Reinventing The Wheel

May 8, 2021 by Elliot Williams 62 Comments

You’ve got a perfectly working software library to do just exactly what you want. Why aren’t you using it? Some of you are already yelling something about NIH syndrome or reinventing the wheel — I hear you. But at least sometimes, there’s a good enough reason to reinvent the wheel: let’s say you want to learn something.

Mike and I were talking about a cool hack on the podcast: a library that makes a floppy drive work with an Arduino, and even builds out a minimalistic DOS for it. The one thing that [David Hansel] didn’t do by himself was write the FAT library; he used the ever-popular FatFS by [Elm-ChaN]. Mike casually noted that he’s always wanted to write his own FAT library from scratch, just to learn how it works at the fundamental level, and I didn’t even bat an eyelash. Heck, if I had the time, I’d want to do that too!

Look around on Hackaday, and you’ll see tons of hacks where people reinvent the wheel. In this superb soundbar hack, [Michal] spends a while working on the IR protocol by hand until succumbing to the call of IRMP, a library that has it all done for you. But if you read his writeup, he’s not sad; he learned something about IR protocols. This I2C paper tape reader is nothing if not a reinvention of the I2C wheel, but isn’t that the best way to learn?

Yes it is. Think back to the last class you took. The teacher or professor certainly explained something to you in reasonable detail — that’s the job after all. And then you got some homework to do by yourself, and you did it, even though you were probably just going over the same stuff that the prof and countless others have gone through. But by doing it yourself, even though it was “reinventing the wheel”, you learned the material. And I’d wager that you wouldn’t have learned it without.

Of course, when the chips are down and the deadline is breathing hot down your neck, that might be the right time to just include that tried-and-true library. But if you really want to learn something yourself, you have every right to reinvent the wheel.

Automate Your Poultry With CoopCommand

May 8, 2021 by Jenny List 24 Comments

A fresh egg taken from beneath a slumbering hen is something to which the taste of a supermarket equivalent rarely compares. The satisfaction of having a contented flock does come at a price though, in the form of constant monitoring and husbandry of your poultry’s well-being. It’s a problem that [hms-11] has tried to address with CoopCommand, a system to automate the monitoring of and environment within a chicken coop. It controls a light to counteract for shorter winter days, warms their water when it’s cold, has a fan for cooling and ventilation on hot days, and a camera to keep any eye on them.

At its heart is an ATmega328 controlling the coop functions, and an ESP32 camera board for network connectivity and visual monitoring. An alphanumeric LCD and a set or buttons provide the interface, and all is fitted on a custom PCB in a smart 3D-printed housing. Meanwhile all the files can be found in a GitHub repository.

A machine cannot replace human care and attention when it comes to good animal husbandry, as there’s always an essential need for the poultry owner to attend to the needs of their charges. But a system like this one can make an important contribution to their welfare, with a consequent increase in their laying ability.

A Dutch City Gets A €600,000 Fine For WiFi Tracking

May 8, 2021 by Jenny List 53 Comments

It’s not often that events in our sphere of technology hackers have ramifications for an entire country or even a continent, but there’s a piece of news from the Netherlands (Dutch language, machine translation) that has the potential to do just that.

Enschede is an unremarkable but pleasant city in the east of the country, probably best known to international Hackaday readers as the home of the UTwente webSDR and for British readers as being the first major motorway junction we pass in the Netherlands when returning home from events in Germany. Not the type of place you’d expect to rock a continent, but the news concerns the city’s municipality. They’ve been caught tracking their citizens using WiFi, and since this contravenes Dutch privacy law they’ve been fined €600,000 (about $723,000) by the Netherlands data protection authorities.

The full story of how this came to pass comes from Dave Borghuis (Dutch language, machine translation) of the TkkrLab hackerspace, who first brought the issue to the attention of the municipality in 2017. On his website he has a complete timeline (Dutch, machine translation), and in the article he delves into some of the mechanics of WiFi tracking. He’s at pains to make the point that the objective was always only to cause the WiFi tracking to end, and that the fine comes only as a result of the municipality’s continued intransigence even after being alerted multiple times to their being on the wrong side of privacy law. The city’s response (Dutch, machine translation) is a masterpiece of the PR writer’s art which boils down to their stating that they were only using it to count the density of people across the city.

The events in Enschede are already having a knock-on effect in the rest of the Netherlands as other municipalities race to ensure compliance and turn off any offending trackers, but perhaps more importantly they have the potential to reverberate throughout the entire European Union as well.

This POV Clock Combines A Nixie With A Pendulum

May 7, 2021 by Dan Maloney 6 Comments

Talk about your mixed timekeeping metaphors: there are clocks, and pendulum clocks, and there are Nixie clocks, and persistence of vision clocks. But this is a Nixie pendulum POV clock, and we think it’s pretty cool.

We first spied this on Twitter and were subsequently pleased to learn that [Jayzon Oeve] has posted a more detailed build log over on Hackaday.io. Rather than a moving array of dots to create the characters to display, this uses a single IN-12b Nixie tube at the end of a pendulum. The pendulum is kept moving by a small nudge created by a pulse through a fixed hard drive voice coil acting on a magnet affixed to the bottom of the pendulum — we’ve seen a similar approach used before.

Pretty much all of the electronics are mounted on the pendulum arm, including a Nano, an RTC, and an accelerometer to figure out where in the swing the bob is and when to flash a number on the display. There’s a video below that shows it at work both at full speed and in slow-motion; as always with POV clocks, these things probably look better in person than on video. And while swinging Nixies around like that seems a little dicey, we like the way this turned out.

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The Fine Structure Constant In A Blink

May 7, 2021 by Al Williams 8 Comments

Electronics is really an applied branch of physics, so it isn’t surprising that if you are serious about your electronics, you probably know a little physics, too. If you’ve ever heard the term “fine structure constant” and weren’t entirely sure what it means, [Parth G] wants to explain it to you in about a minute. His video explanation appears below.

You may know that the constant, often represented by α, is approximately 1/137, but what does that mean? The answer relates to the orbit of electrons. You might remember from school that electrons orbit in shells around the nucleus. That is, an atom might have some electrons in the innermost shell, and more electrons in an outer shell.

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K’nex Pinball Machine Is A Playable Work Of Art

May 7, 2021 by Kristina Panos 12 Comments

It’s really a wonder that we missed this one, what with all the extra time in front of a computer we’ve had over the last year or so. But better late than never, we always say, so behold, (a little at a time, because there’s quite a lot to look at), [Tyler Bower]’s pinball machine built entirely from K’nex.

Where do we even start? This is a full-size pinball machine, as in 7′ tall, 5′ long, and 3′ wide. [Tyler] estimates that it’s made from about 16,000 pieces, or around 73 pounds of plastic, much of which was obtained locally and is secondhand. Many of those pieces make up the ten drill motor-driven chain lifts in the back — these move the ball through the machine after it goes through one of the track triggers and return it to the playfield in various delightful ways.

Speaking of ways to score, there are nine of them total, and some are harder to get to than others. They all involve some really amazing K’nex movement, and each one uses aluminum foil switches to trigger scoring through a MaKey MaKey.

Of course there’s a multi-ball mode, but our favorite has to be the trap door in the playfield that gets you to the mini pinball game in the upper left, because only the best pinball games have some kind of mini game. Either that, or our favorite is the rotating arm that swings around gracefully and drops the ball on a track. Anyway, all nine elements are explored in the video after the break, which frankly we could watch on repeat. If you’re hungry for more details, there’s quite a bit of info in the description.

The only thing this machine is missing is a tilt switch, but as you’ll see in the video, it would probably get triggered quite often. Is this somehow not cool enough for you? Here’s a slightly bigger K’nex ball machine that doesn’t seem to move as much, but also isn’t a full freaking pinball machine complete with meta game.

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A Trip Down The Vacuum Clamping Rabbit Hole

May 7, 2021 by Dan Maloney 6 Comments

We all know how easy it is to fall down the rabbit hole, something that turns a seemingly simple job into an accidental journey of experimentation and discovery. And perhaps nobody is more prone to rabbit-holing than [Matthias Wandel], at least judging by his recent foray into quantitating different techniques for vacuum clamping in the woodshop. (Video, embedded below.)

To understand where this all came from, you’ll have to dial back to [Matthias]’s first video, where he was just trying to make a simple corkboard. In an effort to get even pressure over the whole surface of the board, he came up with a shop-expedient vacuum clamp, made from a sheet of thick plastic, some scraps of wood and clamps, and a couple of vacuums. With the workpiece sandwiched between a smooth, flat table and the plastic sheet, he was able to suck the air out and apply a tremendous amount of force to the corkboard.

The comments to the first video led to the one linked below, wherein [Matthias] aimed to explore some of the criticisms of his approach. Using a quartet of BMP280 pressure sensor breakout boards and a Raspberry Pi, he was able to nicely chart the pressure inside his clamping jig. He found that not only did the sensors make it easy to find and fix leaks, they also proved that adding a porous layer between the workpiece and the vacuum bag wouldn’t likely improve clamping. He was also able to show which of his collection of vacuums worked best — unsurprisingly, the Miele sucked the hardest, although he found that it wasn’t suitable for continuous clamping duty.

We can see a lot of uses for a jig like this, and we really like it when trips down the rabbit hole yield such interesting results. Especially quantitative results; remember [Matthias]’s exploration of basement humidity?

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