Multiple Raspberry Pi Boards Used To Create Video Wall

July 22, 2013 by Mike Szczys 51 Comments

Five Rasberry Pi’s are used to drive this four-display video wall. This screenshot shows the system playing back some BBC documentaries. The sync, alignment, and video quality all seem to be spot on which makes it quite easy for your eye to assemble the images into one picture.

Each screen has its own Raspberry Pi which generates the HDMI video shown on the screen. These are fed from one central RPi board which acts as the controller. Video is pushed between the boards using the Real Time Streaming Protocol (RTSP) available through the Linux GStreamer package. Synchronization between the different video boards is taken care of using network time. [Samer] mentions that this system is scalable — each additional screen simply requires one more RPi to drive it.

The team also did some experiments with live video. They added a sixth RPi board with the camera module in order to display a live feed.

Computer Monitor Ambilight Clone Shows Remarkable Performance

July 13, 2013 by Mike Szczys 54 Comments

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Check out this fantastic Ambilight clone for a computer monitor which [Brafilus] has been working on for a few years. It’s actually the third revision and watching the demo video below left our jaws agape.

Details are only available as comments on the YouTube page. But he’s given us just enough to be satisfied. His self-etched board hosts a PIC 18F14K50 microcontroller. It is talking to each of the 28 LED pixels which themselves live on tiny hunks of diy PCB as well. He wrote his own PC software in C# to capture the colors around the edges of the screen. He also worked hard to ensure there are plenty of tweaks available for true color matching between the monitor and what your eye sees bouncing off of the wall.

If you’re looking for something like this on your television set go back a couple of days and check out that standalone unit.

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A Very Small HDMI Display

July 8, 2013 by Brian Benchoff 26 Comments

With dozens of pocket-sized ARM boards with HDMI popping up, we’re surprised we haven’t seen this before. [Elias] made a custom driver board that takes an HDMI input and displays it on a very tiny, high-resolution display from a cell phone.

The display used is the same as what comes stock in the HTC desire HD. With a resolution of 800×480, it’s more than enough for a basic desktop, and while it’s not a 1080p monster from a few flagship phones, it’s more than enough for most uses.

[Elias]’ board consists of a Himax display driver and a TI DVI receiver. Included on the board is an MSP430 microcontroller used for initializing the driver and display. This build was originally intended for the Replicape, a 3D printer driver board for the Beaglebone, but because the only connections to this board are HDMI and an SPI to the ‘430, this also works with the Raspberry Pi.

Raspberry Pi Learns The Lost Art Of Teletext

July 7, 2013 by Mike Szczys 35 Comments

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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.

MacBook Pro Retina Display With A Normal Computer

July 5, 2013 by Brian Benchoff 30 Comments

If you’ve seen one of the fancy, expensive MacBook Pro laptops with a Retina display, you’ll know how awesome having that much resolution actually is. This incredible resolution comes with a price, though: the MBP with a Retina display is about $500 more expensive than the normal resolution MPB model, and it’s very difficult to find a laptop of comparable resolution without cries of fanboyism being heard.

[Daniel] over at Rozsnyo came up with a neat solution that connects one of these fancy 15-inch Retina displays to just about any computer. The build is the beginning of a product that works just like the previous DisplayPort adapter for the iPad retina display, but with the possibility of a few added features such as HDMI input and use of the internal webcam and WiFi antennas.

This build isn’t really a finished product anyone can buy and plug into a replacement Retina display just yet. Even if it were, it’s extraordinarily difficult to find a replacement display for the high-end MacBook for under the price of a really good monitor, anyway. In a few years, though, when the old, busted Retina laptops are traded up for a new, shiny model, though, we’ll be the first to try out this mod and get some serious desktop space.

Modifying A CRT Television For Use As An Arcade Monitor

June 17, 2013 by Mike Szczys 29 Comments

Finding himself in need of an arcade monitor [Eric Wright] turned to this ancient CRT television. The problem is that arcade monitors and televisions didn’t operate in the same way, differing in both resolution and refresh rate. [Eric] modified the television to work like an arcade monitor, but only with limited success. He’s hoping a few more alterations will lead him to a complete solution.

The image above shows him testing a Pac-Man machine on the altered Sharp television. Those familiar with the game will immediately notice that there is something wrong. We see most of the tracks upon which Pac-Man and the ghosts travel, but he maze itself is completely missing. To get to this point [Eric] consulted the television and arcade schematics to figure out how to connect the composite sync and three color channels directly to the arcade machine. This way the CRT timing is forced to conform to the game standard. The problem is that there is no way to adjust the drive and cutoff of the individual color channels. This is something [Eric] hopes to fix in the next iteration of his experiments.

If you already have a working arcade monitor but no gaming cabinet why not use a Raspberry Pi?

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Update: Live Video Played On LED Strip Display

May 26, 2013 by Mike Szczys 11 Comments

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[Paul] took this LED display along with him to Maker Faire. To give it some interactivity he figured out a way to make it play live video. It is also activated using some stomp actuators built from piezo speaker elements and rubber floor mats.

This moves his original project in new directions. Back in February he was showing off the RGB LED strip display. He had it playing video but that was all dependent on using previously processed files. This upgrade uses a BeagleBone Black (the newest rendition of the ARM-based development board). [Paul] had tried using a Raspberry Pi board but had trouble with the webcam (mounted above the LED display) dropping frames. With the new board he is able to use the Video4Linux API to capture 30 frames per second and push them out to the display.

So far he’s had five out of the 1920 LEDs die on him. This shows off a couple of good things about using strips like this. A dead pixel doesn’t affect its neighbors. And replacement is as easy as cutting the ribbon on either side of the bad component, then soldering a new segment in place.