How To Make An Electric Scooter Chain Sprocket With Nothing But Hand Tools

Sometimes, mechanical parts can be supremely expensive, or totally unavailable. In those cases, there’s just one option — make it yourself. It was this very situation in which I found myself. My electric scooter had been ever so slightly bested by a faster competitor, and I needed redemption. A gearing change would do the trick, but alas, the chain sprocket I needed simply did not exist from the usual online classifieds.

Thus, I grabbed the only tools I had, busied myself with my task. This is a build that should be replicable by anyone comfortable using a printer, power drill, and rotary tool. Let’s get to work!

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Open Hardware Month Hack Chat

Join us on Wednesday, October 23 at noon Pacific for the Open Hardware Month Hack Chat with Michael Weinberg!

It seems like everything and everyone has a special day set aside on the calendar. You know the drill – a headline declaring it National Grilled Cheese Day (sorry, you missed it – April 12) or National Bundt Pan Day (not even kidding, November 15). It seems only fair with all these silly recognition days floating around that we in the hacking community should have a day of our own, too, or even a whole month. That’s why the Open Source Hardware Association declared the entire month of October to be Open Hardware Month.

Open hardware is all about accessible, collaborative processes that let everyone see and understand the hardware they’re using. The technological underpinnings of our lives are increasingly hidden from us, locked away as corporate secrets. Open hardware tries to turn that on its head and open up devices to everyone, giving them the freedom to not only use their devices but to truly understand what’s happening in them, and perhaps repair, extend, and even modify them to do something new and useful. Celebrating that and getting the message out to the general public is certainly something worth doing.

Michael Weinberg is a board member at OSHWA, and he’ll be joining the Hack Chat on October 23 (National Boston Cream Pie Day) to discuss Open Hardware Month and open-source hardware in general. We’ll learn about some of the events planned for Open Hardware Month, how open hardware is perceived beyond the hacker community, and what’s on tap for the 10th anniversary Open Hardware Summit in 2020.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 23 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Hackaday Links: October 20, 2019

It’s Nobel season again, with announcements of the prizes in literature, economics, medicine, physics, and chemistry going to worthies the world over. The wording of the Nobel citations are usually a vast oversimplification of decades of research and end up being a scientific word salad. But this year’s chemistry Nobel citation couldn’t be simpler: “For the development of lithium-ion batteries”. John Goodenough, Stanley Whittingham, and Akira Yoshino share the prize for separate work stretching back to the oil embargo of the early 1970s, when Goodenough invented the first lithium cathode. Wittingham made the major discovery in 1980 that adding cobalt improved the lithium cathode immensely, and Yoshino turned both discoveries into the world’s first practical lithium-ion battery in 1985. Normally, Nobel-worthy achievements are somewhat esoteric and cover a broad area of discovery that few ordinary people can relate to, but this is one that most of us literally carry around every day.

What’s going on with Lulzbot? Nothing good, if the reports of mass layoffs and employee lawsuits are to be believed. Aleph Objects, the Colorado company that manufactures the Lulzbot 3D printer, announced that they would be closing down the business and selling off the remaining inventory of products by the end of October. There was a reported mass layoff on October 11, with 90 of its 113 employees getting a pink slip. One of the employees filed a class-action suit in federal court, alleging that Aleph failed to give 60 days notice of terminations, which a company with more than 100 employees is required to do under federal law. As for the reason for the closure, nobody in the company’s leadership is commenting aside from the usual “streamlining operations” talk. Could it be that the flood of cheap 3D printers from China has commoditized the market, making it too hard for any manufacturer to stand out on features? If so, we may see other printer makers go under too.

For all the reported hardships of life aboard the International Space Station – the problems with zero-gravity personal hygiene, the lack of privacy, and an aroma that ranges from machine-shop to sweaty gym sock – the reward must be those few moments when an astronaut gets to go into the cupola at night and watch the Earth slide by. They all snap pictures, of course, but surprisingly few of them are cataloged or cross-referenced to the position of the ISS. So there’s a huge backlog of beautiful but unknown cities around the planet that. Lost at Night aims to change that by enlisting the pattern-matching abilities of volunteers to compare problem images with known images of the night lights of cities around the world. If nothing else, it’s a good way to get a glimpse at what the astronauts get to see.

Which Pi is the best Pi when it comes to machine learning? That depends on a lot of things, and Evan at Edje Electronics has done some good work comparing the Pi 3 and Pi 4 in a machine vision application. The SSD-MobileNet model was compiled to run on TensorFlow, TF Lite, or the Coral USB accelerator, using both a Pi 3 and a Pi 4. Evan drove around with each rig as a dashcam, capturing typical street scenes and measuring the frame rate from each setup. It’s perhaps no surprise that the Pi 4 and Coral setup won the day, but the degree to which it won was unexpected. It blew everything else away with 34.4 fps; the other five setups ranged from 1.37 to 12.9 fps. Interesting results, and good to keep in mind for your next machine vision project.

Have you accounted for shrinkage? No, not that shrinkage – shrinkage in your 3D-printed parts. James Clough ran into shrinkage issues with a part that needed to match up to a PCB he made. It didn’t, and he shared a thorough analysis of the problem and its solution. While we haven’t run into this problem yet, we can see how it happened – pretty much everything, including PLA, shrinks as it cools. He simply scaled up the model slightly before printing, which is a good tip to keep in mind.

And finally, if you’ve ever tried to break a bundle of spaghetti in half before dropping it in boiling water, you likely know the heartbreak of multiple breakage – many of the strands will fracture into three or more pieces, with the shorter bits shooting away like so much kitchen shrapnel. Because the world apparently has no big problems left to solve, a group of scientists has now figured out how to break spaghetti into only two pieces. Oh sure, they mask it in paper with the lofty title “Controlling fracture cascades through twisting and quenching”, but what it boils down to is applying an axial twist to the spaghetti before bending. That reduces the amount of bending needed to break the pasta, which reduces the shock that propagates along the strand and causes multiple breaks. They even built a machine to do just that, but since it only breaks a strand at a time, clearly there’s room for improvement. So get hacking!

Maker Spirit Alive And Well At The Philly Maker Faire

For many of us, it’s difficult to imagine a world without Maker Faire. The flagship events in California and New York have served as a celebration of the creative spirit for a decade, giving hackers and makers a rare chance to show off their creations to a live audience numbering into the hundreds of thousands. It’s hard to overstate the energy and excitement of these events; for anyone who had the opportunity to attend one in person, it’s an experience not soon forgotten.

Unfortunately, a future without Maker Faire seemed a very real possibility just a few months ago. In May we first heard the events were struggling financially, and by June, we were saddened to learn that organizer Maker Media would officially be halting operations. It wasn’t immediately clear what would happen to the flagship Maker Faires, and when Maker Media reluctantly admitted that production of the New York Faire was officially “paused”, it seemed we finally had our answer.

But as the recent Philadelphia Maker Faire proved, the maker movement won’t give up without a fight. While technically an independent “Mini” Faire, it exemplifies everything that made the flagship events so special and attracted an impressive number of visitors. With the New York event left in limbo, the Philadelphia Faire is now arguably the largest event of its type on the East Coast, and has the potential for explosive growth over the next few years. There’s now a viable option for makers of the Northeast who might have thought their days of exhibiting at a proper Maker Faire were over.

We’ll be bringing you detailed coverage of some of the incredible projects that were on display at the Philadelphia Maker Faire over the coming days, but in the meantime, let’s take a quick look at some of the highlights from this very promising event.

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Hackaday Podcast 040: 3D Printed Everything, Strength V Toughness, Blades Of Fiber, And What Can’t Coffee Do?

Hackaday Editors Mike Szczys and Elliot Williams opine on the coolest hacks we saw this week. This episode is heavy with 3D printing as Prusa released a new, smaller printer, printed gearboxes continue to impress us with their power and design, hoverboards are turned into tanks, and researchers suggest you pour used coffee grounds into your prints. Don’t throw out those “toy” computers, they may be hiding vintage processors. And we have a pair of fantastic articles that cover the rise and fall of forest fire watchtowers, and raise the question of where all those wind turbine blades will go when we’re done with them.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Direct download (59 MB)

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This Week In Security: A Digital Café Américain, The Linux Bugs That Weren’t, The Great Nation, And More

A government is going after a human rights activists in Morocco. It sounds familiar, but I don’t think Humphrey Bogart is running the gin joint this time around.

Questionable Casablanca references aside, Amnesty International has reported another attack against human rights workers. In this case, a pair of Moroccan activists were targeted with what appears to be NSO’s Pegasus malware suite. Researchers identified text message phishing that led to malicious web pages, as well as HTTP man in the middle attacks against their mobile devices. Once the target was successfully directed to the malicious site, A collection of zero-day vulnerabilities were used to compromise the phone with the NSO malware.

NSO is an Israeli company that specializes in building malware and other cybersecurity tools for governments. As you can imagine, this specialization has earned NSO the scorn of quite a few organizations. NSO claims to have a policy framework in place that allows them to evaluate and terminate the use of their software when it is deemed illegal or abusive, but due to the nature of their contracts, that process is anything but transparent. Continue reading “This Week In Security: A Digital Café Américain, The Linux Bugs That Weren’t, The Great Nation, And More”

Worried About Bats In Your Belfry? A Tale Of Two Bat Detectors

As somebody who loves technology and wildlife and also needs to develop an old farmhouse, going down the bat detector rabbit hole was a journey hard to resist. Bats are ideal animals for hackers to monitor as they emit ultrasonic frequencies from their mouths and noses to communicate with each other, detect their prey and navigate their way around obstacles such as trees — all done in pitch black darkness. On a slight downside, many species just love to make their homes in derelict buildings and, being protected here in the EU, developers need to make a rigorous survey to ensure as best as possible that there are no bats roosting in the site.

Perfect habitat for bats.

Obviously, the authorities require a professional independent survey, but there’s still plenty of opportunity for hacker participation by performing a ‘pre-survey’. Finding bat roosts with DIY detectors will tell us immediately if there is a problem, and give us a head start on rethinking our plans.

As can be expected, bat detectors come in all shapes and sizes, using various electrickery techniques to make them cheaper to build or easier to use. There are four different techniques most popularly used in bat detectors.

 

  1. Heterodyne: rather like tuning a radio, pitch is reduced without slowing the call down.
  2. Time expansion: chunks of data are slowed down to human audible frequencies.
  3. Frequency division: uses a digital counter IC to divide the frequency down in real time.
  4. Full spectrum: the full acoustic spectrum is recorded as a wav file.

Fortunately, recent advances in technology have now enabled manufacturers to produce relatively cheap full spectrum devices, which give the best resolution and the best chances of identifying the actual bat species.

DIY bat detectors tend to be of the frequency division type and are great for helping spot bats emerging from buildings. An audible noise from a speaker or headphones can prompt us to confirm that the fleeting black shape that we glimpsed was actually a bat and not a moth in the foreground. I used one of these detectors in conjunction with a video recorder to confirm that a bat was indeed NOT exiting from an old chimney pot. Phew!

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