Decoding Enigma Using A Neural Network

[Sam Greydanus] created a neural network that can encode and decode messages just as Enigma did. For those who don’t know, the Enigma machine was most famously used by the Germans during World War II to encrypt and decrypt messages. Give the neural network some encrypted text, called the ciphertext, along with the three-letter key that was used to encrypt the text, and the network predicts what the original text, or plaintext, was with around 96-97% accuracy.

The type of neural network he used was a Long Short Term Memory (LSTM ) network, a type of Recurrent Neural Network (RNN) that we talked about in our article covering many of the different types of neural networks developed over the years. RNNs are Turing-complete, meaning they can approximate any function. [Sam] noticed the irony in this, namely that Alan Turing both came up with the concept of Turing-completeness as well as played a big part in breaking the Enigma used in World War II.

How did [Sam] do it?

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Hackaday Prize Best Product Finalist: Shape Shifting Structures For Space

While [Elon Musk] and [Jeff Bezos] are working on getting us to Mars and the Moon, [Ronald Jaramillo] is working on building structures once we get there. To that end, he’s been developing the ZBeam, two rolls of links that zip together like a zipper to form a rigid beam.

ZBeam making, regolith munching machine
ZBeam making, regolith munching machine

Initially stored in a compact cube targeted to eventually fit in a CubeSat’s dimension’s, 100 mm x 100 mm x 100 mm, the beam emerges from within the cube and will be able to connect with other cubes to form rigid structures. His hope is that they can one day be made automatically from lunar or Martian regolith (loose surface dirt) munching machines. His current one has 160 mm sides and uses a servo hacked to turn continuously.

In his hackaday.io project logs he shows the trial and error he’s gone through to get to his current stage: experimenting with the links to form a more rigid beam, fine tuning the unreeling of the rolls of links to prevent jamming, adding a safety-ratchet-gear to the gearing to overcome speed issues, and more. He currently 3D prints as many connected sets of links as he can on his Prusa i3, and then manually connects sets together to make a longer chain, but he has his eye on the Printrbot Printrbelt for printing arbitrarily long chains in one piece.

You can see one pretty impressive iteration of the ZBeam in action in the video below and more is on his project page. In fact, the judges for the 2017 Hackaday Prize liked [Ronald]’s projects so much that they designated it as a Best Product finalist.

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Super Simple Hydraulics Using Syringes

When making a toy excavator arm, or any robotic arm, the typical approach is to put motors at the joints, or if there isn’t room, to put the motors somewhere else and transfer the force using fishing line and pulleys. [Navin Khambhala] chose instead to do it more like the real excavators, with hydraulics using syringes. And we have to admit, the result it pretty elegant in its simplicity.

The syringes do the job of single-acting hydraulic actuators, one at the motor and the other where the force is needed. In between them, what appears to be clear vinyl tubes carry the fluid between syringes. 12 volt DC motors with bolts on them move nuts attached to the syringe pistons to push and pull the pistons. It is so simple that no further explanation is needed, though like most apparently simple things, we’re sure a lot of effort went into making it that way. The video below shows the finished product, as well as walks through the making of it.

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Hackaday Prize Entry: Powered Running Stroller Keeps You Running

Types of strollers called ‘running strollers’ exist to make it possible to bring your toddlers along for your run but try it with two four-year old, 38 lb young ones, against the wind, and up enough hills and you’ll quickly lose steam. [Andrew Clink]’s and his wife’s solution? Modify the stroller to be a self-powered roadrunner.

[Andrew]’s hackaday.io build logs are detailed, including design, calculations, schematics, 3D printing files, fails and retries, and more. Power is provided by a bank of lithium-ion batteries that drive a brushless motor. The motor turns the stroller’s front wheel using a toothed belt around a small motor pulley and a larger 3D printed wheel pulley, providing a 13.92:1 gear ratio. [Andrew] considered a number of methods for steering, and even tried a few, but given that his paths are mostly straight lines, small adjustments by hand are all that’s needed. For the possibility of the stroller getting away from him for whatever reason, [Andrew] wrote an iOS app for his phone that makes use of the Bluetooth LE Proximity profile (PDF). It communicates with a small remote using an nRF8001 Bluetooth connectivity IC and for added safety has a belt clip and a stop button.

Does it work? See for yourself in the video below. We’re sure [Andrew] and his wife will continue to be fit for a long time to come.

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Earth Ground And The Grid

The electrical grid transmits power over wires to our houses, and our Bryan Cockfield has covered it very well in his Electrical Grid Demystified series, but what part does the earth ground play? It’s commonly known to be used for safety, but did you know that in some cases it’s also used for power transmission?

Typical House Grounding System

Grounding system normal case
Grounding system normal case

A pretty typical diagram for the grounding system for a house is shown here, along with a few of the current carrying conductors commonly called live and neutral. On the far left is the transformer outside the house and on the far right is an appliance that’s plugged in. In between them is a breaker panel and a wall socket of the style found in North America. The green dashed line shows the normal path for current to flow.

Notice the grounding electrodes for making an electrical connection with the earth ground. To use the US National Electrical Code (NEC) as an example, article 250.52 lists eight types of grounding electrodes. One very good type is an electrode encased in concrete since concrete continues to draw moisture from the ground and makes good physical contact due to its weight. Another is a grounding rod or pipe at least eight feet long and inserted deep enough into the ground. By deep enough, we mean to include factors such as the fact that the frost line doesn’t count as a good ground since it has a high resistance. You have to be careful of using metal water pipes that seemingly go into the ground, as sections of these are often replaced with non-metallic pipes during regular maintenance.

Notice also in the diagram that there are places where the various metal cases are connected to the grounding system. This is called bonding.

Now, how does all this system grounding help us? Let’s start with handling a fault.

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How To Turn An Animation Into A Soap Bubble Machine

Post an animation on Reddit of a workable machine that looks neat and does something cool and the next day someone will have built it. That’s what happened when [The-Big-Ship] uploaded an animation of a clever bubble making machine — though we had to look twice to convince ourselves that it wasn’t real. The next day [Over_Engineered_2] posted a video of his working one.

We often hear that you need precision CAD software such as Solidworks and AutoCAD to design a functional machine but the animation was done using Cinema 4D, used for films such as Iron Man 3 and Tron: Legacy. This shows that you can at least get a reassurance that the basic mechanics will fit and move together without having to design precision parts.

That’s not to say that reality didn’t interfere with implementing it though. In [Over_Engineered_2]’s video below he points out that the bigger ring of the original animation didn’t work with his small motor and propeller, and had to switch to the smaller ring. Also, note that the ring needed guide rails on the sides to keep it from twisting, something a real world ignoring animation can get away without. Check out the videos below to see the two in action.

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Raspberry Pi Trackpad From Salvaged Trackpad Plus Arduino

Old laptops are easy to find and many have a trackpad with a PS/2 interface hardwired into the guts of the laptop. [Build It] wanted one of those trackpads for use in the DIY Raspberry Pi laptop he’s working on. But the Raspberry Pi has no PS/2 input, and he read that a PS/2 to USB adapter wouldn’t be reliable enough. His solution? Wire the trackpad to an Arduino and have the Arduino convert the trackpad’s PS/2 to USB.

After removing a few screws, he had the trackpad free of the laptop. Looking up the trackpad’s part number online he found the solder pads for data, clock and five volts. He soldered his own wires to them, as well as to the trackpad’s ground plane, and from there to his Arduino Pro Micro. After installing the Arduino PS/2 mouse and the Mouse and Keyboard libraries he wrote some code (see his Instructables page). The finishing touch was to use generous helpings of hot glue to secure all the wires, as well as the Arduino, to the back to the trackpad. By plugging a USB cable into the Arduino, he now had a trackpad that could plug in anywhere as a USB trackpad. Watch [Build It] put it all together step-by-step in the video below.

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