guitar will have a touchscreen interface, and Noli are planning on building a companion app to provide interactive lessons.

We have to wonder just how exactly this will be able to mimic the physics of guitar playing, especially since it’s designed with all players in mind. How satisfied will seasoned players be with this instrument? Can it do pull-offs and hammer-ons? What about slides? Do the sensors respond to bends? And most importantly, will the built-in speaker be loud enough to drown out the string vibrations? It seems to do just fine on that front, as you can see in the video below.

If the built-in speaker didn’t drown out the strings, it could make for some interesting sounds that stray outside the western chromatic scale, much like this LEGO microtonal guitar.

Continue reading “Smart Guitar Will Practically Play Itself”

Design An Electronic Catan Board In A Day

One of the things that makers sometimes skip over is the design of the project that they’re creating. Some of us don’t do any design at all, we just pants it. The design part of making something can take quite a while – there is sketching to do, as well as 3d-modelling and PCB creation. [Sam March] wanted to try and create something interesting where he did the design in a single day. The result is, or will be, a 3D printed, electronic, Settlers of Catan game board.

Continue reading “Design An Electronic Catan Board In A Day”

Modifying Lights For DIY Ambiance

The ESP32 and ESP8266 spread like wildfire a few years ago due to their small form factor, low price, and wireless capability. They didn’t just take over the DIY scene, though. Plenty of mass market products began to incorporate these tiny chips as well, which means that there are some interesting pre-made devices around that are ripe for modification. In this case, using an off-brand smart light bulb as a base for an semi-proprietary lighting setup.

The lighting in this build is a generic RGB light bulb with the ability to control its color over Wi-Fi. Since it has an ESP8266 chip in it, it can be made to work with Philips Hue lights with some minor modifications, allowing a much wider range of control than otherwise available. For this one, [Vadim] needed to pry open the bulb case to access the chip, then solder wires to it for reprogramming. It needed power during this step which meant plugging the resulting mess of wires back into a lamp socket, but after this step the new programming allows the bulb to be reprogrammed remotely.

After that step is complete, though, the generic bulb is ready for its inclusion into a Hue lighting system. In this case, [Vadim] is using diyHue, a Hue emulator that allows control of the bulbs without needing to use any cloud services, running on a BeagleBone. It’s a fairly comprehensive way of adding many different types and brands of bulbs to one system, and avoids any subscription models or the use of a cloud service, which is always something we can get behind.

Continue reading “Modifying Lights For DIY Ambiance”

Adding Remote Controls To A Blackmagic Studio Camera Without Breaking The Bank

What to do when one ends up in the possession of a 4K studio camera, but without the requisite hardware and software to remotely control it? When [Glen Akins] ended up in this situation, he took the reasonable option here and developed his own knob-based remote control to adjust exposure and focus on the Blackmagic Designs Micro Studio Camera 4K. Without a remote control option, the only adjustment options are via fiddly small buttons on the camera itself, which wouldn’t have been a fun experience during the webcam usage that this camera would be used for.

This camera is normally controlled via the control channel on the SDI input which also handles the video output from the camera. For larger installations the proprietary ATEM software is commonly used, and there’s a $99 Arduino expansion board as well that’s apparently rarely stocked. With SDI not an option, the second option was LANC, which runs into pretty much the same issue with proprietary protocols and very expensive hardware.

Behind door number three is the more curious control option of the Futaba S.BUS protocol. Originally created for remotely controlling radio-controlled aircraft and similar remotely controlled systems, the thought here appears to be that this studio camera can also be used with systems that already have an S.BUS receiver, such as large drones.

With this S.BUS protocol having been reverse-engineered for a while now, it was a fairly straightforward procedure from there to create an MCU-based board with a lot of encoder knobs on it that map to a specific adjustment on the camera. The result of [Glen]’s labor can be found on GitHub.

Main image: The finished knob-box with the Blackmagic Designs camera. (Credit: Glen Akins)