A Very Modern Turing Machine Build

Mathematicians. If you let them use the concept of infinity, there’s almost nothing they won’t be able to prove. Case in point: the Turing machine. The idea is that with an infinite length of tape, one could build a thought-experiment machine with only a few instructions that should be able to compute anything that’s computable.

[Igor]’s Turing machine is one of the nicest we’ve ever seen built. The “tape” is significantly shorter than infinity, which limits the computations he can achieve, the use of 3D printing, electric contacts, and WS2812 RGB LEDs for the tape are profoundly satisfying.

A bit on the tape is portrayed as unused if the LED is off, zero if it is red, and one if it is green. Each station on the tape is indexed by a set of blue LEDs observed by the gantry of the writing head which uses a 3D printed finger and motor to change the state of each bit. Programs are stored on a home-built punch card, which gets extra geek points from us.

Watch it run through “busy beaver” (embedded below) and tell us that it’s not awesome, even if it is a couple of LEDs short of infinity.

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Neural Network Targets Cats with a Sprinkler System

It’s overkill, but it’s really cool. [Bob Bond] took an NVIDIA Jetson TX1 single-board computer and a webcam and wirelessly combined them with his lawn sprinklers. Now, when his neighbors’ cats come to poop in his yard, a carefully trained neural network detects them and gets them wet.

It is absolutely the case that this could have been done with a simple motion sensor, but if the neural network discriminates sufficiently well between cats and (for instance) his wife, this is an improved solution for sure. Because the single-board computer he’s chosen for the project has a ridiculous amount of horsepower, he can afford to do a lot of image processing, so there’s a chance that everyone on two legs will stay dry. And the code is up on GitHub for you to see, if you’re interested.

[Bob] promises more detail about the neural network in the future. We can’t wait. (And we’d love to see a sentry-turret style build in the future. Think of the water savings!)

Via the NVIDIA blog, and thanks [Jaqen] for the tip!

Cheap and Effective Dune Buggy Wheel Chair

[masterfoo]’s mother-in-law suffers from a bad hip which would have sidelined her participation in the Fourth of July festivities. As a testament to the power of family and ingenuity, [masterfoo] built her a beach-capable wheel chair to give her some off-roading capability.

The frame is built out of 1.5″ PVC piping and the tires are 20×8-8″ inner tubes for ride-on lawnmowers. The lawnmower  wheel inner tubes were cost-effective and fit the purpose, saving the need for the more expensive purpose-built-for-the-beach Wheeleez tires. They also have a fluid inside that plugs small punctures which will come in handy against he beach’s small cacti and other flora. This video was their guide for the foam insulation and plywood wheel assembly, also employing the handy man’s secret weapon to protect the tube from the rim’s plywood edge. Check it out in action!

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Build A Circular Aerofoil Kite

[Waalcko] fell in love with kites when he was 13 years old. He saw a NASA Para Wing kite fly and couldn’t get it out of his head. Now, years later, he shares how to build a circular foil kite design he came up with.

We’re all particular about our chosen hobbies. Some of us like one design direction and hate another. For [Waalcko], he really hates internal supports in kites. When he spied a single line kite in a circular foil configuration he was enraptured, but the design had those hideous spars. So, he got to work and pushed himself to the limit coming up with a kite that was a circular foil, flew with one line, and had no internal supports.

His instructable is a great read and goes into deep detail about the basics of kite construction. (After reading it we’re certain that even the shallows have depths when it comes kites.) It goes through the terminology used when talking about kits, the techniques used to assemble them, the common problems, and more.

Many hours later, if all goes well, one should end up with a really cool kite.

Refurbishing Armored Tablets

Who can resist the insane deals on bizarre hardware that pop up on auction websites? Not [Dane Kouttron], for sure. He stumbled on Armor X7 ruggedized tablets, and had to buy a few. They’d be just perfect for datalogging in remote and/or hostile locations, if only they had better batteries and were outfitted with a GSM data modem… So [Dane] hauled out his screwdrivers and took stuff apart. What follows is a very detailed writeup of the battery management system (BMS), and a complete teardown of this interesting tablet almost as an afterthought.

First, [Dane] tried to just put a bunch more batteries into the thing, but the battery-management chip wouldn’t recognize them. For some inexplicable reason, [Dane] had the programmer for the BMS on-hand, as well as a Windows XP machine to run the antiquated software on. With the BMS firmware updated (and the manufacturer’s name changed to Dan-ger 300!) everything was good again.

Now you may not happen to have a bunch of surplus X7 ruggedized tablets lying around. Neither do we. But we can totally imagine needing to overhaul a battery system, and so it’s nice to have a peek behind the scenes in the BMS. File that away in your memory banks for when you need it. And if you need even more power, check out this writeup of reverse-engineering a Leaf battery pack. Power to the people!

Looptaggr: Endless Graffiti

If your problem is how to put out a maximum amount of repetitive graffiti with a minimum amount of effort, we’ve got your solution. Or rather, [Ariel Schlesinger] and [Aram Bartholl] had your solution way back in 2010. The banner image says it all.

Of course, it doesn’t have to be graffiti that you’re spraying. This idea could be easily adapted to stencil that repeating floral pattern that my grandmother had on her walls too. It’s like a patterned paint roller, but for a spray can.

There’s room for improvements here. For instance, we can’t cut out stencils to save our life but we know where to find a laser cutter. From the look of things, they could use a slightly bigger stencil and something to catch the drips. There’s probably an optimal size for this gizmo, which calls for experimentation.

We’re somewhat obsessed with graffiti machines. Whether it’s a graffiti quadcopter or the elegant and non-permanent sidewalk-chalker style bots, we like machines that make “art”. What’s your favorite graffiti hack?

Thanks [n0p;n0p;n0p;] for the (archival) tip!

Mechanical Horse-Bike

Oh [Rodger Cleye]! You had us at “unicycle, duct tape, styrofoam, and tie wraps”. But watching the horse-bike in action (video below) is just about enough for us to go out and make one ourselves. (For our child, naturally. We’re far too dignified.)

If you trawl around [Rodger]’s YouTube channel, you’ll see no end of odd motorized vehicles. Like last year’s motorized horse project, or this stormtrooper speeder. But there’s just something about the way that the horse’s legs move along with the rider that is slightly more enchanting. (That’s the “unicycle” part of the build.) And, we assume, the rider gets a little bit more exercise to boot.

We’ve featured a few builds of [Rodger]’s before, including his motorized couch build that’s obviously controlled from the seat-mounted coconut, and of course a pneumatic Boba Fett rocket.