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Archive for August, 2012

Raspberry Pi Operating Systems

August 27, 2012 3 comments

‘Tux’, the Linux mascot

There is a choice of operating systems for the Raspberry Pi, most of which are variants of Linux. Apparently there is work being done to make the Android OS and other operating systems available for the Pi, however these aren’t yet complete.

The operating system you choose to install will depend on how you intend to use your Pi. I wanted to be able to access Youtube from my Pi, but the recommended Debian based operating system doesn’t support Flash, so I had to look for an alternative. I found RaspBMC which is a version of Linux with a media centre add-on called XBMC, which allows access to music, video and image files. However, the media centre limits the functionality and I couldn’t figure out how to browse the web or do any non-media centre activities with RaspBMC.

In the end I got two SD memory cards, one with RaspBMC installed and one with Debian ‘wheezy’. If I want to watch videos or listen to music I boot up with the SD card containing RaspBMC, and if I want to do web surfing, e-mail, programming and productivity tasks, then I use the SD card with Debian ‘wheezy’. It’s not an ideal situation, but since Linux is open source and constantly being updated I’m sure someone will come up with something better.

Installing RaspBMC

I downloaded the Windows installer from the Download section of the RaspBMC site, inserted a SD card into my computer and ran the installer. It was that simple. However, when I booted the Pi I got a string of networking errors and it ended up at a command prompt instead of booting into the Graphical User Interface. I later found out that you MUST connect the Pi to the Internet for first install, as it connects to the Internet and updates automatically. I wish this had been explicit in the instructions.

After installing I had to install Add-ons to use various features such as Youtube. Installing the add-on for Youtube was simple – all you do is choose it from a list and it installs automatically.

I had heard there was a BBC iPlayer add-on, however it wasn’t listed in the Add-Ons, and I still haven’t been able to find out how to install it or even where to get it.

RaspBMC worked fairly well, but was a bit sluggish. When I used with with an underpowered power supply (5 volts, 0.4 amps) I found that the mouse pointer disappeared occasionally and the Pi crashed a lot. This was fixed by using a 5 volt 1 amp power supply.

Also, when running the Youtube Add-on when connected to a TV with the RCA connector I found that the video signal turned into static and I had to reboot the Pi. I never successfully got a video to play when connected to a TV with the RCA. However the HDMI connector worked perfectly. I have since read that an update to RaspBMC may have resolved this video problem, but I have yet to try it.

One big drawback of using RaspBMC seems to be the inability to do anything outwith the ‘media centre’ – so it’s not easy to use office applications or a web browser. Perhaps it is, but I just haven’t found how to yet.

Installing Debian ‘wheezy’

Installing the ‘recommended’ Debian Linux was fairly simple too, but not as easy as RaspBMC. First I had to download a disk imager (Win32DiskImager) and the zip file containing the disk image. The SD card was inserted into the computer and after running the disk imager I selected the disk image and the appropriate drive. The files copied over and I was able to boot up the Pi with ‘Debian Wheezy’.

During first boot-up I was prompted for information such as the time zone, etc and whether I wanted it to start the GUI automatically. If you don’t start the GUI automatically the Pi boots to a command prompt and you can enter startx to start the GUI.

The GUI itself, called LDXE looks very much like Windows and most people will be able to navigate their way around and start applications.

The web browser that is provided is called Midori, and I found it to be quite slow and not capable of viewing some complex sites containing HTML5 or Flash content.

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Recipes for Raspberry Pi

August 13, 2012 3 comments

Raspberry Pi computer

This series of blogposts is intended as a beginners’ introduction to the Raspberry Pi computer.

Raspberry Pi is a credit card sized computer that plugs into a TV set and a keyboard. It is intended as an inexpensive way to allow children to learn about computing and programming. The computers themselves cost around £30, but you will also need a few peripherals to get started, including a keyboard and mouse, TV set, power supply and a SD memory card.

I bought my Raspberry Pi from Farnell/Element 14. It cost just under £30. Due to demand, the mini-computers were in short supply and it took about 2 months for me to receive it after ordering.

I bought a Raspberry Pi for a couple of reasons, first to get a low cost computer that my kids could use for accessing the Internet for their homework, and secondly out of interest in the technology and its uses.

The Pi comes without any additional peripherals or software. The operating system has to be downloaded from the Internet using another computer and loaded onto a compatible SD memory card.

Peripherals

  1. USB keyboard – £5 (Asda)
  2. USB mouse – £3 (Asda)
  3. Power supply with Micro USB connector 5V, 1000mA – £7 (Tiger)
  4. TV set with HDMI connector – £130 (Tesco)
  5. HDMI cable – £1 (Poundland)
  6. SD memory card – £12 (Asda)

It is important that a suitable power supply is used with the Raspberry Pi. A 5 volt 1 amp unit is recommended. I tried a unit that only provided 400 milliamps instead of 1 amp and I found that the mouse didn’t always work and the Pi was prone to crashing.

Having read a few posts on the Raspberry Pi forums I found that several people had experienced compatibility problems with certain high speed SD memory cards. I bought a Sandisk SDHC 8 GB (Class 4) which some people recommended and it has worked without problem. I’ve also tried a 4GB version of the same card, again without problem.

The Pi connects to a monitor or TV with a HDMI connector. You can buy a cheap 1 metre  HDMI cable in Poundland. There is also a RCA video output which can be connected to older TV sets and some projectors, however I had some issues with this that I’ll explain in a later post.

The Pi comes as a bare circuit board with no cover, but several are available from different online suppliers ranging from around £5 – £15. As a temporary measure I made a Raspberry Pi case from Lego using some diagrams I found online.

There is a choice of operating systems for the Raspberry Pi, all variants of the open-source operating system called Linux. The operating system can be downloaded and installed on the SD memory card, or it is also possible to buy a memory card with the operating system preinstalled from some suppliers. The recommended operating system is a variant of Debian Linux and is downloaded from the official Raspberry Pi site, but other versions can also be installed depending on what you want to do with your Pi. For example RaspBMC turns a Pi into a media centre that can be used for playing videos and music and for accessing Youtube.

Installing the operating system didn’t prove very easy at first – there are several steps to follow, and the instructions aren’t always clear. This will be the subject of my next post on the Raspberry Pi.

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