Put A Little Pigeon In Your Next Clock Project

If you’re anything like us, you’ve probably wondered why gear teeth are shaped the way they’re shaped. But we’ll go out on a limb and say you’ve never wondered why gear teeth aren’t shaped like pigeons, and what a clock that’s not quite a clock based around them would look like.

If this sounds like it has [Uri Tuchman] written all over it, give yourself a cookie. [Uri] has a thing for pigeons, and they make an appearance in nearly all his whimsical builds, from his ink-dipping machine to his intricately engraved metal mouse. For this build, pigeons are transformed into the teeth of a large, ornate wheel, cut from brass using an impressive Friedrich Deckel pantograph engraver. To put the pigeon wheel to work, [Uri] built an escapement and a somewhat crooked pendulum, plus a drive weight and dial. It’s almost a clock, but not quite, since it doesn’t measure time in any familiar units, and the dial has a leg rather than hands — classic [Uri].

It may not be [Clickspring]-level stuff, but it’s still a lovely piece of work, and instructive to boot. The way [Uri] figured out the profile for the meshing teeth by looking at the negative space swept out by the pigeon profiles was pretty sweet. Plus, pigeons.

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Hackaday Links: March 15, 2020

Just a few weeks ago in the Links article, we ran a story about Tanner Electronics, the Dallas-area surplus store that was a mainstay of the hacker and maker scene in the area. At the time, Tanner’s owners were actively looking for a new, downsized space to move into, and they were optimistic that they’d be able to find something. But it appears not to be, as we got word this week from James Tanner that the store would be shutting its doors after 40 years in business. We’re sad to see anyone who’s supported the hardware hacking scene be unable to make a go of it, especially after four decades of service. But as we pointed out in “The Death of Surplus”, the center of gravity of electronics manufacturing has shifted dramatically in that time, and that’s changed the surplus market forever. We wish the Tanner’s the best of luck, and ask those in the area to stop by and perhaps help them sell off some of their inventory before they close the doors on May 31.

Feel like getting your inner Gollum on video but don’t know where to begin? Open source motion capture might be the place to start, and Chordata will soon be here to help. We saw Chordata as an entry in the 2018 Hackaday Prize; they’ve come a long way since then and are just about to open up their Kickstarter. Check out the video for an overview of what Chordata can do.

Another big name in the open-source movement has been forced out of the organization he co-founded. Eric S. Raymond, author of The Cathedral and the Bazaar and co-founder and former president of the Open Source Initiative has been removed from mailing lists and banned from communicating with the group. Raymond, known simply as ESR, reports that this was in response to “being too rhetorically forceful” in his dissent from proposed changes to OSD, the core documents that OSI uses to determine if software is truly open source. Nobody seems to be saying much about the behavior that started the fracas.

COVID-19, the respiratory disease caused by the newly emerged SARS-CoV-2 virus, has been spreading across the globe, causing panic and claiming lives. It’s not without its second-order effects either, of course, as everything from global supply chains to conferences and meetings have been disrupted. And now, coronavirus can be blamed for delaying the ESA/Russian joint ExoMars mission. The mission is to include a Russian-built surface platform for meteorological and biochemical surveys, plus the ESA’s Rosalind Franklin rover. Program scientists are no longer able to travel and meet with their counterparts to sort out issues, severely crimping productivity and forcing the delay. Social distancing and working from home can only take you so far, especially when you’re trying to get to Mars. We wonder if NASA’s Perseverance will suffer a similar fate.

Speaking of social distancing, if you’ve already decided to lock the doors and hunker down to wait out COVID-19, you’ll need something to keep you from going stir crazy. One suggestion: learn a new skill, like PCB design. TeachMePCB is offering a free rigid PCB design course starting March 28. If you’re a newbie, or even if you’ve had some ad hoc design experience, this could be a great way to productively while away some time. And if that doesn’t work for you, check out Bartosz Ciechanowski’s Gears page. It’s an interactive lesson on why gears look like they do, and the math behind power transmission. Ever wonder why gear teeth have an involute shape? Bartosz will fix you up.

Stay safe out there, everyone. And wash those hands!

Mechanisms: Gears

Even before the Industrial Revolution, gears of one kind or another have been put to work both for and against us. From ancient water wheels and windmills that ground grain and pounded flax, to the drive trains that power machines of war from siege engines to main battle tanks, gears have been essential parts of almost every mechanical device ever built. The next installment of our series on Mechanisms will take a brief look at gears and their applications.

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Star Track: A Lesson In Positional Astronomy With Lasers

[gocivici] threatened us with a tutorial on positional astronomy when we started reading his tutorial on a Arduino Powered Star Pointer and he delivered. We’d pick him to help us take the One Ring to Mordor; we’d never get lost and his threat-delivery-rate makes him less likely to pull a Boromir.

As we mentioned he starts off with a really succinct and well written tutorial on celestial coordinates that antiquity would have killed to have. If we were writing a bit of code to do our own positional astronomy system, this is the tab we’d have open. Incidentally, that’s exactly what he encourages those who have followed the tutorial to do.

The star pointer itself is a high powered green laser pointer (battery powered), 3D printed parts, and an amalgam of fourteen dollars of Chinese tech cruft. The project uses two Arduino clones to process serial commands and manage two 28byj-48 stepper motors. The 2nd Arduino clone was purely to supplement the digital pins of the first; we paused a bit at that, but then we realized that import arduinos have gotten so cheap they probably are more affordable than an I2C breakout board or stepper driver these days. The body was designed with a mixture of Tinkercad and something we’d not heard of, OpenJsCAD.

Once it’s all assembled and tested the only thing left to do is go outside with your contraption. After making sure that you’ve followed all the local regulations for not pointing lasers at airplanes, point the laser at the north star. After that you can plug in any star coordinate and the laser will swing towards it and track its location in the sky. Pretty cool.

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