The Trials And Tribulations Of E-Bike Drivetrain Design

[Tom Stanton] is well-regarded in the maker community, and has put much effort in over the years on a variety of electric vehicle builds. In the process of upgrading his e-bike last year, he ran into some issues with the main drive pulley. Rather than rely on guesswork, he threw engineering at the problem.

Static weight tests were carried out in combination with FEA to determine the root cause of the problem.

The problem concerned the mounting bolts on the pulley’s hub, which would pull out under high torque. [Tom’s] initial finite element simulations had suggested the design was sound, but reality was proving otherwise. After further analysis and testing, [Tom] determined that his analysis hadn’t properly simulated the bolt pull-out condition. With this corrected in the software, it was readily apparent that there simply wasn’t enough material around the bolt holes to hold the torque load.

With the simulation now more closely agreeing with reality, [Tom] was able to correct the design. New parts were created with a strengthened mounting section, and the pulley was successfully able to deal with the loads in service.

It’s a great example of using engineering simulation tools to solve a problem quickly, rather than simply guessing and hoping things will hold up. We’ve seen [Tom]’s work before, too — like this fun backyard trebuchet build. Video after the break.

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The Satellite Phone You Already Own: From Orbit, UbiquitiLink Will Look Like A Cell Tower

For anyone that’s ever been broken down along a remote stretch of highway and desperately searched for a cell signal, knowing that a constellation of communications satellites is zipping by overhead is cold comfort indeed. One needs specialized gear to tap into the satphone network, few of us can justify the expense of satellite phone service, and fewer still care to carry around a brick with a chunky antenna on it as our main phone.

But what if a regular phone could somehow leverage those satellites to make a call or send a text from a dead zone? As it turns out, it just might be possible to do exactly that, and a Virginia-based startup called UbiquitiLink is in the process of filling in all the gaps in cell phone coverage by orbiting a constellation of satellites that will act as cell towers of last resort. And the best part is that it’ll work with a regular cell phone — no brick needed.

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STEP Up Your Jetson Nano Game With These Printable Accessories

Found yourself with a shiny new NVIDIA Jetson Nano but tired of having it slide around your desk whenever cables get yanked? You need a stand! If only there was a convenient repository of options that anyone could print out to attach this hefty single-board computer to nearly anything. But wait, there is! [Madeline Gannon]’s accurately named jetson-nano-accessories repository supports a wider range of mounting options that you might expect, with modular interconnect-ability to boot!

A device like the Jetson Nano is a pretty incredible little System On Module (SOM), more so when you consider that it can be powered by a boring USB battery. Mounted to NVIDIA’s default carrier board the entire assembly is quite a bit bigger than something like a Raspberry Pi. With a huge amount of computing power and an obvious proclivity for real-time computer vision, the Nano is a device that wants to go out into the world! Enter these accessories.

At their core is an easily printable slot-and-tab modular interlock system which facilitates a wide range of attachments. Some bolt the carrier board to a backplate (like the gardening spike). Others incorporate clips to hold everything together and hang onto a battery and bicycle. And yes, there are boring mounts for desks, tripods, and more. Have we mentioned we love good documentation? Click into any of the mount types to find more detailed descriptions, assembly directions, and even dimensioned drawings. This is a seriously professional collection of useful kit.

Air Hockey Table Is A Breeze To Build

Many of us have considered buying an air hockey table, but are put off by the price. And even if the money is there, those things take up a lot of space. How often are you really going to use it?

This DIY air hockey table is the answer. It’s big enough to be fun, but small and light enough to easily stow away in the off-season. At ~$50, it’s a cheap build, provided you have a vacuum cleaner that can switch to blower mode. The strikers, goals, corner guards, and scoreboard enclosure are all 3D-printed, while the pucks and playfield are laser-cut acrylic. [Technovation] glued acrylic feet to the strikers to help them last longer.

The scoreboard is an Arduino Uno plus an LCD that changes color to match the current winner. Scoring must be entered manually with button presses, but we think it would be fairly easy to detect a puck in the goal with a force or weight sensor or something. For now, the RGB LEDs around the edge are controlled separately with a remote. The ultimate goal is to make the Arduino do it. Shoot past the break and cross-check it out.

Already have a table? Had it so long, no one will play you anymore? Build yourself a robotic opponent.

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Vintage Console Becomes The Calculator It Appears To Be

What’s sitting on [Bob Alexander]’s desk in the video below did not start out life as the desktop calculator it appears to be. Turning it into a standalone calculator with features the original designers couldn’t imagine turned out to be an interesting project, and a trip down the retrocomputing rabbit hole.

A little explanation is in order. Sure, with its Nixie display, calculator keypad, and chunky mid-century design, the Wang 360 desktop console looks like a retro calculator. But it’s actually only a dumb terminal for a much, MUCH bigger box, called the Electronic Package, that would fit under a desk. The foot-warming part that was once connected to [Bob]’s console by a thick cable that had been unceremoniously lopped off by a previous owner. [Bob] decided to remedy the situation with modern electronics. The console turned out to have enough room for a custom PCB carrying a PIC32, some level-shifting components, power supply modules that include the high-voltage supply for the Nixies, and a GPS module because Nixies and clocks just go together. The interesting bit is the programming; [Bob] chose to emulate the original Wang methods of doing math, which include multiplication by logarithmic addition. Doing so replicates the original look and feel of the calculator down to the rapid progression of numbers across the Nixies as the logarithms are calculated using the display registers.

We normally frown on vintage gear being given modern guts, but in this case [Bob] hit just the right balance of new and old, And given that the Electronic Packages these consoles were connected to go for $1500 or more on eBay, it was a better choice than letting the console go to scrap. A similarly respectful approach was taken with this TRS80 Model 100 revival.

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NES Gets A Slick Acrylic Casemod

Those alive during the 1990s will remember the clear or “crystal” versions of various home consoles. Made with the usual injection molding processes, they usually came out somewhere closer to a smoky translucency and didn’t reveal much of the insides. [BitHead1000] likes to do things right though, and has busted out an awesome acrylic case mod for his NES.

The build starts with the disassembly of the original console, naturally, and the RF shielding is discarded in order to provide an unobstructed view of the internals. The acrylic case is then built up piece by piece, using the original case as a template. Flame polishing is used to treat the edges, and everything is stuck together using what appears to be acrylic cement. For a nice finishing touch, the cartridge door gets a frosted Nintendo logo, thanks to some careful work in the sandblasting booth.

The final product looks stunning, and the transparent case lends itself excellently to edge-lighting thanks to a few LEDs. We’ve seen [BitHead1000’s] work before, with the stunning flamethrowing N64 build. Video after the break.

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Hackaday Links: August 25, 2019

Doesn’t the Z-axis on 3D-printers seem a little – underused? I mean, all it does is creep up a fraction of a millimeter as the printer works through each slice. It would be nice if it could work with the other two axes and actually do something interesting. Which is exactly what’s happening in the nonplanar 3D-printing methods being explored at the University of Hamburg. Printing proceeds normally up until the end, when some modifications to Slic3r allow smooth toolpaths to fill in the stairsteps and produce a smooth(er) finish. It obviously won’t work for all prints or printers, but it’s nice to see the Z-axis finally pulling its weight.

If you want to know how something breaks, best to talk to someone who looks inside broken stuff for a living. [Roger Cicala] from LensRentals.com spends a lot of time doing just that, and he has come to some interesting conclusions about how electronics gear breaks. For his money, the prime culprit in camera and lens breakdowns is side-mounted buttons and jacks. The reason why is obvious once you think about it: components mounted perpendicular to the force needed to operate them are subject to a torque. That’s a problem when the only thing holding the component to the board is a few SMD solder pads. He covers some other interesting failure modes, too, and the whole article is worth a read to learn how not to design a robust product.

In the seemingly neverending quest to build the world’s worst Bitcoin mining rig, behold the 8BitCoin. It uses the 6502 processor in an Apple ][ to perform the necessary hashes, and it took a bit of doing to port the 32-bit SHA256 routines to an 8-bit platform. But therein lies the hack. But what about performance? Something something heat death of the universe…

Contributing Editor [Tom Nardi] dropped a tip about a new online magazine for people like us. Dubbed Paged Out!, the online quarterly ‘zine is a collection of contributed stories from hackers, programmers, retrocomputing buffs, and pretty much anyone with something to say. Each article is one page and is formatted however the author wants to, which leads to some interesting layouts. You can check out the current issue here; they’re still looking for a bunch of articles for the next issue, so maybe consider writing up something for them – after you put it on Hackaday.io, of course.

Tipline stalwart [Qes] let us know about an interesting development in semiconductor manufacturing. Rather than concentrating on making transistors smaller, a team at Tufts University is making transistors from threads. Not threads of silicon, or quantum threads, or threads as a metaphor for something small and high-tech. Actual threads, like for sewing. Of course, there’s plenty more involved, like carbon nanotubes — hey, it was either that or graphene, right? — gold wires, and something called an ionogel that holds the whole thing together in a blob of electrolyte. The idea is to remove all rigid components and make truly flexible circuits. The possibilities for wearable sensors could be endless.

And finally, here’s a neat design for an ergonomic utility knife. It’s from our friend [Eric Strebel], an industrial designer who has been teaching us all a lot about his field through his YouTube channel. This knife is a minimalist affair, designed for those times when you need more than an X-Acto but a full utility knife is prohibitively bulky. [Eric’s] design is a simple 3D-printed clamshell that holds a standard utility knife blade firmly while providing good grip thanks to thoughtfully positioned finger depressions. We always get a kick out of watching [Eric] design little widgets like these; there’s a lot to learn from watching his design process.

Thanks to [JRD] and [mgsouth] for tips.