Keep Livestock From Razing Your Field With An Overgrazing Shield

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

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

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

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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DIY Grader Box + Rocks = No Need For Shocks

Between the mini bike and the nearby woods, [HowToLou] has a lot for the rest of us to be envious of. Unfortunately, the terrain on the dirt path is too bumpy and uneven for a nice ride. But rather than spend hundreds to buy or rent an official grader box, [Lou] looked at his riding mower and said, I can do that myself (YouTube, embedded below).

This grader box is made from a heavy-duty oak pallet, plus a piece of particle board to complete the rocks box. [Lou] hooks up tow straps to the hooks and drags it behind the riding mower a few times to get the path nice and even. The line of lag bolts busts up the bumps, and the boards smooth out the surface under the weight of several large rocks. We think the result looks great, and doubt that [Lou] could have done any better with a fancy grader box. Check it out in action after the break.

Don’t have a riding mower? This is a pretty good excuse to buy one, but if that’s not in the cards, maybe you could build something suitable out of plywood and bike parts.

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Logic Flows, Literally, In This Water Adder

A lot of elementary electronic texts use water as an analogy for electricity. You know, pressure is voltage, flow is current, and pipe diameter is resistance. It is ironic, then, that some people use fluids to build logic gates and, in fact, you can make any logic circuit you like using nothing but water flowing through some structures. Don’t think so? Have a look at the video from [Steve Mould] below.

Fluidic logic isn’t anything new, but it has always been a bit exotic. Usually, replacing electrons with water or even air — which is a kind of fluid — means you are trying to operate in a tough environment or have some other special need. As far as we can tell, [Steve] did it just because he could, and we get that.

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3D-Printed Laser Scanning Confocal Microscope Measures Microns

When one thinks about microscopy, it seems to be mostly qualitative. Looking at a slide teeming with bacteria or protozoans is less about making measurements and more about recognizing features and describing their appearance. Not all microscopes are created equal, though, with some being far more optimized for making fine measurements of the microscopic realm.

This 3D-printed confocal laser scanning microscope is a good example of an instrument for measuring really small stuff. As [Zachary Tong] points out, confocal scanning microscopy uses a clever optical setup to collect light from a single, well-defined point within a sample; rather than getting an image of all the points within a two-dimensional focal plane, the scanning function moves the focal point around through the sample in three dimensions, capturing spatial data to go along with the optical information.

The stage of [Zach]’s microscope is based on OpenFlexure’s Delta Stage, an open-source, 3D-printed delta-bot motion control platform that’s capable of positioning samples with sub-micron precision. Above the stage are the deceptively simple optics, with a laser diode light source, an objective lens, and a photodiode detector behind a pinhole. The detector feeds a homebrew trans-impedance amplifier that captures data at millions of points as the sample is moved through a small three-dimensional space. All that data gets crunched to find the Z-axis position corresponding to the maximum intensity at each point.

It takes a while to gather all this data — up to several days for even a small sample — but it works pretty well. [Zach] already has some ideas for reducing noise and speeding up the scan time; perhaps a stage based on DVD parts like this one would be faster than the delta stage. We look forward to seeing his improvements.

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