A yellow, three wheeled vehicle with a canopy that opens upward over the body. It looks a little like the cockpit of a jet figher.

Restoring A Vintage German EV

When you think of EVs from the 90s, GM’s EV1 may come to mind, but [bleeptrack] found a more obscure CityEL three wheeler to restore.

This Personal Electric Vehicle (PEV) is no spring chicken, but a new set of LiFePO4 batteries should give its 48 V electrical system a new lease on life. [bleeptrack] shows us through the cockpit of this jet fighter-esque EV and its simple control systems, including a forward and reverse selector and the appreciable kilometers on the odometer.

Modernizing touches for this vehicle include a smart shunt to track the vehicle charge level as an improvement over the wildly unreliable original system and a new DC to DC converter after the original unit failed. These changes really cleaned up the electronics compartment from the original rat’s nest under the seat.

The design of this vehicle has us thinking of the Minimal Motoring Manifesto and how EVs could make cars simpler again.

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The MUSE Permanent Magnet Stellarator: Fusion Reactor With Off-The-Shelf Parts

(a) The 12 permanent magnet holder subsegments. (b) The 16 planar, circular toroidal field coils are positioned inside the water-jet cut support structure. (c) The glass vacuum vessel is joined by 3D-printed low-thickness couplers. Glass ports were hot welded to the torus. (Credit: T.M. Qian et al., 2023)
(a) The 12 permanent magnet holder subsegments. (b) The 16 planar, circular toroidal field coils are positioned inside the water-jet cut support structure. (c) The glass vacuum vessel is joined by 3D-printed low-thickness couplers. Glass ports were hot welded to the torus. (Credit: T.M. Qian et al., 2023)

When you think of a fusion reactor like a tokamak or stellarator, you are likely to think of expensive projects requiring expensive electromagnets made out of exotic alloys, whether superconducting or not. The MUSE stellarator is an interesting study in how to take things completely in the opposite direction. Its design and construction is described in a 2023 paper by [T.M. Qian] and colleagues in the Journal of Plasma Physics. The theory is detailed in a 2020 Physical Review Letters paper by [P. Helander] and colleagues. As the head of the Stellarator Theory at the Max Planck Institute, [P. Helander] is well-acquainted with the world’s most advanced stellarator: Wendelstein 7-X.

As noted in the paper by [P. Helander] et al., the use of permanent magnets can substantially simplify the magnetic-field coils of a stellarator, which are then primarily used for the toroidal magnetic flux. This simplification is reflected in the design of MUSE, as it only has a limited number of identical toroidal field coils, with the vacuum vessel surrounded by 3D printed structures that have permanent magnets embedded in them. These magnets follow a pattern that helps to shape the plasma inside the vacuum vessel, while not requiring a power supply or (at least theoretically) cooling.

Naturally, as noted by [P. Helander] et al, a limitation of permanent magnets is their limited field strength, inability to be tuned, and demagnetization at high temperatures. This may limit the number of practical applications of this approach, but researchers at Princeton Plasma Physics Laboratory (PPPL) recently announced in a self-congratulatory article that they will  ‘soon’ commence actual plasma experiments with MUSE. The lack of (cooled) divertors will of course limit the experiments that MUSE can be used for.

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Hackaday Links: April 21, 2024

Do humanoid robots dream of electric retirement? Who knows, but maybe we can ask Boston Dynamics’ Atlas HD, which was officially retired this week. The humanoid robot, notable for its warehouse Parkour and sweet dance moves, never went into production, at least not as far as we know. Atlas always seemed like it was intended to be an R&D platform, to see what was possible for a humanoid robot, and in that way it had a heck of a career. But it’s probably a good thing that fleets of Atlas robots aren’t wandering around shop floors or serving drinks, especially given the number of hydraulic blowouts the robot suffered. That also seems to be one of the lessons Boston Dynamics learned, since Atlas’ younger, nimbler replacement is said to be all-electric. From the thumbnail, the new kid already seems pretty scarred and battered, so here’s hoping we get to see some all-electric robot fails soon.

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Keeping Alive The Future Of Cars, 1980s Style

Here at Hackaday we’re a varied bunch of writers, some of whom have careers away from this organ, and others whose work also appears on the pages of other publications in different fields. One such is our colleague [Lewin Day], and he’s written a cracking piece for The Autopian about the effort to keep an obscure piece of American automotive electronic history alive. We think of big-screen control panels in cars as a new phenomenon, but General Motors was fitting tiny Sony Trinitron CRTs to some models back in the late 1980s. If you own one of these cars the chances are the CRT is inoperable if you’ve not encountered [Jon Morlan] and his work repairing and restoring them.

Lewin’s piece goes into enough technical detail that we won’t simply rehash it here, but it’s interesting to contrast the approach of painstaking repair with that of replacement or emulation. It would be a relatively straightforward project to replace the CRT with a modern LCD displaying the same video, and even to use a modern single board computer to emulate much of a dead system. But we understand completely that to many motor enthusiasts that’s not the point, indeed it’s the very fact it has a frickin’ CRT in the dash that makes the car.We’ll probably never drive a 1989 Oldsmobile Toronado. But we sure want to if it’s got that particular version of the future fitted.

Lewin’s automotive writing is worth watching out for. He once brought us to a motorcycle chariot.

Manual Supports For 3D Printing

[MakerSpace] wanted to 3D print an RFID card holder. On one side is a slot for a card and on the other side has recesses for the RFID antenna. They used these to control access to machines and were milling them out using a CNC machine. Since there were no flat surfaces, he had to turn on supports in the slicer, right? No. He does use supports, but not in the way you might imagine.

Inspired by creating cast iron using sand casting, he decided to first 3D print a reusable “core” using PETG. This core will support future prints that use PLA. When printing the actual item, the printer lays down the first few layers and pauses. This allows you to stick the core in and resume the print. After the print completes, you can remove the core, and the results look great, as you can see in the video below.

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Radio Frequency Burns, Flying A Kite, And You

Most hams can tell you that it’s possible to get a nasty RF burn if you accidentally touch an antenna while it’s transmitting. However, you can also cop a nasty surprise on the receiving end if you’re not careful, as explained in a video from [Grants Pass TV Repair].

It’s hard to see in a still image, but the RF burns from the kite antenna actually generate a little puff of smoke on contact.

An experiment was used to demonstrate this fact involving a kite and a local AM broadcaster. A simple calculation revealed that an antenna 368 feet and 6 inches long would be resonant with the KAJO Radio signal at 1.270 MHz. At half the signal’s wavelength, an antenna that long would capture plenty of energy from the nearby broadcast antenna.

Enter the kite, which served as a skyhook to loft an antenna that long. With the wire in the air picking up a strong signal from the AM radio tower, it was possible to get a noticable RF burn simply by touching the end of the antenna.

The video explains that this is a risky experiment, but not only because of the risk of RF burn itself. It’s also easy to accidentally get a kite tangled in power lines, or to see it struck by lightning, both of which would create far greater injuries than the mild RF burn seen in the video. In any case, even if you know what you’re doing, you have to be careful when you’re going out of your way to do something dangerous in the first place.

AM radio towers aren’t to be messed with; they’ve got big power flowing. Video after the break.

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From Z80 To EZ80: Porting 8-bit Sonic 2 To The TI-84+ CE

An unwritten rule is that if two systems runs even roughly the same CPU, you are obligated to port software between them, or at least give it a fair shake. This led [grubbycoder] down the path of porting Sonic 2 for the Sega Master System (to the eZ80-based Ti 84+ CE. Selecting this particular graphing calculator came down to the raw specs matching up the best, as although the eZ80 in the Ti 84+ runs at 48 MHz, it’s got wait states that cripple its actual performance. Since the calculator also lacks the Video Display Processor (VDP) and a few other bits of hardware, those extra cycles are crucial to compensate.

Sonic 2 on the Ti 84+ CE, courtesy of [grubbycoder]
Sonic 2 on the Ti 84+ CE, courtesy of [grubbycoder]
Getting the disassembled version of the game was easy enough, as the [Sonic Retro] team has already done the heavy lifting there. The only snag there was that this was in WLA-DX assembler format, which is great if you just want to create a ROM for a Z80 system, but for the eZ80 you need a different assembler. Here SPASM-ng came to the rescue, as it targets both Z80 and eZ80-based Ti calculators in particular.

With those ducks aligned, the next task was to address the hardware differences. The calculator has no sound, so those routines had to go, and the color palettes of the Master System had to be mapped to that of the calculator. Since it’s a calculator, there were plenty of buttons for input, but ROM banking – which isn’t a thing on the Ti calculator – and the background and sprite rendering posed some issues. With that sorted, anyone with this calculator can now rejoice at having something better to play on their calculators than Snake in between heavy linear algebra sessions.