Hackaday Links: October 5th, 2014

Good news from CadSoft this week. They didn’t miss all the complaints about their decision to use a Node Lock License for EAGLE 7. This had meant that users of the popular PCB design software would be limit on how many machines they could use the software with a license. They have removed License Management from the package (and all the citizens rejoiced).

We’re tripping over the growing pile of hardware that boast the “next-big-thing” in getting devices onto a network. That’s not a complaint at all. This time around it’s a cell chip, the U-blox SARA-U260, which can connect to 3G on the AT&T network and is just 16x26mm. They call it world’s smallest but we have no idea if that’s true or not. Anyone have a source and/or pricing for these? [Thanks Austin]

This guy loves his Nixie tube. How much? To the extent that he built up a hardware and software interface that behaves much like a pet. It’s voice activated, and the infectious delight of [Glasslinger’s] video demo is in itself worth watching. [Thanks Morris]

Making this Magnetic Stripe Reader work as a USB device is really nothing more than adding a serial-to-USB converter. The journey to find the way to add the converter makes for a fun read though.

We know from watching Breaking Bad that you can kill power to a building by shorting the power lines outside with a huge bouquet of mylar balloons. This installation is a twist on the idea. Connecting one mylar balloon to a Van de Graaff generator and floating it next to another results in an oscillating repel-discharge-repel cycle. [Thanks filnt via NPR]

Generating music with credit cards


[Steve] was browsing around at a local electronics surplus store when he spotted an old Tranz 330 point-of-sale terminal that seemed pretty interesting. He took it home and after disassembling it, found that it contained a Z-80 based computer. Because the 330 shares the same processor as other hobbyist-friendly devices such as the TRS-80, he figured it would be quite fun to hack.

While the Z-80 processor is pretty common, [Steve] still had to figure out how it was interfaced in this particular device. After spending some time reverse engineering the terminal, he had free reign to run any program he desired. After thinking for a bit, he decided it would be cool to use the terminal to generate music based on whatever card was swiped through the reader – he calls his creation “Mozart’s Credit Card”.

He found that just playing sounds based on the raw contents of the mag strips didn’t produce anything coherent, so he wrote a small application for the terminal based on the Melisma Stochastic Melody Generator. Music is generated somewhat randomly using various card characteristics, as you can see in the video below.

We think it’s pretty cool, but [Steve] says he’s always open to suggestions, so let us know what you think in the comments.

Continue reading “Generating music with credit cards”

Surprisingly simple magnetic card spoofer

[Craig’s] magnetic card spoofer is both simple and brilliant. There are two parts to spoofing these cards and he took care of both of them. The first part is getting the actual card data. He designed the spoofer board with a header that connects to a card reader for doing this. The second part is the spoofing itself, which is done with an electromagnet. As with past spoofers, he wrapped a shim with enamel-coated magnet wire. An old knife blade was picked for its thickness and ferromagnetism.  This magnet is driven by an ATtiny2313 which stores the data, and is protected by a transistor driving the coil. There were a few design flaws in his board, but [Craig] was able to get the same track data out of the spoof as the original card despite the LED being used as a protection diode and an ‘aftermarket’ resistor on the transistor base.

Magnetic card stripe spoofer

This hodge-podge of components is capable of spoofing the magnetic stripe on a credit card. [Sk3tch] built an electromagnet using a ferrous metal shim wrapped in enameled magnet wire. While he was doing the windings [Sk3tch] connected his multimeter to the metal shim and one end of the wire, setting it to test continuity. This way, if he accidentally scraps the enamel coating and grounds the wire on the metal the meter will sound and alarm and he’ll know about the short immediately. An Arduino takes over from here, actuating the coil to simulate the different data sections of a magnetic stripe.

From his schematic we see that the electromagnet is directly connected to two pins of the Arduino. We haven’t looked into the code but is seems there should be either some current limiting, or the use of a transistor to protect the microcontroller pins (we could be wrong about this).

[Sk3tch’s] realization of this spoofer can be made quickly with just a few parts. Card data must be written in the code and flashed to the Arduino. If you want to see what a more feature-rich version would entail take a look at this spoofer that has a keypad for changing data on the go.

[via Lifehacker]