First Raspberry Pi Zero Hack – Piggy-Back WiFi.

November 28, 2015 by Rud Merriam 122 Comments

And we have the first Raspberry Pi Zero hack! In less than 72 hours from the official release announcement [Shintaro] attached an Edimax WiFi USB Adapter directly to the USB solder pads on the Pi Zero. He couldn’t bear to disturb the small dimensions of the Pi Zero by using the USB On-the-Go (OTG). The OTG is needed to convert the micro-USB connector on the board to a full USB-A connector.

The case was removed from the Edimax and the device and Zero wrapped in Kapton to insulate the exposed solder points. Power was taken from the PP1 and PP6 points on the back of the board. These are the unregulated inputs from the USB power so should be used with caution. Some cheap USB power supplies can put out more that 5 volts when first connected and that might let the smoke out of a device.

The data wires were connected to PP22 and PP23, also on the back, and behind the USB data connector. Since USB is a differential signal these wires were carefully kept of equal length to avoid distorting the signal.

An SD card was created and edited on a Raspberry Pi B 2 to set the WiFi credentials. Inserted into the Zero it booted fine and started up the WiFi network connection.

Congratulations, [Shintaro] for the first Hackaday Raspberry Pi Zero hack. Is that a Hack-a-Zero-Day hack?

The Internet Of Reflow Ovens

November 28, 2015 by Al Williams 34 Comments

Using a toaster oven to reflow solder isn’t a new idea. But [Sukasa] wanted something that had more features and improved appearace. So he married a Netduino, a toaster oven, and some solid state relays to made a clean-looking reflow oven. His goal was to have nothing look like an overt modification to a casual observer. Inside, however, the oven now has a network connection for system status via a Web browser or JSON.

The new brains of the oven are a Netduino Plus 2 and an I2C port expander that connects to a few extra I/O devices. The challenging I/O, though, is the heaters. When cold, the oven can draw over 16 amps, so a pair of 12A solid state relays ~~in parallel~~ handle that load. There are also two fans: one to keep the electronics cool and another on software control. An IGBT allows the controller to pulse width modulate the fan’s output. A pair of MAX31855s read the thermocouples that report the temperature.

The controller was a mashup of the existing oven’s keypad and an add-on LCD display (see right). One thing we didn’t see was a schematic. Of course, you can read the code and figure out how it is all connected and (unless you use the exact same oven) you are probably going to need to modify things to suit your particular setup, anyway.

We’ve seen other good looking reflow oven and controller builds in the past, including one with a touchscreen. It is also worth noting that you can find reflow ovens at relatively low prices now if you don’t feel like rolling your own.

Thorough Macbook Charger Teardown Reveals Some Complex Circuitry

November 26, 2015 by Cameron Coward 86 Comments

Apple has a reputation in the tech world as being overpriced, and nowhere is that perception more common than in the Hackaday comments. The standard argument, of course, is that for a device with equivalent specs, Apple charges a lot more than its competitors. That argument is not without its flaws, especially when you consider factors other than simple specs like RAM and processor speed, and take into account materials used and build quality. But, as this teardown by [Ken Shirriff] shows, Apple’s attention to detail extends beyond simply machining Macbook bodies out of aluminum.

In his teardown, [Ken Shirriff] thoroughly investigates and describes all of the components and circuitry that go into the ubiquitous Macbook charger. Why does it cost $79? Other than the MagSafe connector, what makes it any better than the charger that came with your Toshiba Satellite in the ’90s? Isn’t it just a transformer to convert AC power to DC?

[Ken Shirriff] answers all of this and more, and you may be surprised by what he found. As it turns out, the Macbook charger isn’t just a transformer in a plastic case with a fancy magnetic connector. There is a lot of high-quality circuitry involved to make the power output as clean and stable as possible, and to avoid potential damage to your Macbook that could be caused by dirty power or voltage spikes. Does it justify the costs, even with so many reported failures? That’s for you to decide, but there is no questioning that Apple put more thought into their chargers than simply converting AC to DC.

Fail Of The Week: Dave Jones And The Case Of The Terrible Tablet

November 26, 2015 by Adam Fabio 74 Comments

Nothing spices up a quiet afternoon like the righteous indignance of an upset engineer, especially if that engineer is none other than [Dave Jones], on his EEVblog YouTube Channel. This week [Dave] has good reason to be upset. A viewer sent him what looked to be a nondescript 2010 era tablet from a company called Esinomed. From the outside it looked like a standard issue medical device. Opening up the back panel tells a completely different story though. This thing is quite possibly the worst hack job [Dave] (and we) have ever seen. This is obviously some kind of sales demo or trade show model. Even with that in mind, this thing is a fail.

The tablet is based upon an off-the-shelf embedded PC motherboard and touchscreen controller. [Dave] took some offense at the hacked up USB connector on the touchscreen. We have to disagree with [Dave] a bit here, as the video seems to show that a standard mini-b connector wouldn’t have fit inside the tablet’s case. There’s no excuse for the USB cable shield draped over the bare touch controller board though. Things go downhill from there. The tablet’s power supply is best described as a bizarre mess. Rather than use a premade DC to DC converter, whoever built this spun their own switch mode power supply on a home etched board. The etching job looks good, but everything else, including the solder job, is beyond terrible. All the jumps and oddly placed components make it look like a random board from the junk bin was used to build this supply.

The story gets even worse with the batteries. The tablet has horribly hand soldered NiMH cells shoved here, there and everywhere. Most of the cells show split shrink wrap – a sure sign they have been overheated. It’s hard to tell from the video, but it appears as if a few cells have their top mounted vent holes covered with solder. That’s a great way to turn a simple rechargeable battery into a pipe bomb. Batteries can be safely hand soldered – Radio Controlled modelers did it for decades before LiPo cells took over.

We’ve all hacked projects together at the last minute; that’s one of the things we celebrate here on Hackaday. However, since this is a commercial medical device (with serial number 11 no less) we have to stamp this one as a fail.

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The $5 Raspberry Pi Zero

November 25, 2015 by Brian Benchoff 329 Comments

Rumors about a new Raspberry Pi have been circulating around the Internet for the past week or so. Speculation has ranged from an upgraded Model A or compute module to a monster board with Gigabit Ethernet, USB 3.0, SATA and a CPU that isn’t even in production yet. The time is now, and the real news is even more interesting: it’s a $5 Raspberry Pi Zero. It’s the smallest Pi yet, while still keeping the core experience.

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Defeating Chip And PIN With Bits Of Wire

November 25, 2015 by Brian Benchoff 120 Comments

One of many ways that Americans are ridiculed by the rest of the world is that they don’t have chip and PIN on their credit cards yet; US credit card companies have been slow to bring this technology to millions of POS terminals across the country. Making the transition isn’t easy because until the transition is complete, the machines have to accept both magnetic stripes and chip and PIN.

This device can disable chip and PIN, wirelessly, by forcing the downgrade to magstripe. [Samy Kamkar] created the MagSpoof to explore the binary patterns on the magnetic stripe of his AmEx card, and in the process also created a device that works with drivers licenses, hotel room keys, and parking meters.

The electronics for the MagSpoof are incredibly simple. Of course a small microcontroller is necessary for this build, and for the MagSpoof, [Samy] used the ATtiny85 for the ‘larger’ version (still less than an inch square). A smaller, credit card-sized version used an ATtiny10. The rest of the schematic is just an H-bridge and a coil of magnet wire – easy enough for anyone with a soldering iron to put together on some perfboard.
By pulsing the H-bridge and energizing the coil of wire, the MagSpoof emulates the swipe of a credit card – it’s all just magnetic fields reversing direction in a very particular pattern. Since the magnetic pattern on any credit card can be easily read, and [Samy] demonstrates that this is possible with some rust and the naked eye anyway, it’s a simple matter to clone a card by building some electronics.

[Samy] didn’t stop there, though. By turning off the bits that state that the card has a chip onboard, his device can bypass the chip and PIN protection. If you’re very careful with a magnetized needle, you could disable the chip and PIN protection on any credit card. [Samy]’s device doesn’t need that degree of dexterity – he can just flip a bit in the firmware for the MagSpoof. It’s all brilliant work, and although the code for the chip and PIN defeat isn’t included in the repo, the documents that show how that can be done exist.

[Samy]’s implementation is very neat, but it stands on the shoulders of giants. In particular, we’ve covered similar devices before (here and here, for instance) and everything that you’ll need for this hack except for the chip-and-PIN-downgrade attack are covered in [Count Zero]’s classic 1992 “A Day in the Life of a Flux Reversal“.

Thanks [toru] for sending this one in. [Samy]’s video is available below.

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APRS Repeaters Get The Signal Out Of Mammoth Cave

November 25, 2015 by Elliot Williams 55 Comments

APRS Cave-Link uses the amateur radio’s Automatic Packet Reporting System (APRS) inside caves to get their position data (and other messages) out.

Imagine that you’re coordinating a large scale search-and-rescue mission in a cave. You need to know where all your groups are, and whether or not they’ve found anything. But how do they all communicate to the command center?

You’d guess radio, but you’d guess wrong. Radio doesn’t propagate well at all in a maze of twisty passages, all alike; rocks absorb radio waves, especially in the VHF/UHF range that’s best suited for most small radios. In the past, you’d run wire and transmit along it. This article runs through the options in detail. But adding miles of wire to your already heavy caving and climbing gear is a nuisance or worse.

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