Lego Wheels And Tracks Benchmarked For Your Pleasure

May 4, 2021 by Lewin Day 7 Comments

For many people, Lego is their first entry into the world of engineering. With the Technic line of building blocks complete with all manner of gears and shafts and wheels, there’s a ton of fun to be had while learning about the basic principles of mechanical things. The [Brick Experiment Channel] takes Lego quite seriously in this context, and has collected data concerning the performance of a variety of Lego wheels and tracks.

The testing setup is simple. A small vehicle is fitted with a particular set of Lego wheels or tracks. Then, it’s placed on an inclined wooden board. The angle of inclination is then increased until the vehicle neither climbs the board nor slips down it. This angle can then be used to calculate the coefficient of friction of the given tyre or track set. [Brick Experiment Channel] filmed this testing and collected data on 33 different wheel and track combinations, publishing it in the description of the Youtube video.

Interestingly, the date of release of the various parts is recorded with the data. This is interesting as one would expect older rubber parts to lose grip with age, however, the release date of the parts obviously does not correspond with the manufacturing date, so the utility of this is somewhat unclear. There’s also some surprising results, with what appear to be soft, flat and smooth rubber wheels performing somewhat worse than those with curved profiles that you’d expect to have less contact patch. Regardless, it’s the best data we’ve ever seen in this field and we think it’s great that it was collected and shared with the broader Lego community. We look forward to seeing more of this in future, as it’s obviously something of great use to builders. We can imagine it would have proved handy when [Brick Experiment Channel] built their obstacle climbing rover. Video after the break.

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Enjoy An ASCII Version Of Star Wars In The Palm Of Your Hand For May The 4th

May 4, 2021 by Dan Maloney 13 Comments

Everyone by now has probably seen the original — and best; fight us — installment of the Star Wars franchise, and likely the ASCII-art animation version of it that improves greatly on the film by eliminating all those distracting special effects, human actors, and the soundtrack. But what we haven’t had until now is a portable player for ASCIIWars, to enjoy the film in all its character-based glory while you’re on the go.

While this tribute to [Simon Jansen]’s amazing ASCII-art achievement might seem like a simple repackaging of the original, [Frank] actually had to go to some lengths to make this work. After getting [Simon]’s blessing, the build started with a WEMOS D1 Mini, a good platform for the project less for its wireless capabilities and more for its 4 MB of flash memory. A 240×360 TFT LCD display was selected to show the film; the scale of the display made most fonts hard to read, so [Frank] used Picopixel, a font designed for legibility on small screens. The animation file is stored on the SPIFFS file system on the D1’s flash memory, and a few lines of code parse it and send it to the display. The final touch is mounting the whole thing is an old slide viewer, which magnifies the display to make it a little easier to see.

As much as we applaud [Frank]’s tribute to [Simon]’s effort, there’s no reason to confine this to the Star Wars universe. If you read up on the history of ASCII art, which goes surprisingly far back, you might be inspired to render another classic film in ASCIImation and put it on a viewer like this. ASCII-Metropolis, anyone?

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I2C Paper Tape Reader Is Not What You Think

May 3, 2021 by Chris Lott 26 Comments

We’re not quite sure what drove the development of this project, but [shapoco] has put together an intriguing device that reads I2C signals (Japanese Twitter link) which have been printed as black and white rectangles on paper tape. He wrote a program that prints an I2C byte stream onto strips containing the SCL and SDA signal patterns. Once printed, you cut the strips from the paper and glue them together into one long piece, making a complete message — in this case, commands to a small LCD screen that will display the phrase “Hello, Tape I2C”.

We’re not sure exactly sure what’s inside that rectangular widget epoxied to the bottom of that perf board through which the tape passes. But clearly, it must contain a pair of LEDs to illuminate the tape and a pair of sensors to detect the reflection off the tape (looking at the wiring, it seems unlikely that anything is mounted underneath the tape). According to one machine-translated Twitter message, detection is done using a Schmitt trigger made from an LM393 comparator with hysteresis (see this TI app note for a review of this type of circuit). Here’s a scope capture of the resulting signals. [Shapoco] notes that the circuit can operate much faster — the tape is being pulled slowly in the video to make it easier to see.

This is not [shapoco]’s first experiment in optical I2C communications. Check out the second video down below where he’s reading I2C signals from a computer’s display. One person tweeted about how software source code was sometimes printed optically in old Byte magazines many years ago, a topic we talked about in Hackaday Podcast #049 last year when discussing Cauzin strips.

Besides just being cool, and possibly helpful as an educational device, does this technique have any real-world applications these days? Let us know your thoughts in the comment section below. Thanks to [Manawyrm] for sending us this tip.

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Keep Livestock From Razing Your Field With An Overgrazing Shield

May 3, 2021 by Kristina Panos 49 Comments

You know, not every solution needs to be complicated to be absolutely awesome. Take the humble clothespin, for example, two pieces of cleverly carved wood (or plastic; we won’t judge) and a spring. And yet, the service it provides is useful for many applications.

The same simple elegance is also present in [Anteneh]’s overgrazing shield. When sheep and other animals are allowed to eat the vegetation down to the soil, it leads to soil erosion if not kept in check with regular grazing location rotation. As it turns out, if you want to keep an animal from eating grass and plants down to the soil, just slip a leather harness over its neck with a piece of wood in the right place so it literally can’t graze any lower than the wood allows.

According to [Anteneh]’s prototype tests, it only takes a few seconds to fit the shield to the animal’s head and neck, and then they’re off to grazing to the prescribed depth. We think this is a great solution and hope to see it in wide use along with regular rotation.

Need a way to track your livestock? [Sean Boyce]’s experiments with subcutaneous pig tracking makes for a good read, but the reality of that system will probably have you looking for a simpler solution.

Modding A Casio W800-H With A Countdown Timer

April 30, 2021 by Lewin Day 28 Comments

Stock, the Casio W800-H wristwatch ships with dual time modes, multiple alarms, and a stopwatch – useful features for some. However, more is possible if you just know where to look. [Ian] decided to dive under the hood and enable a countdown timer feature hidden from the factory.

The hack involves popping open the case of the watch and exposing the back of the main PCB. There, a series of jumpers control various features. [Ian]’s theory is that this allows Casio to save on manufacturing costs by sharing one basic PCB between a variety of watches and enabling features via the jumper selection. With a little solder wick, a jumper pad can be disconnected, enabling the hidden countdown feature. Other features, such as the multiple alarms, can be disabled in the same way with other jumpers, suggesting lower-feature models use this same board too.

It’s a useful trick that means [Ian] now always has a countdown timer on his wrist when he needs it. Excuses for over-boiling the eggs will now be much harder to come by, but we’re sure he can deal. Of course, watch hacks don’t have to be electronic – as this custom transparent case for an Apple Watch demonstrates. Video after the break.

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RC Ekranoplan Uses LIDAR To Fly In Ground Effect

April 29, 2021 by Lewin Day 33 Comments

Ekranoplans are a curious class of vehicle; most well known for several Soviet craft designed to operate at sea, flying just above the waves in ground effect. [rctestflight] had accidentally come across the ground effect flight regime himself years ago, and decided it was time to build an ekranoplan of his own.

I want to see little ekranoplans in at least three top 10 pop film clips by summer’s end. Please and thank you.

While ground-effect flight can be quite stable for a heavy, human-scale craft, the smaller RC version suffered more from minor perturbations from the wind and such. Thus, a Pixracer autopilot was installed, and combined with a small LIDAR device to accurately measure altitude above the ground. With some custom tweaks to the Ardupilot firmware, the craft was able to cleanly fly along barely a foot off the ground.

The final effect is almost mesmerizing; it appears as if the craft is hovering via some heretofore unknown technology rather than just flying in the usual sense. It’s still sensitive to breezes and sudden drops in the terrain lead to a temporary escape from the ground effect region, but the effect is nonetheless impressive. It’s a nerve wracking video at times, though, with quite a few near misses with traffic and children. Regardless of the nature of your experimental craft, be cognisant of your surroundings. We’ve seen [rctestflight]’s Ardupilot experiments before, too. Video after the break.

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Grinding Coffee Beans The Machine Shop Way

April 28, 2021 by Kristina Panos 31 Comments

Okay, so you bought a bag of heavenly-smelling single-origin beans down at the hipster coffee shop, but forgot to have them ground. What do you do? If you’re [Jimmy DiResta], there’s no way you can run down to Walmart and pick up a grinder for $15. You commune with your tools and spend a few hours building a grinder from stuff lying around in the workshop.

This hand-crank grinder would make a great post-apocalyptic appliance, as long as we still have a way to heat water. [Jimmy] started with an old manual abrasive disc grinder, like for grinding metal, not beans.

After oiling it up to run without a hitch, he pulled out a couple of conical gears and got to work mounting one to the grinder shaft and the other to the business part of a vintage industrial light fixture.

We thought for sure this was going to be a burr grinder, but were a bit disappointed to watch [Jimmy] drill holes through a utility knife blade in order to make a blade grinder. Honestly, we’re kind of surprised that he didn’t machine some burrs, but the result is impressive and lovely nonetheless.

We love that the whole thing quick-disconnects from the grinder thanks to a custom cuff that holds the light bulb just so, we just hope that [Jimmy] gave that light bulb a good cleaning first. Grab a cup of whatever and check out the build video after the break.

Not exactly your kind of shop? You could always print an emergency coffee grinder.

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