Hackaday Links: November 3, 2013

November 3, 2013 by 3 Comments

hackaday-links-chain

[Michael] just missed the deadline for the Trinket Contest but we still think his tablet is pretty cool. He says it predates the iPad and uses a custom aluminum case, a SoC he ripped from a Gecko Edubook, powered by eight NiMH batteries. Check out the front, the guts, and the sides.

Speaking of portable power sources, After doing a teardown of a 12V 6800 mAh Li-Po battery [Howard] strapped some prototyping equipment to either side of it and now he’s got a prototyping power supply that’s easy to take with him.

Blinky goodness doesn’t have to look hacked together (even if it is). This Raspberry Pi logo looks like a professional sign! It was cut from foam and plastic, primed and painted, then stuffed with addressable LED strips.

While we’re on the topic of refined RPi projects, check out this Raspberry Pi MAME cabinet. It’s a bit bigger than the Galaga cabinet we saw recently but still small enough to keep around the house without getting in the way.

If you’re a fan of automotive hacks you should check out this effort to build an Electronic Diesel Control.

We’ve been saving the gnarliest link for last. [Matthew] laments that his missed Halloween to show off this project. But we don’t think an almost-entirely wooden spider-like walker needs to be paired with a holiday. It’s very cool and somewhat operational, but still needs help working out all of the kinks. Our favorite moment in the video is when [Matthew] exclaims “It wants to live!”.

Duo Basic: An All-Logic Chip Educational Computer

November 3, 2013 by 16 Comments

DUO

Way back before the days of microcomputers, a few very lucky students first got their hands wet with microcomputer trainers. These simple devices used common logic chips, lights, and switches to perform calculations; basically, a very small and simple computer. [Jack] has just released his DUO Basic 8-bit educational computer, a computer designed entirely around logic chips just as was done in the olden days.

The entire computer except for a single EEPROM giving the computer 256 bytes of ROM, three registers, and two instructions (condition jmp and add). This allows for simple programs to be written just by flipping switches and hitting buttons – it doesn’t get much more ‘bare metal’ than that.

[Jack] has an online assembler and emulator for the DUO Basic along with a few example assembly programs. Of course, all the schematics and block diagrams are available on his site, along with a nice introductory video, shown below.

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DIY Doggy Doorbell

November 3, 2013 by 16 Comments

doggy doorbell

Is your dog the strong silent type? Ever wish he or she could tell you when it is time to go do their business? This Reddit r/DIY user found a simple solution — a doggy doorbell!

The dog in question isn’t very vocal, so his owner sought a simple solution, similar to Pavlov’s bells — the only problem? He needed some range on it, as you can’t always hear a few bells throughout the entire house. The solution? A wireless doorbell that he repackaged into a dog friendly button!

Compared to our last post on an automatic pet watering system, this one is a very simple hack that requires absolutely no electrical experience. It could be improved upon quite easily though, by wiring a second switch in parallel so the dog can ring the doorbell from the outside of the house too!

According to the owner, it only took a few treats to get the pooch trained well enough to use it whenever he needs to go out!

[Via Reddit]

“Professor Kill A. Volt” Shocks Pumpkins With His Tesla Coil

November 3, 2013 by 23 Comments

jj

[JJ Dasher] is back again this year, shocking some pumpkins! (Volume warning). We featured [JJ] two years ago for his Halloween candy shocking Tesla coil. He apparently has been busy in his mad scientist laboratory doing some upgrades. This year his coil is producing 5 foot long streaming arcs!

[JJ’s] Tesla coil is a uses two microwave oven transformers as a power supply. He also uses an Asynchronous Rotary Spark Gap (ASRG). As the name implies, a rotary spark gap uses a motor to turn a rotor. At certain points in the rotation, the rotor creates a small enough gap that a high voltage spark can jump across, energizing the primary coil. This idea is similar to an automotive ignition system distributor. [Pete] gives a great example of an ASRG in this video. Most ASRG based Tesla coils use the small motor to spin up the spark gap. Varying the speed of the motor creates the characteristic “motor revving” noise heard in the final arcs of the Tesla Coil.

[JJ] made things a bit more interesting by installing a couple of fluorescent bulbs inside a pumpkin near the coil. The coil lights them easily, and they glow even brighter when the pumpkin is struck. Still not satisfied, he also donned his grounded chainmail gloves and drew the arc to himself. We always love seeing people safely taking hits from massive Tesla coils, but this definitely falls under the “don’t try this at home” banner.

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RFID Reader Snoops Cards From 3 Feet Away

November 3, 2013 by 60 Comments

Security researcher [Fran Brown] sent us this tip about his Tastic RFID Thief, which can stealthily snag the information off an RFID card at long range. If you’ve worked with passive RFID before, you know that most readers only work within inches of the card. In [Fran’s] DEFCON talk this summer he calls it the “ass-grabbing method” of trying to get a hidden antenna close enough to a target’s wallet.

His solution takes an off-the-shelf high-powered reader, (such as the HID MaxiProx 5375), and makes it amazingly portable by embedding 12 AA batteries and a custom PCB using an Arduino Nano to interpret the reader’s output. When the reader sees a nearby card, the information is parsed through the Nano and the data is both sent to an LCD screen and stored to a .txt file on a removable microSD card for later retrieval.

There are two short videos after the break: a demonstration of the Tastic RFID Thief and a quick look at its guts. If you’re considering reproducing this tool and you’re picking your jaw off the floor over the price of the reader, you can always try building your own…

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Make Your Own LED Lightbulb!

November 3, 2013 by 43 Comments

LED lightbulb

Do you like saving electricity? Who doesn’t!

Do you have a lot of LED light strips lying around, destined for a project that you never quite got around to? We’re guilty!

Do you have an old DC power adapter? Of course you do.

Do you love soldering? Duh.

Do you have a dead fluorescent light bulb sitting around? Maybe…

If so, here’s a quick and silly guide to making your very own LED light bulb! The result is a bit ghetto we admit, but quite functional. Perhaps it could be improved by adding a glass Christmas bobble to make it look a bit more like a regular light bulb. And if you’re ambitious enough you could throw a microprocessor in there and add wireless control to it as well … but let’s be honest, smart LED light bulbs are getting quite affordable these days. But hey, you’ve got to do something for entertainment!

Assassin’s Creed Hidden Blade

November 2, 2013 by 38 Comments

The youngins in the crowd may not remember Taxi Driver, but [Matt]’s fully functional hidden blade from Assassin’s Creed finally does justice to the hidden weapon on a drawer slide idea. It’s got everything you would want – immaculate craftsmanship and a video game reference for that every so necessary blog cred.

[Matt] started his hidden blade build with a drawer slide, mounting an old WWII replica blade to the slider. The blade retraction is spring-loaded, and with a small ring and a bit of wire, the blade gets its automatic draw and retraction.

The arm brace is where this project really shines. [Matt] crafted this out of two pieces of leather, tooled with the Assassin’s insignia and dyed to a deep, jet black

This isn’t the first time we’ve seen an automatic hidden blade from Assassin’s Creed, but [Matt]’s effort is really top-notch. He’s got beautiful leather crafting down pat, and we can only hope his Halloween was filled with parkour and stabbing.