Hackaday Links: September 22, 2013

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First we start with some protection… for your USB charged devices. Here’s a USB Condom which acts as a pass-through for the power rails but not the data lines. This prevents untrusted charger security exploits. [Thanks Markus]

[OutKastz] seems to think he’s uncovered a price matching conspiracy at Best Buy. His post references an HDTV video wall he has built. But he also discovered that there are two different version of the same television sold as the same SKU. His theory is that this prevents the big box from matching prices on half of their inventory.

When you’re in need of some breadboarding action with your Raspberry Pi and want to make it as painless as possible you need to build your own Pi Cobbler. This is the diy version of an Adafruit product, built using a couple of pin headers, stripboard, and an IDE cable.

Speaking of Adafruit, did you see Ladyada’s teardown of an ICEdot crash sensor?

[Phineas] is showing off a really really small hexacopter. Check out the maiden flight, as well as first indoor and first outdoor tests.

Perhaps this coded entry system will inspire a future project for you. It uses piezo elements to enter a code which unlocks the back door to the company. The glass door already had a series of large dots painted on it. This turns out to be a nice interface for a four button code system.

Many projects use a Raspberry Pi as a web server. But there is more than just one flavor available. [Jeremy Morgan] performed a variety of Pi server benchmarks using Nginx, Monkey, Lighttpd, and Apache. [Thanks Walter]

Can an old TV antenna reflector be used to boost the range of a WiFi dongle? We’re a bit skeptical. Let us know what you think in the comments.

And finally, we do wish there was more information on this upright piano used to play Doom [Thanks Itay].

 

Stealth Peephole Camera Watches Your Front Door

In this week’s links post we mentioned an over-powered DSLR peephole that purportedly cost $4000. So when we saw this tip regarding a relatively inexpensive digital peephole, we thought some of you might be a bit more interested.

The hardware is quite simple; a decent webcam, a Raspberry Pi, and a powered USB hub. The camera gets stripped down to its PCB and hidden inside the door itself. Even if you see this from the inside it’s just a suspicious-looking wire which wouldn’t make most people think a camera was in use.

On the software side of things, [Alex] set up his Raspberry Pi as a 24/7 webcam server to stream the video online. Unlike using a cheap wireless CCTV camera, his video signals are secure. He then runs Motion, a free software motion detector to allow the camera to trigger events when someone comes sneaking by. It can be setup to send you a text, call you, play an alarm, take a picture, record a video… the list goes on. His blog has a full DIY guide if you want to replicate this system. We just hope you have a stronger door!

We covered a similar project back in 2011, but it had made use of real server instead of an inexpensive Raspberry Pi.

[Thanks Alex!]

Giant Video Walls Powered By A Raspberry Pi

There’s no denying that giant video walls are awesome, but creating one usually means a fairly complex setup with either multiple computers or very expensive video cards. Now, with Pi Wall, you can make a video wall as large as your wallet will allow with only one Raspi per monitor, and a single master pi to control the whole shebang.

As long as you have a few displays with an HDMI input, it’s easy to turn them into a giant monitor. Just plug one Pi per monitor into a network switch, have a Pi (or other Linux box) transmit a video to all the video tiles, and sit back and enjoy the show.

Right now there is an installation guide for creating a Pi Wall, but there are a few limitations; this software only works with the video player provided with the Raspberry Pi, omxplayer. If you’re looking to create an enormous display for a flight simulator or what have you, you might need to do a bit of tinkering under the hood.

Turning A Raspi Into AdBlock

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There’s nothing quite as annoying as seeing bandwidth wasted on unimpressive flash animations, irrelevant ads, and animated GIFs. The bad news is these ads are the sole source of income for a lot of your favorite websites – Hackaday included. The good news is you can turn these ads off with a Raspberry Pi, a WiFi adapter, and a little bit of fun in the terminal.

This build creates a wireless access point with a WiFi adapter plugged in to a Raspberry Pi. With an Ethernet cable plugged in, this effectively turns the Raspi into a wireless router.

To configure the software to block ads, it’s a simple matter of installing dnsmasq from the command line and making sure all the ads on your favorite webpages time out. This means a fairly big hit on the performance of your new DIY router, but with the installation of Pixelserv you can host a 1-pixel transparent GIF image that replaces all the ads and renders them invisible.

It’s a great project if you don’t like watching ads on your PS3, XBox, tablet, or other non-PC Internetting device. If people stealing your wireless connection is a problem, it shouldn’t be hard to make every image upside down or blurry for those rogue WiFi pirates.

Hackaday Links: September 8, 2013

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“I’m sorry Dave, I’m afraid I can’t open the dorm room door.” Does your dorm room have a peephole? Take [pjensen’s] lead and turn it into a mini HAL 9000 using a red LED.

Mix a little work in with your hobby skills. [Vittore] needed to build a video looper to drive some TV screens for a Hotel contract job. He grabbed a Raspberry Pi and got to work. The final product (translated) even uses a shared folder on the hotel’s network as the source slides.

We’re not sure if anyone noticed last Monday (it was Labor Day in the U.S.).  We had a little fun with coffee themed posts. [Tom] wrote in to remind us about the HTCPCP: Hyper Text Coffee Pot Control Protocol. If you don’t have time to read it all, he suggests you don’t miss his favorite, error code 418.

Maybe funny reading isn’t your thing right now, but we have some more helpful stuff to offer. Check out [John Chandler’s] Commandments for using PIC microcontrollers from a few years back.

[Andy] has some old smart phones which he is using in his projects. His beef with the touchscreens is that there’s no tactile feedback. Since these are going to be dedicated displays he’s outlining the touch controls with tape to let your finger know what it’s doing.

If you’re living in your first home in America there’s a really good chance it’s a 1950’s ranch house considering how many of them were built after World War II. Bring its infrastructure into the information age with a cable retrofit. [Andrew Rossignol] just did so and posted a lot of pictures of the process.

If you liked [Ken Shirriff’s] post about the Sinclair Scientific Calculator we think you’ll love his continuation of a Z80 reverse engineering series.

Spoofing WiFi AP Based Geolocation

[Pierre Dandumont] just finished up a little project that will give Google Maps’ location feature a run for its money. It’s a technique that spoofs WiFi networks in order to relocate the positional data reported via WiFi networks.

He starts with an explanation of the different ways modern devices acquire location data. GPS is the obvious, and mobile network triangulation is pretty well know. But using WiFi networks may be a new trick for you. We’re not 100% certain but we think Google is able to look up location data based on known IP addresses for WiFi access points (this would be a good comments discussion). To trick the system all you have to do is feed some captured AP data into the computer before Google Maps tried to lock onto a location. The video after the break shows Maps with the legit location displayed. After running a quick script whose output is shown above the map position is changed to the spoofed location.

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Put In Pocket Change, Get Bitcoins

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[gbg] put together a neat little project to get people familiarized with Bitcoins. A lot of techies know what Bitcoins are, but the impetus to download the Bitcoin client and start mining is a bit too much for some. [gbg] has a solution for this – a Bitcoin vending machine. Just dump your pocket change in the coin slot, and out comes a QR code that allows you to add Bitcoins to your wallet.

Inside this Bitcoin briefcase is a Raspberry Pi that connects to a local WiFi connection. Every five seconds, the Raspi looks at the current conversion rate of USD to Bitcoins. Once coins are deposited into the briefcase, a receipt complete with a scannable QR code is printed on a small thermal printer.

When [gbg] took this to the latest DEFCON, a lot of people were interested in the project and started shoveling change into the machine. So many people were interested that [gbg] and his compatriots are planning on turning this into a proper open-source device, complete with a bill reader and possibly an ASIC miner so the Pi can sell the coins it produces.

Check out the video below for some more info.

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