Product review – A Slice of Pi

1. Introduction:

This nice little breakout board initially seemed like it might not be worth a post but it has been one of the most useful, versatile and helpful bit’s of kit in my “Pi maker box” and comes with the added benefit of being very well made as well as extremely reasonably priced.


2. A closer look:

The whole thing comes as a “solder at home” kit but if you’ve ever seen a soldering iron up close you should be ok as assembly is limited to soldering the headers in place.

The layout is very convenient and after assembly the following is broken out and easily accessible:

  • 8pin header row for the SPI and I2C pins (2.54mm pitch)
  • 8pin header row for the Raspberry PI’s 8 general purpose I/O pins (2.54mm pitch)
  • Solder pads for 3v3, 5v0, GND, RX & TX
  • XBee style connector for XRF / XBee / RN-XV / XBT / RF-BEE
  • Small prototyping area



The little shield then get’s connected to the Raspberry Pi’s main pin header. Size matches with the original board which makes it a neat companion in enclosures. The board is propped up by one of the capacitors opposite of the main header row, a little bit of isolating tape on top of said connector or double sided sticky tape I found works very well.



3. Shopping links:

If you’re tempted you can get your “Slice of pi” directly from Ciseco. Cost is very reasonable at £3.90 which includes VAT but excludes shipping.


Various alternative suppliers exist but all appear to be more expensive than Ciseco:



How to run your Raspberry Pi from POE for under £15

1. Introduction:

I am currently setting up a sensor network to monitor and optimise a data centre as my MSc dissertation and hence had a need to run a number of Raspberry Pi powered sensor nodes off POE enabled infrastructure grade switches. Since POE support exists in various forms for Arduino I had made the fatal assumption that this would be available for the Raspberry Pi platform as well or at least be quick to copy from some pain-free cook book. And so I embarked on the exciting challenge to source POE support for my Pi nodes with manufactured parts behind a scalable supply chain only (<- no soldering is what I mean) and for a target price of under £15.


2. The Solution:

Since I had ruled out batteries and 240V wall wart power supplies as a power source for the nodes POE seemed the only feasible way forward. I searched high and low for something that would offer a USB port from POE but without success. Home-brew type POE systems are well described but I have to build this on top of an existing corporate grade POE infrastructure switch layer so addition of home made POE injectors was out of the question. To keep the system scalable and maintainable by staff without knowledge of handling a soldering iron (good luck finding a sysadmin with that skill these days) I had also decided to pick manufactured components with standard connectors only.

First break through came in form of the TP Link POE splitter which I found by pure luck while shopping for a new IP-webcam. This delightful little box converts down from POE 48V to either 5, 9 or 12V (adjustable with a little switch) and, after sucking out the POE supply voltage, passes through the network connection to another port on the other side. Next to the network out port it has a little barrel DC connector with exactly the type of socket found on the Arduino which supplies the chosen 5-12V DC voltage.




So far so good, I had successfully converted down from POE to 5V so I set out to find some adapters on Amazon. Once I had identified the type of barrel I was working with (the Arduino documentation gave it away as a 2.1mm) it wasn’t too hard to find an adapter from said 2.1mm barrel to a standard USB plug. As far as I know these sort of adapters are/were used to charge older mobile phones off a USB port.



Almost there, just needed to get down to micro USB which is the type of socket used for the power socket on the Raspberry Pi. Guess this stage would already have been sufficient to run the Pi by simply plugging this USB plug into one of the Pi’s USB sockets but I usually try to keep those free to hook up a USB keyboard and mouse in emergencies. The last missing link in form of a USB to micro USB adapter was easy to find. Biggest challenge was to find a nice one that would not come from Hong Kong for £9.50 shipping each…



Right then, all together this is what the result looks like. I’ve successfully tested this today with a recent Pi model :)

2013-06-13 16.49.18



3. Shopping list of links for what I bought to get the above:

TP LINK PoE Splitter – TL-POE10R
Link to manufacturer websiteLink to Dabs

£10.60 each

StarTech 3 feet USB to Type M Barrel 5V DC Power Cable
Link to Amazon
£2.70 each

USB 2.0 A female to Micro USB B male Adapter Cable
Link to Amazon
£1.50 each

Unless I’m mistaken this adds up to £14.80 for each set and is hence within my envisaged £15 per set budget :)


The SK Pang Raspberry Pi starter pack


I’ve started to build up little prototypes with my Raspberry Pis and since I got used to the prototyping setup I’ve got for my Arduinos which consists of a small plastic board which has an Arduino and a little breadboard mounted on it I set out to find something similar for the Raspberry Pi. Luckily I didn’t have to search far as said contraption is available from SK Pang and they even have it in two different sizes. They currently only sell the smaller version in form of one of their starter kits but the bigger one is available as another starter kit as well as on it’s own. Here are some pictures and links:


Small starter set:


Large starter set:


Large without the extra bits:



What’s in the box:

I tend to be short on space on my desks so I got the smaller version. This is what came with the pack I bought:

  • Two nicely cut bits of acrylic
  • Four plastic stand offs to mount the acrylic part with appropriate distance to fit a RasPi in-between
  • Eight screws to connect the stand offs to the acrylic plates
  • Four little rubber feet to put underneath the base plate
  • A small breadboard
  • 10 male/female jumper wires to connect the Raspberry Pi GPIO pins to the breadboard
  • A bunch of 5mm LEDs (4x red, 4x green, 4x yellow)
  • 12 resistors to run above LEDs
  • Two mini push buttons
  • 2x 10k resistors for circuits with above push buttons




Surprisingly easy I have to say. Screw the bits together, the RasPi sits safely in grooves cut into the stand offs, fit breadboard thanks to sticky back, fit little feet underneath, done!



Final thoughts:

I really like this one for three reasons. First off it’s affordable, second it fits the purpose, third it’s well made. The acrylic parts are carefully cut and had no marks or finger prints. All other parts that come with the set are of good quality as well and everything fits together nicely. Somebody even paid enough attention to ensure the jumper wires are long enough to reach all corners of the breadboard.

The only small downside is that one of the plastic stand offs is a bit close to the SD card slot which makes it a bit harder to insert the card. But then there isn’t really much room on that corner of the board and the stand off had to go somewhere so since it doesn’t really infringe on functionality I’m happy to accept this as a fair compromise :)



The Top 10 Raspberry Pi products for 2012

I’ve been looking around online and I think these are the big things we can expect to see hit the market within the next 6 months. I’ve also added a little section at the end which covers my take on the potential impact of the arising Raspberry Pi ecosystem.


Let’s start with the hardware-ish products:

1. Enclosures, Enclosures, Enclosures…
I could probably have written a post on it’s own about the ten best enclosure drafts I’ve seen, there will be MANY. The only thing currently available are the acrylic sandwich type things without side walls. The obvious reason for not having side walls is that they were produced in a rush without exact RasPi measurements to get to market as quickly as possible. My favourites so far are:
Adafruit Pi Box – Enclosure for Raspberry Pi Computers

Adafruit Pi Box - Enclosure for Raspberry Pi Computers

ModMyPi Raspberry Pi Case

ModMyPi Raspberry Pi Case

SK Pang Electronics Raspberry Pi Cover with Breadboard Area – Clear

SK Pang Electronics Raspberry Pi Cover with Breadboard Area - Clear


2. basic proto board

It’s not too hard to make a basic proto board yourself with headers and perf-board but there are at least two very nice ones I’ve seen that seem worth the investment. The one from Adafruit obviously because it’s very well done and it has everything I could wish for including screw terminals. The Slice of Pi one simply because it’s already got an XBee socket which tends to be harder to fit due to it’s unusual pitch.
Adafruit Prototyping Pi Plate Kit for Raspberry Pi

Adafruit Prototyping Pi Plate Kit for Raspberry Pi

Slice of pi – add on for Raspberry PI

Slice of pi - add on for Raspberry PI


3. Buffered and isolated 3.3V-5V I2C expander shield

I stumbled across this post about adding a MCP23017 I2C expander to a RasPi and SK Pang now sell their starter pack with one of these I2C expanders. Main problem being that all the RasPi GPIO pins are 3.3V and feeding them with 5V will potentially kill the SOC. There are 5V I2C chips out there so anyone who deals a lot with I2C is probably going to look into buffering and converting 3.3V <-> 5V.


4. Buffered and isolated GPIO shield

Same problem with all the other GPIO pins, they connect directly to the SOC and don’t allow to connect a lot of load.
The topping for your Pi

The topping for your Pi

Raspberry Pi I/O Expander Board

Raspberry Pi I/O Expander Board



5. Arduino shield adapter

A lot of potential Pi owners will already be in possession of an Arduino and matching Arduino shields. Even if they don’t have them yet it’s going to take quite a while until RasPi shields get built to provide the same functionality currently available in form of Arduino shields and then the Arduino shields are also already in their XYZ revision with tested code available and bugs ironed out.
Introducing Ponte: Arduino – Raspberry Pi Bridge

Introducing Ponte: Arduino – Raspberry Pi Bridge


6. A high resolution camera

That one was easy to predict, there’s a connector for it on the RasPi :) This will obviously be very popular for all sorts of robotics, automation and surveillance projects.
Camera module – first pictures!

Camera module – first pictures!


7. A touch screen and tested monochrome/colour LCDs

I don’t have any links for this yet but there is a second so far unused connector on the RasPi in form of a DSI connector which allows to talk to RAW LCD panels. Examples of commonly available screens for this will be from Nokia phones or the iPhone with the touchscreen being fed via I2C.
I haven’t seen any RasPi->LCD pictures yet but LCDs should be relatively simple to interface with via UART or posher colour ones via I2C.


I would also expect a ever growing variety of modified “ready-to-go” pre-built images:

8. Highly specialised images
LAMPi – A production ready RasPi based LAMP server

9. Images which conveniently come with software installed for newbies and matching Raspberry Pi user manuals
The Unofficial Raspberry Pi Manual

10. Images which fix bugs and shortcomings of the original debian squeeze image
soft float -> hard float, Raspbian


Evaluation of the potential impact of the arising Raspberry Pi ecosystem:

Let’s do a little mental exercise and have a quick think about an example which combines some of the above with potentially very interesting results:
1. Raspberry Pi Thin Client project
2. A cheap VESA mountable enclosure and later a screen manufacturer who is brave enough to pack the RasPi into the screens case where it can run off the internal psu.

The result would in the best case bee a screen with a SD-card slot and NIC which could only cost £25-30 more than the pure screen but provides a HD capable Linux client or thin client/RDP extender to stream virtual desktops off an internal centralised virtual infrastructure. All students would need to use the machines would be a cheap SD-card and access to an image which works at the specific institution.
And if they change the format of the RasPi to something like a PCMCIA card the screen could have an eject button to swap/upgrade the board :)
Even without being integrated into the screen the above scenario should prove very popular with educational places. They are usually short on cash but the RasPi should be within their financial reach, require little to non maintenance and the main UK RasPi distributors (RS and Farnell) will be on their approved supplier list.
Arduino or Raspberry? Or both?
Personally the biggest difference I see for going from Arduino to Raspberry Pi is the fact that it’s got the processing power the Arduino’s have been lacking so far but still doesn’t suck up crazy amounts of power to still make it a viable solution for physical and pervasive computing projects. Add the fact that it comes with the whole Linux ecosystem including the fact that it allowes all common high level languages access to the GPIO pins and you’ve captured all those who are not familiar with pure C embedded programming. Then add the fact that it can talk to pretty much any screen you might have kicking about and you’ve just drawn in the web designers, creative heads/artists and all those who want to have an impact on crowds.
Hence I expect tons of highly stimulating and exciting projects within the next months once the factories get round to ramping up production numbers and then towards the end of the year finally the first mulit-RasPi projects. I don’t think I’m the only one who could envisage the impact of a Raspberry Pi based parallel computing cluster (Bramble discussion thread) and there’s already a project for a Raspberry Pi based MySQL Cluster which sounds like a great idea for scenarios with lots of little MySQL databases.


Raspberry Pi Project 3 – LAMPi, a Raspberry Pi based LAMP server


LAMPi – The Raspberry Pi LAMP Server Project now also has it’s own website!

Due to the horrible weather last weekend I found more time to play with my Raspberry Pi :)

I’ve got an Arduino/XBee based Wireless Sensor Network with associated storage/reporting back-end and ever since I put it together for a MSc coursework I’ve been planning to swap out the Mini-ITX LAMP server for a RasPi. In the long run I’m hoping to also add one of the XBee Series 2 modules to the RasPi so it can also take on the role of my current XBee-to-Ethernet concentrator (hence the Slice-of-pi boards in step 10). The following is a quick walkthrough of the necessary steps for setting up your own LAMPi and at the end a little section on how to read/write SD-card images, details on my first attempts to do a bit of load testing on the LAMPi with JMeter and further thoughts/links/accessory ramblings.

If you don’t want to set all this up yourself feel free to download my image. It includes everything from Step 1-7 and was created as per Step 8.1. In case you run the JMeter plan from Step 9 against one of these I’d be grateful if you could let me have results and details on your SD-card.

LAMPi a Raspberry Pi based LAMP server


Step 1 – Preparation:

Since there is still a certain amount of “will my XYZ” work with a RasPi I’m going to start by listing what my RasPi is currently connected to. If in doubt buy kit which is mentioned on the official verified peripherals list. I’ve hooked up my prospective LAMP-Pi to:

  • Samsung SyncMaster 226BW with a Belkin HDMI lead and HDMI-to-DVI adapter
  • Cherry wired optical USB mouse, Cherry GENTTIX Model No: JM-03
  • Cherry wired USB UK layout keyboard, Model No: JK-02
  • Apple AC-to-USB adapter and a no-name micro USB lead
  • CAT6 cable to a Netgear 8port gigabit desktop switch
  • Integral 2GB mini SD-card with matching adapter
  • Original Debian Squeeze image

If you are running the Squeeze image for the first time:

  • Your user name is: pi
  • Your password is: raspberry (raspberry is also the password for everything else I’ve installed below)
  • Once you are logged in start LXDE (your desktop) with: startx
  • To get screenshots install scrot and run scrot ‘%Y-%m-%d–%s_$wx$h_scrot.png’ -e ‘mv $f ~/Desktop’
  • If you’re running headless you can reboot via ssh with “sudo reboot” or shutdown with “sudo shutdown -h now”
  • If you don’t like the Midori get Chromium with “sudo apt-get install chromium-browser” and don’t forget to run “sudo chown pi:pi ~/.config” afterwards
  • Most of the below will need root privileges. Start you terminal session with sudo su or add “sudo” in front of the commands.
Step 2 – SSH:

ssh-keygen -t rsa mv /boot/boot_enable_ssh.rc /boot/boot.rc
I’m doing this from OSX so I use ssh username@yourip in a Terminal window. I think on windows you would like to use PuTTY but that’s not my world… ;)


Step 3 – Let’s install Apache 2:

groupadd www-data
usermod -a -G www-data www-data
apt-get update
apt-get install apache2

To test point a remote web browser at http://your-LAMP-Pi-ip. As usual your website’s files will live in /var/www.


Step 4 – Let’s install PHP5:

apt-get install php5
To test put a file called phpinfo.php into /var/www:
cd /var/www
nano phpinfo.php

This is what you want inside your file:

You might also want to install some of these, they all worked on my LAMP-Pi:
apt-get install libapache2-mod-php5 libapache2-mod-perl2 php5 php5-cli php5-common php5-curl php5-dev php5-gd php5-imap php5-ldap php5-mysql php5-odbc

service apache2 restart

To test point a remote web browser at at http://your-LAMP-Pi-ip/phpinfo.php


Step 5 – Let’s install MySQL:

apt-get install mysql-server mysql-client php5-mysql

To test run mysql -uroot -ppassword and replace “password” with whatever you picked when you installed MySQL (but leave the “p” in front of it!) which should get you a MySQL prompt (exit gets you out of that one).


Step 6 – Let’s install phpMyAdmin:

apt-get install libapache2-mod-auth-mysql php5-mysql phpmyadmin

And add the extension to your Apache php.ini with:
nano /etc/php5/apache2/php.ini

add this and save:

To test point a remote web browser at http://your-LAMP-Pi-ip/phpmyadmin


Step 7 - Let’s install TightVNCServer (Optional):

And for all those situations where your LAMP-Pi is running headless but you still want/need a full LXDE desktop I’ve installed TightVNCServer.
apt-get install xorg lxde-core tightvncserver

To start it run: tightvncserver :1
And to kill the above session run: tightvncserver -kill :1

I use Chicken Of the VNC and all I have to do is enter the LAMP-Pi IP into the host box, “1″ into the Display box, put in my password and click connect.


Step 8 – Let’s install creating and writing SD-card images under OSX:

This one isn’t for the faint hearted as it uses dd. If you don’t know what dd is or think it means “disk destroyer” better get yourself a Windows based machine and use Win32DiskImager ( If you’re on Ubuntu I’d recommend a nice graphical tool called ImageWriter (I’ve got Ubuntu on a Sony laptop next to me just for the task of writing images, it’s my fastest SD-card reader/writer :) . Step 8 – creating and writing SD-card images under OSX: This one isn’t for the faint hearted as it uses dd. If you don’t know what dd is or think it means “disk destroyer” better get yourself a Windows based machine and use Win32DiskImager ( If you’re on Ubuntu I’d recommend a nice graphical tool called ImageWriter (I’ve got Ubuntu on a Sony laptop next to me just for the task of writing images, it’s my fastest SD-card reader/writer :) . I’m doing this on OSX 10.7 but it should be very similar on all OSX versions.

8.1 To create an image from a SC-Card:

  • Insert SD-Card (my iMac has a slot at the side underneath it’s optical drive)
  • Wait until your card get’s mounted on the desktop and make a note of it’s name
  • Open Terminal and run mount. You’ll get a list of all your mounted devices and one of the lines should relate to your SD-Card. Mine was called “NO NAME” and I get this back from mount: /dev/disk3s1 on /Volumes/NO NAME (msdos, local, nodev, nosuid, noowners)
  • Take the /dev/XYZ line and strip it back to just the device without the partition. In this case that’s /dev/disk3
  • The following dd command then creates a image called lampi.img in your home directory: dd if=/dev/disk3 of=lampi.img
  • The resulting image will be the size of your SD-card but there’ll be a lot of empty space in your image so it should compress well: gzip lampi.img

8.2 To write back an image to a SC-Card:

  • Insert your target SD-card and wait until it get’s mounted to the desktop
  • Unmount the SD-card with: diskutil unmount disk3s1
  • To write the image to the SD-card with dd run: sudo dd if=lampi.img of=/dev/disk3

Step 9 – LAMP-Pi load testing with JMeter:

I’ve only done a very basic test against /phpinfo.php but, keeping in mind the size of the board and it’s power consumption, the results are impressive. It should serve very well for small/mid sized LAMP projects and with basic html content Apache2 should stand up even against higher visitor numbers. The same test runs with very much the same results in regards to speed from both an ancient 2GB Mini-SD-card and a fast 8GB SanDisk Ultra (15 MB/s, 4) but I will try again once I get my new faster SD-cards. Performance of the MySQL database will obviously be limited due to it running off the same SD-card as the whole underlying system but it will still work well as a storage backend. I’m going to write a JMeter test plan for the MySQL side later today and swap the board in as the storage/reporting back-end for my Arduino/XBee WSN to get an idea how it perfoms under real life conditions.

This is my test JMeter Test plan. All you need to do to use it is to change the IP under “HTTP Request Defaults”.


LAMPi JMeter load testing


Step 10 – Further thoughts, links and accessory rambling:

This project looks very interesting: Raspberry Pi Thin Client project And once they release a final version I’ll try to base my further images on Raspbian rather than the original Squeeze image simply because it’s based on Wheezy rather than Squeeze and has hard float instead of the soft float cheat in the original Squeeze image.

The RasPi seems picky with USB hubs, I’ve got a few cheap ones and it did not like them too much (WG111v2 fails to work as described in the RasPi forum) so I’ve got two Belkin powered port ones on order which are supposedly fixing this issue. Although not on the official “tested hardware”-list my mouse and keyboard are working ok so far but I’ve got a Apple wired keyboards lying about which is on the list, just in case.

Buffered I2C expander boards seem to be on the way, so are other proto-shield type boards and I’m trying to get some “Slice of pi” boards. They seem really nice little things, break out all the pins into a little proto area and there’s even a XBee socket. And all this for under £4 including VAT! :)


Raspberry Pi Project 2 – Raspberry Pi driven digital signage and environmental monitoring

I came up with this idea at work (Oxford Brookes University) since, IMHO, our current digital signage platform leaves room for improvement. On the plus side this means we’ve already got huge modern LCD TVs hanging off the walls all over the place with additional power and network sockets next to them.
So I came up with this cunning plan to strip out the existing mini-itx PCs (which aren’t in use at the moment) and replace them with RasPi board which could then also double up as a environmental sensors platform and perform various other duties.
This is my initial project draft, any feedback is very welcome :)


The Project Draft:

Cost (initial):
The cost of a RasPi board is currently about £25 but will come down soon as production numbers increase. We have the main distributors (RS/Farnell on our official supplier list).

Cost (running):
Under full load the RasPi will consume under 3W which will be less than £1.50 per year (commercial low consumption rate) and less than what the usual 240V->5V USB power adapter consumes (<- this powers the RasPi).
The board will run off batteries for quite some time and a mid sized solar panel+small battery would be enough to run it continuously.
The board can also be run off PoE although this is not officially supported yet.

Cost (accessories):
Additional kit required to run the RasPi (estimated cost, some optional):
- 240V->5V USB adapter £5
- micro USB cable £0.50
- HDMI or HDMI->DVI cable  (depending on length) £5-25
- network cable (depending on length) £1-10 [optional]
- kb/mouse (wired, more expensive wireless options will work as well) £10+ [optional]
- USB wifi dongle  £10+ [optional]

It will connect to our wired network as well as eduroam (the later requires an additional USB dongle)
It will accept standard wired/wireless keyboard/mouse as well as other forms of input (push buttons etc)

Displaying visual content:
It will play full HD video and run a full linux desktop (Debian are providing the current official image) which means we could have it displaying:
- full HD video through HDMI/DVI (all recent TVs/screens will have this)
- due to above transmit live video feeds like the ones we have at graduation
- streaming TV, e.g. BBC HD via iPlayer works under XBMC
- slide shows/presentations
- run a browser in full screen to display whatever we have sitting on our remote webserver (news feeds, twitter streams, video streams etc)
- remote desktop into each raspi (remote maintenance, ad hoc display of content)

Displaying interactive content:
If we supply the people underneath/in front of the raspi-screen with means of input we can very easily create interactive scenarios:
- red/green button voting with live stat feed above
- feedback entry/registration forms

Harvesting environmental data:
In addition to the above the board will also happily talk to standard sensors through its I/O pins.
- The classic temperature/humidity/light level combo would cost less than £7 per node in very low volumes.
- A long range RFID/NFC reader (less than £80) would extract data from RFID/NFC tags within 10-15m range. Strategically placed at entrance/exit points this could form an attendance system if we add RFID/NFC chips to our student cards. Many users will already carry said tags in their wallet/phone so we can use these (anonymised) in the mean time to get a rough idea of attendance for lectures and events with external visitors.
- placed at store room entrance/exits this would be able to automatically keep an inventory or stored content if content is equipped with RFID tags (pence per tag)
- Addition of a RF or XBee module would allow to span a mini network around a RasPi node with more XBee/RF nodes to gather more accurate readings
- Data from above sensors can simply be stored in a database (MS/Oracle/MySQL) and then processed further for reports (BusinessObjects, QlikView, Flot etc)
- A RasPi 14megaPixel camera is about to be released so these boards could support CCTV/crowd control

Improvements compared to the current platform:

- The above will work without the need for a bought in system. Most basic system would run a full screen browser off a web server.
- A web server based backend will be easy to setup, be maintainable with a wysiwyg editor and provide the feature rich presentation of a modern web site.
- Open digital signage platforms like xibo ( should run on RasPi
- It would be possible to quickly react to newly emerging standards and content with a web server based setup
- The current system appears based on mini-itx-ish machines. These will cause a considerable amount of maintenance work due to their small form factor and hence tiny fans.
- A RasPi platform would have no moving parts, be almost maintenance free and clients would have a very long life expectancy as well as low replacement cost.
-> The platform will have a far lower TCO and especially consume considerably less power than the existing one (currently the PC and TV will draw about equal amounts, the RasPi would be negligible in regards to power consumption compared to the screen).

Additional benefit for us as a University:
Another good reason to do this with RasPi would be the fact that it is marketed specifically for educational purposes. Given it’s low price and backing by a strong community it is only a matter of time until we see students with programming skill on and an interest in this platform. Last semesters PG computing students I study with were already plotting RasPi dissertation proposals which might only get delayed due to the lack of available boards.
Having the above system in place would allow us to offer students to help improve the setup which would provide them with valuable practical experience in embedded/SOC development in general and programming for the very popular ARM platform in particular.

I shall talk for a bit about the RasPi at the Brookes OBIS away day.


Raspberry Pi Project 1 (2D/3D Pictures) – XBMC media streamer


The friendly postman left me a “you weren’t home” card yesterday so I got curious since I didn’t expect any deliveries. Farnell had given me a delivery slot for next week (28/05/2012 onwards) but a quick look into my profile confirmed that they had already sent it :) Followed by the usual 24hr wait and a somewhat restless night I finally managed to collect my first Raspberry Pi from my local main post office (at the other side of town, obviously) and documented the following “in car un-boxing” with a very happy tweet+picture :) Since I’ve been blessed with mandatory attendance at a XML training course although I have just passed a far more complex postgrad module on the matter of structured and unstructured data I had luckily already had time to prepare a repository of RasPi boot images and associated “stuff”. The following is a quick description of my first attempts to get some use out of the little board and at the end a couple of thoughts on further projects.

Raspberry Pi

1. To stream or not to stream:

Personally I don’t think that’s a real question hence the fact that during the refurb of our semi I decided to pull a bunch of AV cables as thick as my arm through the crawl space underneath the floor boards from the media center (<- she would call it the front room…) to the cupboard underneath the stairs. Said cupboard now also houses the main fan-out points for the down stairs ethernet and DVB-T wall sockets. I had a basic Intel quad core based machine in there for quite some time to basically stream video content off the central raid server and experiment with ripped HD content (<- motivated by the fact that I do own HD-DVDs and a USB HD-DVD/BluRay writer but no stand alone home cinema HD-DVD player). I think there aren’t many “stream my stuff” apps that I haven’t tried over the years and where I’m too lazy to mess with Ubuntu+VLC XBMC has proven to be a nice couche potato type front end. Since the old streaming PC was finally retired a few months ago in preparation of this setup I set out to get it to work on the RasPi. Mainly to avoid having to hook up the quad core portable to watch the last and final episode of Desperate Housewives…


2. XBMC vs Raspbmc:

Initially I thought about simply messing with the original Raspberry Pi Debian image ( to see how hard it would be to get XBMC into that but thanks to my postgrad modules I now routinely write spec and google for about half an hour before I embark on any new project. As usual this saved me about an hours worth of compiling for ARM and god knows what simply due to this website and the links on it with the two current main projects for XBMC based RasPi images: . The contenders were quickly identified as OpenELEC ( and Raspbmc (

I’ve tried both and as much as I like the idea behind OpenELEC it’s simply not quite there yet, mainly due to the fact that it feels a lot slower which is obviously the main problem on such a power poor board. Although the current Raspbmc image ( is classified as Beta it’s already very usable, boots and reacts fast and dealt well with the plugins I threw at it. Personally I’d put this down to the fact that the developer behind Raspbmc is the same guy that brought XBMC and 1080p decoding to the 1st gen Apple so he knows how to deal with underpowered platforms.


3. Raspbmc – ready, steady, boot:

Personally I got tempted to play around with the non-HDMI screen sockets but they don’t seem to be implemented yet due to missing drivers so the little thing went up against a 50″ plasma. I haven’t bothered yet to try and connect the 3.5 mm jack headphone socket to the Yamaha 6.1 Amp and I’m not sure how well Raspbmc deals with above HDMI-stereo or real 5.1 output via the 3.5mm jack at the moment but since the audio chips seems very boring standard stuff I’d assume it should simply work or require minimal work at best which I’m sure will be finished until the final image goes out.

AV wise I’ve set this up as HDMI only to the plasma with video as 1080p/60hz and stereo audio through the same HDMI cable to the TV.

I’ve seen various posts of people who tried XBMC on their RasPi with very poor results due to very slow SD-cards so I got something reasonable fast in form of a 8GB SanDisk Ultra (SDHC, 4, 15MB/s) which seems sufficient to give the little board enough I/O umpf. Building bigger lists of files can take a second or two and the same goes for listing available options in some of the plugins which scrape data off the interweb but keeping in mind the underlying system and the fact that Raspbmc is still Beta this is not only usable but actually quite impressive. The current RasPi only has a 10/100 NIC which makes sense as the chip in front of the NIC simply wouldn’t handle more (especially on the upstream side) so I’m hoping that the next version comes with a decent gigabit NIC which should be beneficial once the board is meant to crunch HD content or scrape tons of data off some website/service.


4. Raspbmc – plugins (UK):

Installing the plugins is simply down to copying the extracted files into a folder on the RasPi boot SD-card or installing the usual repositories. I’ve only tried TV ones so far which work very well. iPlayer for TV and radio works straight away after copying the plugin over, even BBCHD works stutter free! The 4oD still has this annoying bug and I’vd forgotten how to fix it but the 5oD one works without the need to turn on the brain and rewrite the messy perl script that comes with these two. TVcatchup also installs but even in low resolution the video stutters which I think is down to the codec it uses. From what I gather the RasPi doesn’t deal to well with MPEG2 but I haven’t really looked into the spec details of the GPU yet. I’d assume all this is fixable as soon as more people have the boards and feed back bugs.


5. Raspbmc – smb streaming:

No real surprises here, streaming from an Ubuntu based Samba share is simple to setup and works without flaws. I’ve tried xvid and high resolution h2.64 files and all play without stuttering which I still find amazing for a board this size :) I’ll do more tests to find out where the limits of the GPU are and which codecs it digests best but I’d assume that it should deal with all the files people usually watch and it should at least match if not even exceed capabilities of functionality built into most recent TVs/BluRay players. It surely outperforms my one year old plasma and BluRay player in regards to capabilities as a media player.


6. What next:

As usual, lots of ideas in my head :) Apart from the fact that I want to establish what the board is actually capable of with Raspbmc in regards to max video/audio rates I’d also like to test more of the XBMC plugins and hopefully I’ll get lovefilm to work on this so I won’t be sent to the mail box again ;) In regards to non media streaming projects I’m planning to try and talk to all sorts of ICs and Arduino shields once I’ve figured out what the pins do  and soldered a few dirty adapter boards. I remember this Gert-board thing and Lady Ada had a RasPi proto board in one of her blog posts but I’m not sure if either are actually on sale yet. I think the first think I’m going to try to talk to will be I2C sensors and an XBee Series 2 modules simply because I’ve got some kicking about but if I get enough spare time I want to replace the back-end of my current wireless sensor network with a RasPi. It simply needs to suck up data frames from the XBee and then store them in an internal MySQL database. Since it’s got an ethernet port it could obviously serve flot graphs on the data through Apache like my current Mini-ITX back-end but this should be a lot more portable and energy efficient. Last but not least, if said graphs and more stats/details on the sensor nodes could appear on a touch screen mounted to the back of the RasPi I would have a full MySQL storage an graphical reporting backend running off 5V and possibly even off a mid sized solar panel hence off grid :) Oh, and I still need a decent case…


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