Beyond Conway: Cellular Automata From All Walks Of Life

November 1, 2017 by Christian Trapp 23 Comments

There’s a time in every geek’s development when they learn of Conway’s Game of Life. This is usually followed by an afternoon spent on discovering that the standard rule set has been chosen because most of the others just don’t do interesting things, and that every idea you have has already been implemented. Often enough this episode is then remembered as ‘having learned about cellular automata’ (CA). While important, the Game of Life is not the only CA out there and it’s not even the first. The story starts decades before Life’s publication in 1970 in a place where a lot of science happened at that time: the year is 1943, the place is Los Alamos in New Mexico and the name is John von Neumann.

Recap: What is a CA?

The ‘cellular’ part in the name comes from the fact that CAs represent a grid of cells that can be in a number of defined states. The grid can have any number of dimensions, but with three dimensions the visual representation starts to get into the way, and above that most human brains stop working, so two-dimensional grids are the most common — with the occasional one-dimensional surprise. The cells’ states are in most cases discrete but a subset of continuous CAs exists. During the operation of a CA the future state of every cell in the grid is determined from each cells state according to a set of rules which in most cases take into account the states of neighboring cells.

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Mercy Me, Thanks For The Heals

November 1, 2017 by James Hobson 5 Comments

Sometimes, you have to call in the experts. [CorSec Props], builders of fine props, costumes and more, were commissioned to replicate Mercy’s healing staff from the game Overwatch. Sounds simple, but the customer — right as they always are — requested that it spin and light up just like the original.

To get a look at the electronics, the rotating head slides off after removing a screw. Inside, the rechargeable 18650 lithium-ion 3.7V battery — via a DC to DC converter — is bumped up to 5.5V in order to run a 12V, 120rpm motor. At full voltage the staff’s head rotates too fast, and so it’s deliberately under-powered for a more replica-appropriate speed.

A ring of RGB LEDs as well as a pair pointed at the tip of the staff toggle between yellow and blue hues. To switch between these different lighting modes, a double-pole, triple throw switch was modified to function like a more-suited-to-the-task-than-what-we-had-in-the-shop three position, double-pole, double-throw switch.

On the motor shaft, pair of studs slot into a piece of acrylic at the tip of the staff. This stops it from slipping, but also allows the LED glow to diffuse out the top as well as the portholes on the side of the staff. Check out the build after the break!

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Bluetooth Bedroom Clock!

November 1, 2017 by James Hobson 12 Comments

When [decino]’s old bedroom clock finally bit the dust, he built himself a new one from scratch for fun and functionality.

Initially, he wanted to solder Adafruit NeoPixel lights onto four prototype boards, using a mini-USB for power and a DS1307 to keep the time. However, after soldering the board for the first digit and realizing that carrying on with the other three would be a huge pain, he switched to etching the boards instead — a far more efficient solution. In keeping with this time-saving mindset, he added a Bluetooth module that would allow him to update the clock from his phone whenever the DS1307 started dropping minutes or whenever daylight savings time is in effect.

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Graphene Biosensors Are Extra Quiet

October 31, 2017 by Al Williams 9 Comments

Graphene has attracted enormous interest for electrically detecting chemical and biological materials. However, because the super material doesn’t act like a normal semiconductor, transistors require multiple layers of the material, and that’s bad for 1/f noise especially when the transistors operate at maximum transconductance. Researchers have found a way to operate graphene transistors at a neutral point, significantly reducing 1/f noise while not impacting the sensor’s response.

The team created a proof-of concept sensor that could detect an HIV-related DNA hybridization. The sensor was able to detect very tiny concentrations of the material.

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[Ben Krasnow] Hacks E-Paper For Fastest Refresh Rate

October 31, 2017 by Steven Dufresne 26 Comments

[Ben Krasnow] is known for his clear explanations alongside awesome hardware, being one of only a few hackers who owns an electron microscope. This time he’s explaining how E-paper works while modifying the firmware of a 4.2 inch E-paper module to get a higher refresh rate. As for the awesome hardware, he also analyses the signals going to the E-paper using an ultra-fancy loaner oscilloscope.

After starting out with a demo of the firmware in action before and after his modification, he explains how the E-paper works. The display is made up of many isolated chambers, each containing charged particles in a liquid. For example, the positive particles might be black and the negative might be white. By putting an electric field across each chamber, the white particles would be attracted to one end while the black would be attracted to the other, which could be the end you’re looking at. He also explains how it’s possible to get a third color by using different sized particles along with some extra manipulation of the electric field. And he talks about the issue of burn-in and how to avoid it.

Having given us that background, he then walks us through some of the firmware and shows how he modified it to make it faster, namely by researching various datasheets and subsequently modifying some look-up-tables.

Turning back to the hardware, he shows how he scratches out some traces so that he can attach scope probes. This alone seems like a notable achievement, though he points out that the conductive layer holds up well to his scratching. At that point he analyses the signals while running some demos.

The result is the very informative, interesting and entertaining video which you can watch below.

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Making Braille Signs Out Of PCBs

October 31, 2017 by John Baichtal 25 Comments

[jg] recently passed some damaged Braille signs and took on the challenge of repairing them. Informed by his recent work on PCB lapel pins, [jg] immediately thought of using circuit boards for this project. He’d noticed that round solder pads made for uniform hills of solder, and this reminded him of the bumps in Braille.

He began by reading up on the standards of the Braille Authority of North America, which stipulates a dot height of 0.6mm. He loaded up the PharmaBraille font system and laid it out the dots in photoshop, then and imported it into KiCad and laid out the boards. When the PCBs had arrived from OSH Park, [jg] soldering up the pads (lead free, but of course) to see if he could get the hills to 0.6mm. He’s experimenting with different methods of melting the solder to try to get more even results.

Braille interfaces crop up a surprising amount in hacker projects. This refreshable Braille display and keyboard and the Braigo LEGO Braille printer are prime examples.

[thanks, Drew!]

Homebuilt Laser Engraver Using Salvaged Parts

October 31, 2017 by Tom Nardi 25 Comments

Now that anyone can go online and get a fairly decent 3D printer for around $200, they’ve officially fallen out of the “Elite Hacker” arsenal and are now normal, if perhaps highly specialized, tools. That’s great for the 3D printing community as a whole, but what about those who want to be on the fringe of technology? Telling people you have a 3D printer at home doesn’t get that wide-eyed response like it used to. What’s a “l33t” hacker to do?

Enter the laser engraver/cutter: it’s like a 3D printer, but easier to build and has a higher capacity for bodily harm! While there are a couple good options for kits and turn-key setups out there, just like the early days of 3D printers, some of the best machines are still home built. In his latest video, YouTuber [MakerMan] takes us through his build which features an impressively low part count.

To start his build, [MakerMan] strips down four printers and salvages seven high quality 8 mm linear rods; a huge cost saving tip in itself. We’ll certainly be picking up any printers we see in the trash for the next couple months hoping to score some rods. With the addition of some cheap LM8UU bearings and 3D printed holders for them, [MakerMan] has a smooth 2D motion platform for just a couple bucks. The frame of the machine is built out of type of aluminum square tubing you can find at the hardware store, no expensive extrusion here.

For the laser itself, [MakerMan] is using a six watt PLH3D-6W-XF from Opt Lasers. This module features integrated driver and cooling, so all you need to do is provide it power and a stable means of moving it over the work piece. They even offer a magnetic “dock” which allows you to remove the laser from the mount without any tools for servicing or tool changes. [MakerMan] reports he’s been able to engrave stainless steel with this laser module, and cut thin wood.

This isn’t the first laser engraver we’ve seen built out of scrap parts, though if you want to save some work you could just upgrade a cheap commercial model.

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