
Snapdragon Tech Blog
Musings of a systems administrator and open source developer
Here just some upaid advertising for a nice armhf-based XBMC distro, I discovered some time ago. If you just want to use your RPI for watching movies and TV-shows, this is definitely for you. It auto-starts XBMC, mounts USB-drives and lets you connect to NFS and SMB as well. They only thing you might want to do is keep your XMBC-user folder on a different drive, so you can easily switch versions and always have a backup.
I wrote about doing CCTV with zoneminder before, but realized that this might be overkill for many people. If you use less than 4 cameras, you can use the motion package. It works nicely with the Logitech webcam, I connected to my Raspberry.Figure 1: Raspberry Pi running motion over a web browser.The camera worked out of the box except that saturation, brightness, etc was way off. You can configure it with the_ v4l2-utils_ package. Once you have verified that the picture is OK by using _uvccapture_, you should be ready to install _motion_. For my USB webcam, motion worked out of the box. No settings needed at all. For finetuning, I changed the _framerate_ in /etc/motion/motion.conf to 25. Even at that rate, load stayed at 0.00 with abotu 20% CPU usage. Maybe the GPU is doing the bulk of the image processing work.
The outdated and little-used calDAV and cardDAV service at cal.snapdragon.cc:8443 has been discontinued in favor of the more modern ownCloud. Users are encouraged to move their data to the new platform. The OTA-profiles are already adapted to the new service. The service will probably be turned off on 1 Nov 2012 or after ownCloud gets better calendar sharing.
Note: zoneminder might be overkill for many people. If you have less than 4 cameras, also read my article about doing CCTV with the motion package.
One of the first uses, for the Raspberry Pi, I thought of was qick-and-dirty CCTV. This could be useful for scenarios, like remote construction sites, senior citizens, holiday homes, etc.
The only gear needed is a Raspberry Pi, a USB webcam and internet access through a router. The webcam could also be a network camera or a network digitizer. That way you have more flexibility with your location. The router could be substituted for a 3G data stick. If you have a spare TV, you could also use it for viewing those cameras.
The other day I set up Ubuntu in a virtual Machine to do some preparation work before deploying a similar setup in Amazon’s EC2. This basically included programming some Java in Eclipse. When I had to show some stuff to a colleage, I found a quick trick to share a screen remotely on Lifehacker.
This also works well, if you don’t have a screen for your Raspberry or want to access some work files, while on the road. First you need to install the necessary packages
Yesterday, I described how you can use your Raspberry Pi to download and access torrents. Today my parents asked me to help them set up printing via their iPads. They have a rather old HP Deskjet 5940 printer with a simple USB interface.
First you need to install CUPS (common unix printing system) for printer access. In my case the required printer drivers were installed automatically (hplip). If you are using a different printer you might have to check which packages you need.
The raspberry pi is a surprisingly powerful and cost-efficient computing device. Yesterday I put together this simple setup script to turn your new raspberry into a mean green downloading machine. The only requirement is an existing internet router and a working raspberry with SD-card.
Update July 2013: Here is another image for headless installations, only 220 MB big.
The guys on the official raspberry site have some nice images for downloading, but since we won’t be using the graphical UI, we can use a the slim image put together by darkbasic on his site linuxsystems.it. Just follow his instructions to download, extract and install the image to a compatible SD-card. A list of tested and compatible SD-cards is available from the official site.
While installing make sure to enable SSH-access by renaming the boot-enable-ssh.rc boot.rc
Once your raspberry has booted, you need to find out its IP by looking at the router’s DHCP table. Just look for a device name raspberry-pi.
Next just create a new text file by typing vi setup.sh in your terminal window while logged into the RP. Then just copy the script provided with this blog post to your clipboard. Press “i” to go into editing mode and paste the script with Ctrl/Cmd+v. Then save it with ESC, : x. Execute the script by issuing sh setup.sh. As opposed to the default Debian image, the darkbasic image gives you root access by default. When using another image, execute the script with sudo sh setup.sh.
With a majority of households using wireless access points (AP) for internet, secure Wifi has become a key consideration in people’s digital lifes. The outdated encryption standard WEP, which is rarely used any more can be broken in less than 10 minutes. For the newer WPA no direct attack exists so far. The only way is to try a large number of passwords.
Recent advances in parallel computing and graphic cards (GPU) have drastically shifted the odds in favour of potential attackers.
On Sunday all connection data for telephone and internet connections will be saved for 6 months. This might sound harmless and people will say that they don’t mind, because they have “nothing to hide”. No matter what, once this infrastructure is in place, it can be used for all kinds of things and should therefor be opposed from the start. Consider this: Before contacting someone, you need to think, whether you want this person to be associated with you or not (because this information will be saved).
On many occasions, you might want to resize a PDF to send it by Email or put it on the web. There are many useless Share- and Bloatware-tools (like Adobe Acrobat) that might or might not help you with that.
If you happen to work on a Linux, BSD or Mac OSX machine, you can simply use ghostscript for the task. It’s much faster and gets better filesizes than the Optimize-function of Adobe Acrobat.