Using OpenCV With The Raspberry Pi

March 4, 2013 by Brian Benchoff 47 Comments

When we first heard of the Raspberry Pi we were elated that projects that once required a full-blown computer could now be done on a tiny, and cheap board running Linux. Unfortunately, we haven’t seen much in the way of using computer vision algorithms on the Raspi, but thanks to [Lentin] the world of OpenCV is now accessable to Raspberry Pi users everywhere.

[Lentin] didn’t feel like installing OpenCV from its source, a process that takes the better part of a day. Instead, he installed it using the synaptic package manager. After connecting a webcam, [Lentin] ssh’d into his Raspi and installed a face detection example script that comes with OpenCV.

It should be noted that [Lentin]’s install of OpenCV isn’t exactly fast, but for a lot of projects being able to update a face tracker five times a second is more than enough. Once the Raspberry Pi camera module is released the speed of face detection on a Raspi should increase dramatically, though, leading to even more useful computer vision builds with the Raspberry Pi.

Building A Touchscreen XBMC Setup With The Raspberry Pi

March 2, 2013 by Mike Szczys 29 Comments

[Andrei Istodorescu] has been hard at work building a 7″ touch-screen rig which runs XBMC. It may be upside-down, but the Raspberry Pi board which is front and center is still easily recognizable. There’s a lot of stuff connected to it in order to pull this off, and even more software configuration. But as you can see in the clip after the break he did get it working!

The screen is an eGalaxy 7″ touch sensitive module he picked up on eBay. It sounds like it was meant for a backup camera in the dashboard of a car. He compiled his own Linux kernel to add support for the screen. It uses HDMI for the video interface with the driver board, and the touchscreen connects to one of the USB ports. The rest of the setup involves compiling XBMC with touchscreen support and calibrating the screen to accurately sense input.

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Optical Data Transfer Project At Local School’s Family Science Night

February 28, 2013 by Mike Szczys 9 Comments

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[Dave] wanted to show off a project at his 4th-grade son’s school during their family science night. We haven’t heard of an event like this before but it sounds like a fabulous idea! He had a new laser he wanted to include in the project, and noticed that his son was learning about how ASCII maps letters to binary number when the idea struck. He ended up building an optical data transfer system that demonstrates binary code.

This presents a fantastic learning opportunity as the project invited the school kids to select encoded strips like the ones seen above to form a secret message. The laser is pointed at a photosensor which is being read by a Raspberry Pi board. The Python code looks for a baseline and then records increases and decreases in intensity. Since the translucent tokens have either holes or black lines for 0 and 1 the baseline approach does away with the need to clock in the data. [Dave] reports that everyone who tried out the experiment was fully engaged at the prospect of pushing pieces of tape through the sensor and watching their secret message appear on a monitor.

He was motivated to write about this project after reading about data transfer using an LCD screen and photosensor.

Multibooting The Raspberry Pi

February 24, 2013 by Brian Benchoff 28 Comments

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Those of us have been dual booting Linux, Windows, and OS X operating systems for a while will be familiar with bootloaders such as GRUB and its ilk. Surprisingly, though, we haven’t seen a bootloader for the most popular computer of the last year – the Raspberry Pi. It makes sense to have a bootloader for the Raspberry Pi; with dozens of different distributions from Raspbian, Occidentalis, and a bunch of more esoteric distros, we’re surprised we’re only just now seeing a proper bootloader for the Raspi.

Berryboot is extremely simple to install – just copy it onto a FAT formatted SD card and you can install multiple OSes on your Raspberry Pi. On booting, Berryboot shows a dialog box of all the installed operating systems, with new ones able to be installed over the internet from a Berryboot menu.

You can grab Berryboot over on the gits. Berryboot also works with those Allwinner A10 single board computers, but the Hackaday tip line hasn’t seen hide nor hair of those boards.

Retro Gaming Just In-case

February 21, 2013 by Mike Szczys 12 Comments

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You can look and look, but you won’t find a Super Nintendo inside of this retro gaming rig. [Webrow] is giving his vintage hardware a rest, and taking this all-in-one game emulator suitcase wherever he goes.

The machine at the heart of his build is of course a Raspberry Pi. You really can’t beat the ubiquitous board for cost, power, and hardware extensibility. An LCD panel from a broken laptop comes along for the ride having been mounted in the lid. For a long time there was no hope for reusing these panels, but [Webrow] found an adapter board (for nearly the same price as the RPi) which converts the DVI from the Pi to the LVDS needed by the screen. The connections and mounting scheme for the screen were where most of the project work was done. Connecting the controllers simply involved soldering some SNES controller sockets to an RPi breakout connector. We do have to compliment him on the red bezel which hides all of the power cords and other unsightly bits. The case look sturdy and ready to play!

Playing With The Minecraft API And A Raspberry Pi

February 16, 2013 by Brian Benchoff 8 Comments

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It hasn’t been a week since Minecraft for the Raspberry Pi has been released, and already we’re seeing some cool builds that bridge our analog world with Minecraft voxel land. [Martin] got his hands on the Raspi version of Minecraft and decided to take advantage of the API Mojang threw into the build by making a huge analog block clock that keeps real world time in the Minecraft universe.

Basically, [Martin] created a small Python script that draws the face and hands of a clock in a Minecraft world. The Minecraft API comes with neat functions such as drawCircle, and drawLine, so making a real clock face is as simple as getting the system time and doing a bit of trig.

After the break you can check out [Martin]’s Minecraft clock in action. If you’re running the Pi version of Minecraft, you can also get this running on your machine with the code on [Martin]’s git.

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Raspberry Pi As A Plug-in Hash Harvester

February 14, 2013 by Mike Szczys 15 Comments

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Plug in the power and Ethernet and this Raspberry Pi board will automatically collect Windows hashes from computers on the network. With a couple of RPi boards on hand [Travis] was searching for more hacks to try with them. This made a great little test to see how the board performs with the well established attack.

To start he booted into the standard Raspbian distribution. From there he loads the Metasploit framework which brings most of the necessary tools into play. It uses the Web Proxy Auto-Discovery Protocol (WPAD) to request hashes from any Windows machines listening on the network. Some version of the OS respond with LM hashes, others don’t. The importance of this and the particulars of using rainbow tables to crack the hashes is explained in this article on the subject.

We wouldn’t mind having a little hardware hack that adds a couple of LEDs to the GPIO header so you know when the RPi is done collecting the data.