Raspberry Pi Learns The Lost Art Of Teletext

July 7, 2013 by 35 Comments

rpi-teletext

Exploring dead protocols is often the calling card of hobby electronics enthusiasts. And why not? The mistakes have already been made and fixed — you can learn from them. This Raspberry Pi TeleText hack is the perfect example. It let [Moonlit] explore the realm of generating composite video, as well as establishing communications between the Raspberry Pi  and a microcontroller.

Teletext was a method of accessing information on a television before computer networks were available to the general public. It was pretty impressive at the time, as you can tell from this Retrotechtacular feature. [Moonlit] started looking into recreating a Teletext device by simply generating a PAL signal with an AVR chip. He was met with an equipment failure (remember, it’s always a hardware problem) in to form of a fake composite to USB dongle. After changing the receiving device he was up and running and ready to explore the particulars of the protocol. As you can see, his success even led him to spin a breakout board which plugs in to the RPi GPIO header. A Y-splitter (joiner?) combines the composite output of the RPi with the the overlay data from his own board.

3D Printed Bike Shifter

July 7, 2013 by 26 Comments

Shifter

[Rich] is embarking on a fairly long bike trip in a few weeks – Seattle to Portland – and thought including some 3D printed gear on his ride would be a fun endeavor. His first idea was a printed belt drive, but the more he looked at that idea the less realistic it seemed. He finally hit upon the idea of creating a 3D printed bike shifter, and after an afternoon of engineering and printing, the shifter ended up working very well.

[Rich]’s shifter is actually a friction shifter. Instead of ‘clicking’ into position, this type moves the derailleur gradually. It’s much more tolerant of slight misalignment, and most touring bikes – the type that would embark on long journeys along the coast of the Pacific northwest – have these types of shifters.

Total printing time was about one and a half hours, and was attached to [Rich]’s bike with off-the-shelf hardware. He’s already put about 150 miles on his custom designed shifter with no signs of failure.

Putting Two Years Into One Bowl

July 7, 2013 by 4 Comments

bowl

 

Over the last few months, [Frank Howarth] has been putting a lot of effort into a gigantic sequoia log he started milling two years ago. He recently completed a wonderful chair, but in the years these gigantic blocks of lumber have been sitting around, he’s always had one project in the back of his mind: a giant wooden bowl made from this sequoia log.

The wood for this bowl came from a relatively small cutoff from the original sequoia log. [Frank] had initially cut this cutoff into a circle to let it dry for an eventual run on a lathe. The bowl blank was so big, though, that he needed to create a jig to trim off most of the excess and keep from wasting many hours with a gouge.

With a bowl this large – about 20 inches across – simply screwing it onto the lathe wasn’t an option. [Frank] had to construct a jig for his chuck, capable of holding the bowl by the rim so he could shape the bottom.

The end product, coated with linseed oil and beeswax, is a work of art. Making anything this size on a lathe takes a lot of skill, and we’re thankful for [Frank] sharing it with us.

Brute Force Attack Xbox 360 Parental Controls

July 6, 2013 by 11 Comments

brute-force-xbox-360-parental-controls

The Xbox 360 has the option of parental controls. It limits the rating of games which can be played on the system. [Oscar] didn’t really need to remove the lock-out. It was simply an interesting proof of concept for him. In the image above he’s holding up a Vinciduino board. It has an ATmega32u4 chip that can brute-force attack the Xbox 360 parental code (translated).

We’ve seen quite a few of these attacks lately. Like the recent iPad pin attack this uses the microcontroller to emulate a keyboard. As you can see in the video, [Oscar] first navigates the menu system to the unlock code screen, then plugs in his device.

The unlock screen calls for a four-digit numeric PIN. That’s a total of 10000 possible combinations. It looks pretty slow in the demo, but according to his calculations the worst case scenario would still break the code in less than seventeen hours. Apparently there’s no lock-out for the max number of wrong codes.

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Bolstering Raspberry Pi HDMI With A Current Regulator

July 6, 2013 by 18 Comments

rpi-hdmi-current-regulator

We’ve never tried using an HDMI to VGA converter with Raspberry Pi. We heard they were expensive and have always just used HDMI out (although DVI would be just as easy). Apparently if you have a VGA converter that isn’t powered the RPi board may output unstable video due to lack of current from the connector. [Orlando Cosimo] shows how to fix the problem with a few inexpensive components.

Just this morning we saw a portable PSU using an LM317. This project uses the same part, but in a different way. [Orlando] uses three resistors in parallel to make the LM317 behave like a current regulator (as opposed to a voltage regulator) which will output about 550 milliamps. Input voltage is pulled directly from the 5V line of the microUSB port. The output is injected into the HDMI connector. This will boost the amount of juice available to the unpowered VGA converter, stabilizing the system.

There are a lot of other power hacks out there for the RPi. One of our favorites is pulling the stock linear regulator in favor of a switch mode regulator.

[via Dangerous Prototypes]

Pull-out Pantry Fills Space Next To Refrigerator

July 6, 2013 by 24 Comments

pull-out-pantry

 

Your refrigerator needs a few inches of space on the hinge side in order for the door to open fully. If there’s a wall on that side it means you leave a gap. A bit of lumber and some inexpensive hardware can turn that gap into a pull-out pantry.

This picture is from [Ratmax00’s] pantry project. He had a 6.5″ gap to work with and started the build by making a wooden frame using pocket screws for the butt joints. Four casters were added to the bottom to make it roll in and out easily. He needed a handle and a way to make sure commodities didn’t fall off the shelves. He chose to use a 3D printer for brackets that hold the fence dowels and a custom handle. If you don’t have that just hit the cabinet hardware aisle at your local home store.

We wonder if it would have been possible to use full-extension draw rails mounted above and below the cabinet in addition to a couple of wheels? This would help keep the pantry from scraping against the fridge or the wall.

While you’re building bookshelf sized things why not get to work on a hidden door as well?

Turning A Router Into An Arduino Shield

July 6, 2013 by 15 Comments

[Dirk] had a problem: while he already had an Arduino with an Ethernet shield, he needed WiFi for an upcoming project. Running a Cat5 cable was out of the question, and a true Arduino WiFi shield is outrageously expensive. He did, however, have a WiFi router lying around, and decided it would make a perfect WiFi shield with just a little bit of cutting.

The router [Dirk] used was a TL-WR702N, a common router found in the parts bins of makers the world over. Inspiringly, the size of the router’s PCB was just larger than the space between the Arduino’s pin headers. Turning the router into a shield is simply a matter of scoring the edge of the board and gluing on a few pins for mechanical strength.

Power and ground lines were soldered between the pin headers and the router, while data is passed to the Arduino and Ethernet shield through a short cable. It may not look pretty, but if it works in a pinch we can’t complain.