Pinball Stomp: part1

Despite my atrociously short attention span, I’ve always loved pinball. Maybe it is something about all the flashing lights and clunking solenoids. Maybe it is just the simple physics at the center of it all. I’m not really sure.  My kids, however, don’t share my enthusiasm. I suspect part of it is that they never wandered through a fog filled arcade in the middle of the night, hopped up on Reese’s Pieces with a shrinking pile of quarters in their pocket. The other part might be the fact that they have gotten used to the Nintendo Wii and the Xbox Kinect (we just got one last week).

Watching them jump up and down playing an extremely simple and repetitive game with the Kinect gave me an idea. I envisioned pinball projected on the side of my house, the kids jumping up and down in front of it to move the paddles. Keep reading to see how I plan to build it and what I’ve done so far. There’s a full video, but also text of the entire thing.
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3D whiteboard without the whiteboard

This one is so simple, and works so well, we’d call it a hoax if April 1st hadn’t already passed us by. But we’re confident that what [William Myers] and [Guo Jie Chin] came up with exists, and we want one of our own. The project is a method of drawing in 3 dimensions using ultrasonic sensors.

They call it 3D Paint, and that’s fitting since the software interface is much like the original MS Paint. It can show you the movements of the stylus in three axes, but it can also assemble an anaglyph — the kind of 3D that uses those red and blue filter glasses — so that the artists can see the 3D rendering as it is being drawn.

The hardware depends on a trio of sensors and a stylus that are all controlled by an ATmega644. That’s it for hardware (to be fair, there are a few trivial amplifier circuits too), making this an incredibly affordable setup. The real work, and the reason the input is so smooth and accurate, comes in the MATLAB code which does the trilateration. If you like to get elbow deep in the math the article linked above has plenty to interest you. If you’re more of a visual learner just skip down after the break for the demo video.

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Building new interfaces with an iPad

There’s a word – synchronicity – to describe two disparate events that occur together in a meaningful way. We see this a lot in the Hackaday tip line; two people send in somewhat similar hacks solving similar problems in similar ways nearly simultaneously. Here’s two builds by [Bryce] and [spektakx] that hit our inbox within minutes of each other that both implement existing interfaces with iPads.

iPad turntable controller

[spektakx] sent in an iPad powered DJ MIDI controller he built as a prototype to test out the size, orientation and layout for an upcoming build. The turntable controllers are simple USB affairs made to jog and scratch records digitally. Although [spektakx] admits it’s a little unfinished, it’s still just a prototype. Also, he can use a Windows 7 tablet laptop for ‘more suited’ hardware. Check out [spektakx]’ video demo after the break.

an iPad cash register

[Hacktheory] found [Bryce]’s Flickr photolog of a DIY ‘Square’ cash register. The electronics part of this build is practically non-existent; it’s just an iPad with a credit card readers that plugs into the headphone jack. Yes, we just saw these ‘Square’ credit card readers this last week. The fabrication portion of this build is incredible – [Bryce] has a few wonderful pieces of walnut there, and did an exceptional job with the wood work. It’s probably not well suited to high-volume retail, but we couldn’t think of a better cash register for a boutique shop.

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Miniaturized N64 controller fits the tiniest of hands

n64-controller-mod

The controllers that came with the Nintendo 64 don’t exactly measure up to the “Duke” of Xbox fame, but they’re not the smallest in the world either. Made by Bacteria forum member [Bungle] says that his girlfriend has incredibly tiny hands, so he thought he might try trimming some of the fat from an N64 controller by cramming its components into an N64 cartridge.

He tore down a 3rd-party N64 controller, tossing out the D-Pad, plug, and rumble motor, retaining all of the other buttons. After gutting the game cartridge, he heated the back side under a lamp and stretched the plastic over a roll of electrical tape to make room for the N64’s trademark “Z” button. Having only removed the rumble motor due to size constraints, he found a suitable replacement at Radio Shack, which fills in for the original nicely.

After a good amount of careful trimming, wiring, and mounting, he came up with the little gem you see above. We’re sure [Bungle’s] girlfriend is pleased with his work, and he seems happy with how it came out as well.

Continue reading to see a short video showing off [Bungle’s] latest creation.

[Thanks, Chris Downing]

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Reading credit cards with a tape head

A company called Square is giving out free credit card readers that turn any iPhone or iPad into a Point of Sale terminal. [Steve] got a hold of one of these tiny peripherals and did what any sane person would do: tear it apart and learn how it works. This bit of hardware is a little unimpressive; unsurprising because Square is giving them away. With simplicity comes an ease in understanding, and [Steve] was able to successfully read his own credit card with this tiny and free credit card reader.

[Steve]’s work in decoding credit card data builds off [Count Zero]’s article from the bbs days. Basically, each credit card has two or three tracks. Track three is mostly unused, whereas track one contains the card holder name, account number, cvc code and other ancillary data. Track two only contains the credit card number and expiration date.

The only components in the Square card reader are a head from a tape player and a 1/8″ microphone jack. The magnetic head in the Square card reader is positioned to only read track two. With a small shim, it’s possible to re-align the head to get the data from track one. After recording an audio file of him sliding his card though the Square reader, [Steve] looked at the number of times the waveform flipped from positive to negative. From this, he was able to get the 1s and 0s on the card and converted them to alphanumeric using the 6-bit ANSI/ISO alpha format.

[Steve] isn’t going to share the code he wrote for Android just yet, but it should be relatively easy to replicate his work with the Android tutorial he used. Also, yes, we did just pose the question of how these Square credit card readers work just hours ago. Good job being on the ball, [Steve]. Tips ‘o the hat go out to [Bobby], [Leif], [Derek] and anyone else we might have missed.

EDIT: [Stephen] sent in his teardown minutes after this post went live. Hackaday readers are too fast at this stuff.

An iTunes rating box for everyone

If you’ve ever scoffed at the idea of opening up iTunes every four minutes to rate a song, [Steve] is the guy to talk to. He built a small hardware box with five illuminated buttons to rate the current song playing on iTunes.

This build comes after [Steve]’s earlier Arduino-based rating box that was functional, but didn’t have the level of polish he desired. To get to the current iteration, [Steve] designed a custom board around a PIC18F microcontroller programmed as a USB HID device. After a great deal of frustration soldering teeny SMD components, [Steve] had a functioning USB five-star iTunes rating box. With a custom acrylic case the build was finally completed.

We’re very impressed with the finished version of [Steve]’s TuneConsole, as he calls it. We can certainly imagine other people wanting a similar device. Whether that comes from releasing the schematics and boards or selling PCBs on Seeed Studio is something we’re eager to find out.