Lawn From Hell Saved by Mower From Heaven

It’s that time of year again, at least in the northern hemisphere. Everything is alive and growing, especially that narrow-leafed non-commodity that so many of us farm without tangible reward. [sonofdodie] has a particularly hard row to hoe—his backyard is one big, 30° slope of knee-ruining agony. After 30 years of trudging up and down the hill, his body was telling him to find a better way. But no lawn service would touch it, so he waited for divine inspiration.

And lo, the answer came to [sonofdodie] in a trio of string trimmers. These Whirling Dervishes of grass grazing are mounted on a wheeled plywood base so that their strings overlap slightly for full coverage. Now he can sit in the shade and sip lemonade as he mows via rope and extension cord using a mower that cost about $100 to build.

These heavenly trimmers have been modified to use heavy nylon line, which means they can whip two weeks’ worth of rain-fueled growth with no problem. You can watch the mower shimmy down what looks like the world’s greatest Slip ‘n Slide hill after the break.

Yeah, this video is two years old, but somehow we missed it back then. Ideas this fresh that tackle age-old problems are evergreen, unlike these plots of grass we must maintain. There’s more than one way to skin this ecological cat, and we’ve seen everything from solar mowers to robotic mowers to mowers tied up to wind themselves around a stake like an enthusiastic dog.

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High End PC Gets A Rustic Woodworking Piece Of Art For A Case

As [Matt] from [DIY Perks] was about to assemble a new PC, he decided to take a unique direction when it came to building a case. Despite the appearance of a woodworking piece with weird industrial radiators, there is actually a full-fledged, high-end PC hidden inside.

Those radiators are a pair of almost-the-biggest-you-can-buy heatsinks — one of which has been modified to fit the graphics card. Separating the graphics card’s stock cooling fan unit cut down significantly on noise and works with the stringent space requirements of the build. Those fans however keep other components on the card cool, so [Matt] cut pieces of copper plate to affix to these areas and joined them to the heatsink with a heat pipe, bent to shape. The elm wood case then began to take shape around the graphics card — cut into pieces to accommodate the heat pipes, and sealed with black tack to dampen the ‘coil whine’ of the GPU; it turns out the likely culprit are the MOSFETs, but close enough.

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Mechanisms: Mechanical Seals

On the face of it, keeping fluids contained seems like a simple job. Your fridge alone probably has a dozen or more trivial examples of liquids being successfully kept where they belong, whether it’s the plastic lid on last night’s leftovers or the top on the jug of milk. But deeper down in the bowels of the fridge, like inside the compressor or where the water line for the icemaker is attached, are more complex and interesting mechanisms for keeping fluids contained. That’s the job of seals, the next topic in our series on mechanisms.

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LEGO Technics Machine Produces True Braided Rope

We love a good LEGO build as much as anyone, but Technics takes it to the next level in terms of creating working mechanisms. And nobody takes Technics as far as [Nico71], as evidenced by his super-fast Technics rope braiding machine.

The last time we saw one of [Nico71]’s builds, it was also a LEGO Technics rope-making machine. At the time, we called it a “rope-braiding machine” and were taken to task in the comments since the strands were merely twisted to make the final product. [Nico71] must have taken that to heart, because the current build results in true braided cordage. That trick is accomplished by flying shuttles that are not attached to either of the two counter-rotating three-spoked wheels. The shuttles are transferred between the two wheels by a sweeper arm, each making a full revolution with one wheel before being transferred to the other. Each shuttle’s thread makes an intertwining figure-eight around the threads from the two fixed bobbins, and the result is a five-strand braided cord. The whole machine is mesmerizing to watch, and the mechanism is silky smooth even at high speeds. It seems like a much simpler design than the previous effort, too.

You’ve got to hand it to builders like [Nico71] that come up with fascinating machines while working within the constraints of the Technics world. And those that leverage the Technics platform in their builds can come up with pretty neat stuff, like this paper tape reader for a music machine.

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Rope Braiding Machine Built Entirely from LEGO Technics

If you’ve ever seen a rope-braiding machine in action, you know they’re amazing machines where bobbins of thread whirl and spin in a complex dance to weave the threads under and over each other. Building one of these machines must be incredibly difficult; building one out of LEGO Technics pieces is darn near insane.

[Nico71], as hardcore a Technics builder as they come, tackled this complex build and made it work. A large drum spins horizontally and carries three groups of three planetary-mounted thread bobbins. The entire drum spins in one direction while the bobbins and another die with three holes spin the other way. The resulting braids are then fed through another spinning die, and the resulting 9-strand rope is taken up by a winding drum. The drum has a self-reversing feeding mechanism to keep the finished spool neat and tidy. The most impressive thing about the build, though, is the fact that it’s all powered by a single motor, and that everything is synchronized via gears, shafts, sprockets, chains and clutches. It’s a Technics tour de force you can see in action after the break.

[Nico71]’s build are pretty amazing. Some are pure art, others are models of classic cars and motorcycles, but things like his loom and the calculator he’s working on now are remarkable. Of course if you need to see more of the mesmerizing ballet of rope-braiding machines, check out this 16-bobbin hand-cranked version.

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16-Bobbin Rope Braiding Machine Inspired by Surplus Store Find

When the Red Bull Creation build days were past, [David] pulled us aside and asked if we wanted to see the mechanical hack he’s been working on. He built this rope braiding machine, which uses 16 bobbins, with help from his brother [Jed].

Ideas for projects always come from funny places. [David] came up with this one after finding a rope braiding machine at Ax-man Surplus. This outlet, located in the Twin Cities (Minneapolis/St. Paul, Minnesota) has been the origin for innumerable hacks. Just one that comes to mind is this electric scooter project from the ’90s.

[David] wanted to understand how the mechanism, which divides the bobbins up into groups of orbiting spools, actually works. It’s both mesmerizing and quite tough to visualize how it works without really getting in there and looking at the gearing. Thankfully you can do just that if he follows through with his plan to turn this into a kit.

In case you don’t recognize him, [David] was on the 1.21 Jigawatt’s team during this year’s Creation. We’ve also seen a couple of hacks from him in the past like this half-tone drum printer, and this bicycle frame welding jig.

Dilemmabox brings tactile upvoting

Here’s a fun art installation which you might run into downtown. It’s called the Dilemmabox and lets you pull a rope to up or down vote a question. [Christoffer Lorang Dahl] realized that touchscreens are wiping out a lot of really fun user interfaces of yore. He incorporated the two hanging rope inputs as an homage to doorbell ropes.

The built process works much like a laptop-to-digital photo frame conversion. The first step is to liberate the LCD screen from the laptop body. Both are housed in a wooden box, with a window cut out to show the screen. The mechanically clever part is the rope pulls. They’re both just pressing a key on the keyboard in a roundabout sort of way. [Christoffer] attached a smooth hemispherical piece to two keys. The ropes are connected to wooden levers which are held in place by springs. They rub on the hemispheres just enough when passing by to register a keypress.

The photo above was taken during the Dilemmabox’s brief appearance at a shopping plaza in Oslo.