Zumo George gets upgrades (part 1)

Everything eventually needs an upgrade. You may think that pencil 1.0 was great, but if Apple has taught us anything: we all need pencil 2.0. I jest, although that said it is time for Zumo George, one of my Raspberry Pi robots to receive the 2.0 make-over. This is brought on by two things:

Previously I had thought of upgrading from the Raspberry Pi A+ to a Zero purely to save some space, enabling me to get a bit o'real-estate back as George measure but 10cm x 10cm. However I would still have the WiFi dongle a-dongling, only it would be dangling from a micro to full-size USB. Dongles dangling from dongles (there's a song in there somewhere) made me sad: "if only a variant of the Zero came with WiFi", I thought. Fantastic news Pi fans: the Foundation delivered.

The Raspberry Pi Zero W is essentially a Zero (same CPU, same RAM, same form factor) with the added bonus of a combined WiFi and Bluetooth chip. Also for our inner geek the Foundation has included the coolest antenna I've seen yet which features a triangular resonant cavity. The MagPi magazine covered the antenna in detail just the other day in Issue 55. Proant, a Swedish company, have licensed the tech to the Foundation.
The MagPi, Issue 55. Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)

Given the move to the slimmest of Raspberry Pi's it is also time to move from the Pimoroni Explorer Pro to the Explorer pHAT. This half-pint size board has many of the features of it's larger sibling and is a perfect match for the Zero W.

Putting it all together here are collection of parts:

Zumo George Pi Zero W upgrade

Any observant bod will quickly notice something missing. Yes I hang my head in shame and join the "forgot to order a 40-pin header for the Zero" club. D'oh! eBay quickly to the rescue. Given this tiny omission the build is on temporary hold for a few days. Still, let's get the blade in place because sumo blades == awesome. While we're at it let's have a preview of where the Zero is going to go. With all ports along one long edge I can now have these poking backwards from George. You can also see the extra space I am gaining from the move to the Zero W from the A+.


I am expecting great things from the sumo blade and am already thinking about how to modify my BDD behaviours and code to take advantage: Zumo George shall no longer retreat in fear from Cartmanzilla.

Stay tuned for Part 2, entitled: "Ahah the header has arrived!"

PS: yes those wires are going to get significantly shortened ;)

The MagPi: back in print

Issue 36 of The MagPi magazine was recently released as a downloadable PDF. What ticks the awesome box though is that from this issue onwards the magazine is again available in print.

I worked on ~25 of the first 30 issues of The MagPi writing articles, proof reading and undertaking layout, and recall the fantastic feeling of seeing the magazine printed (thanks especially to Ian McAlpine). With options to purchase from several online Raspberry Pi sites as well as three Kickstarter bundles (including binder) the obvious missing link was high street distribution. The MagPi has now been under the wing of the Raspberry Pi Foundation for six issues and Issue 36 is the first to be available in the high street.

I'll say that again, with emphasis: in the high street.

It takes an incredible effort to launch a new magazine and arrange for distribution to WH Smith and similar. A HUGE well done to Russell Barnes, magazine editor and the rest of the team.

With the magazine back in print what is it like?

Firstly, the print quality is exceptionally high. The front cover has a joint matt-gloss effect with the title, most of the text and the Minecraft Splat elements in gloss on a light blue background. The cover paper used is also a fairly heavy stock and will survive some bashing (as I discovered when the magazine became an inadvertent fly swat the other day). Internally each page is full-colour and exceptionally clear and easy to read. This feels like a professional magazine in one's hand because, well, it is a professional magazine. Russell and co really know their stuff.

With an increase in size to 100 pages the spine is thick enough that the magazine can sit on a bookshelf and the identity of each issue be determined from the spine. This does show the one drawback to a magazine of this thickness in that the pages will not lie flat. It's not a big problem, but it does mean that when following code tutorials with the magazine on your desk the pages tend to curve. Firmly (but not forcefully) pressing on the magazine once or twice will open up the pages further without damaging the spine.

Yes, you did read the above paragraph correctly: 100 pages. This is the largest normal (i.e.: excluding Special Edition 1) issue of the magazine yet. Russell and his team have produced an absolutely fantastic publication with numerous hardware and software tutorials, reviews and features. A quick flip through finds 11 pages of adverts (including three asking people to consider subscribing) which I feel is reasonable for a magazine of this size (and the adverts are all Pi-relevant). Personal favourites in this issue include Extra Lives talking about retro gaming and the book review pages as these cover not only Pi-specific books, but also books of related interest. This issue a column of the book reviews pages is devoted to security and penetration testing which is an incredibly interesting subject.

The tutorials cater for all ability levels with a straightforward LED exercise in Python on page 23 at one end of the spectrum and applying physical forces to Python games to model gravity on pages 58 to 63. This is a very clever bit of code that models the movement of spheres, or celestial bodies (think: planets and asteroids). My favourite quote in the whole issue is found here:

For each planet we have, we want to calculate its effect on every other planet

That's a tough ask! Fortunately the article goes into exquisite detail on both the maths and programming needed to accomplish this.

One downside of print though is that if errors creep in then they are irreversible (unless a new print run is undertaken). Before printing The MagPi Volume 1-3 bundles we went back through every single page to update the content for the B+ (which had not been released when we wrote the earliest issues) and to correct any errors we had subsequently found for just this reason. With The MagPi issue 36, as with every magazine, a few gremlin have made it through the editing process and hence have, in print at least, become irreversible. Take the LED article on page 23 for example. The instructions and diagram show to connect to GPIO4 and GND, but the photo shows GPIO3 and +3V3 being used. Likewise, the code listing stated to use GPIO.BOARD but the pinout diagram for the Pi is numbered for GPIO.BCM. As an introductory article, "Get started with Raspberry Pi", errors like this may confuse the reader.

Despite the occasional gremlin the overall quality of the content is first rate. A lot of effort has clearly been put into the magazine. Whether you find reading easier in print or in an electronic format is a very personal thing, and with The MagPi available in both you can take advantage of both, for example: a print magazine that you can search for text within.

The new look MagPi magazine looks great, feels great and has the superb content we all expect from the publication. Best of all, the print edition is now available for a reduced price to subscribers.

Highly recommended.

The MagPi - the Foundation's official magazine

Pasted Graphic
Some excellent news: The MagPi has become the Raspberry Pi Foundation’s official magazine. A new team has been busy producing Issue 31 and it looks absolutely fantastic, reads incredibly well and is just the ticket. The original team, myself included, have produced 30 issues (and a special) of The MagPi, but with other commitments it was becoming tricky to meet the month-end deadline (you may have noticed we skipped an issue a few months back to enable us to play catch-up). Hence, with the Foundation behind it and a full-time editor on board my favourite Raspberry Pi magazine has a certain future ahead.

The new-look MagPi will continue to be available as a free download each month and will also be available for tablets soon.

Congratulations to Russell, Ben and the rest of the new team on a brilliant (thirty) first issue!



Back from SWAMP Fest

Had an absolutely great time at SWAMP Fest in Swansea. I think the count was over a hundred through the door plus lots of exhibitors, speakers, and even a Steam Punk Nerf gun seller (awesome).

I was there running The MagPi stand, fielding questions all day on the magazine and technical aspects of the Raspberry Pi. GPIO connection issues with the new Raspberry Pi B+ were a common theme. I had HDMIPi playing a loop of Big Buck Bunny to show the excellent screen quality, a Saleae logic analyser up and running showing what happens if you don’t pull up / push down the resistors for those pesky GPIO pins, and various other hardware and software demos. And yes, that is my new Steam Punk Nerf gun you can see in the background :)


I also got to meet the designers of Matboard, which was originally funded successfully through Kickstarter. They’re really enthusiastic about technology and their product, and rightly so as it fantastic. Here’s a link to Amazon where it is now available:

The event showcased a mix of Raspberry Pi, Arduino and 3D printing projects. There was also a workshop on making chainmail, which sadly I missed (my other hobby is medieval re-enactment). Robots naturally featured in abundance too.

Talking of robots, I particularly liked a tracked rover that was being demonstrated. It had been hooked up wirelessly to a laptop via XBee for control. You can make out both ends of the XBee in the photo below (the top USB cable plugs into the laptop). The track mechanism seems really stable, especially on rotation, with no hint of the tracks coming loose. Mental note: must buy tracked rover and must investigate XBee.


Swansea Hackspace had a superb 3D printing demonstration, along with lots of cool “here’s one I made earlier” objects. I’ve not had a chance to look much into 3D printing yet, so this was a great opportunity for me to ask questions and learn a bit about something new. Alongside they also had a cool plotter / laser etcher running (another technology I know little about, so was great to see).



Carmarthen Coder Dojo were running lots of programming workshops which proved popular. Their stand had a little bit of MagPi flavouring too. I’d not seen the HapPi Robot Kit before and was impressed. Bear in mind that that is a cardboard body for the robot, yet it seemed pretty sturdy.


There were also talks a-plenty throughout the day on a variety of topics. I talked about how we produce each issue of the magazine: our workflow, tools we use, how people can get involved (if you’re interested in helping with the magazine email the editor: editor@themagpi.com). Others talked about their projects and various aspects of hardware and software development. Douglas Gore from PiCymru introduced PiFun (name intentionally chosen to cause mischief), an easy to build accessory for the Raspberry Pi that turns everyday objects into touch inputs that can be incorporated into programs. Think banana piano and you’re along the right track. It’s cool to see the Raspberry Pi doing this without the need for a Makey Makey.

One thing I love about Swansea Hackspace is that they never miss an opportunity to share information. Not even when you’re sitting on the toilet. Genius!


I also spent an enjoyable evening in the company of the members of Swansea Hackspace, which started with me attempting to take a selfie via their webcam. They’re a great group of people. If you’ve never been to a Hackspace before and are looking for a friendly, productive atmosphere in which to tinker you should definitely get in touch.


It was a fantastic, enjoyable day. If you’re reading this and wondering about whether to go along to similar events in the future then I can highly recommend them. They’re a place to learn, have fun and see things that make you smile and say “that’s cool” a lot.

SWAMP Fest time

Off to SWAMP Fest in a few minutes. Nope, nothing to do with marshy terrain, but everything to do with technology. If you’re going, I’ll see you in Swansea in a few hours.

The MagPi issue 23 is out - and Ethical WebSites is sponsoring the competition

It’s great to see The MagPi reach its second birthday with the release of issue 23. For those that don’t know, I’m one of the editorial / layout team working behind the scenes on this great magazine. I also run Ethical WebSites, a web development business in the UK.

For issue 23 we’re running a huge competition (details on pages 18-19) with over £2000 of prizes. As part of this I decided to donate two domain name + hosting (with full control panel) packages to the first and second prize winners.

Oh, and I’ve also a special offer for anyone wanting to host Raspberry Pi related projects online - take a look at the top banner item at Ethical WebSites and follow the [more] link you’ll find for more information.

Happy Birthday MagPi :)

Issue 17 of The MagPi released

Issue 17 of The MagPi has been released in PDF and online (via Issuu) formats.

Of note in this issue, and for those of you who didn’t see the Kickstarter (which raised a crazy $127,537 on a goal of just $1,889), this issue covers BrickPi in depth. BrickPi is an easy to use shield that sits on your Pi and lets you control LEGO® Mindstorm sensors and motors. Now the clever thing here is that LEGO® will happily sell you the parts without buying the actual Mindstorm kit, ie: you can save money by not forking out for the NXT Intelligent Brick and get much greater freedom of control by using your Raspberry Pi instead. This is a very neat shield.

In addition some other highlights include articles on eye tracking (which has the unfortunate side-effect of making the user look like a founding member of the Borg Collective), an interesting aside on the DS18B20 digital temperature sensor, using the Serial Peripheral Interface (SPI), and using long range radio communications make for great reading.

Raspberry Pi Handbook magazine magazine out now

The postman dropped off something I’ve been waiting to see for a while, the Raspberry Pi Handbook, a Linux Magazine Special (#14). 98 pages of Pi goodness with very few adverts makes for a compelling read. Although the price tag of £7.99 feels a little steep that’s the price of more content and less adverts hence I feel it is justified.
Inside you’ll find lots of new articles on the Pi covering the OS and software, programming and hardware hacking. There’s a particularly interesting article on hooking up a USB weather station to the Pi and outputting the data recorded via a web server (also hosted on the Pi) that I think I’ll be trying out. There is also a very interesting interview with Eben Upton that is worth a read, noting that this interview is available to read for free online. The magazine comes complete with a DVD containing a number of different operating systems for the Pi which is handy to avoid potentially lengthy downloads in some cases, albeit at the price of the ISO images burned to the disc eventually becoming out of date.

The magazine also includes several articles re-printed from The MagPi and it is good to see The MagPi (even if only in part) making its debut on the shelves of WH Smith.

One thing I especially like about the Handbook is that it rapidly goes from beginner to advanced without feeling the need to trudge through endless “this is what a keyboard is: you press the keys and magic happens” very basic introductions to the Pi. There is a lot of straightforward stuff contained in the magazine but the reader is rapidly taken on to advanced topics including compiling from source. Good to see.

Raspberry Pi Handbook, available from... well pretty much anywhere that sells magazines.

Issue 14 of The MagPi released

Issue 14 of The MagPi has been released. This issue contains a review of the Bristol Raspberry Pi Boot Camps that RaspTut has been attending along with The MagPi. Also in this issue is the first in a series of articles about the new camera board add-on available for the Pi.

As always, the magazine is available for free to read online or download as a PDF.

The MagPi: help wanted

The MagPi
Well we’re almost there with Issue 11 of The MagPi. It is truly incredible to see how much effort goes into each issue. From authors to layout to graphics designers, to proofreaders and the testers it is the community that has sprung up around the magazine (and the Pi of course) that makes the magazine such a success. I’ve discovered that the opportunities to be involved are virtually endless. I’ve written several articles for the magazine but at the moment am concentrating on layout, proofreading and testing if only because it gives me more time to read all of the great stuff others are writing about.

Then on top there’s the events? Did I mention them...? No...? Well back in December Meltwater (of The MagPi ofc) and I attended an event at @Bristol in, um, Bristol that gave us the opportunity to meet a few hundred young people and assorted parents and teachers. We had Pi’s on display running various software and hardware demos, and some additional GPIO gadgety-things for all to ooo and aaahh at. All under The MagPi banner. This month we are back at @Bristol for another 200+ young person event. Superb and great fun! Others are attending / running their own Raspberry Pi events and the team at The MagPi is always available to support each other in these escapades.

So this is a shameless plug: if you’re reading this and you read The MagPi and have thought: “hey I could write an article on Gadgety-Widgety-Thing” or “I like those graphics, but I think there should be more pink” (or neon green...) then The MagPi will more than welcome you. Email the editor for more information. And if I meet you at an event then I’ll buy you a beverage of your choice to say thank you.

The MagPi issue 7 is out

The MagPi issue 7 has been released. What’s more I have two articles published in this issue: an interview with Mike Thompson who created Raspbian, and my first ever published computer program! I took over The Python Pit this month to demonstrate how one can implement command line arguments to make configuring an application that is about to be run easier than having to manually edit the program code.

I am especially pleased with the program I wrote as it generates graphical output (see image below) that I used to draw by hand when I was a child. Back then I don’t even think it occurred to me to write a program to do this!


The program supports a number of command line arguments to change the output. Run:
line_generator.py -h
to see all of the options.

For your viewing pleasure, here’s the output of the above:

usage: line_generator_edit.py [-h] [-s SCALE] [-t STEP] [-r {y,n}]

Render shape

optional arguments:
-h, --help show this help message and exit
-s SCALE Render size, default=2, 200x200px)
-t STEP Step value (default=5): lower the value for denser lines
-r {y,n} Render line by line (slower) (y) or only display finished object
(faster) (n)? (default=y)


The MagPi Issue 5 featuring an article on XBMC

The MagPi issue 5 has been released. This issue contains an article on XBMC written by yours truly. I have been really impressed with the recent performance and feature improvements to both OpenELEC and Raspbmc and I attempt to cover some of the great new stuff that is available, like CEC, in this article.

Read and enjoy :)

The MagPi: now available in a printed edition

Everyone’s favourite Raspberry Pi magazine, The MagPi (www.themagpi.com) is now available in print edition for issue 6. You can order it online from ModMyPi direct. The magazine also remains available as a free electronic download.

Oh and good news: I spoke with The People In Charge and they were able to drop VAT from the purchase price of the hard copy as magazines are zero rated over here.

The MagPi is produced by a collection of individuals from different backgrounds (including yours truly), all with an interest in computing and the Raspberry Pi. Each month provides articles and interviews covering a wide range of hardware and software projects. Issue 6 features an interview I undertook with David Hunt of Camera Pi fame along with many other excellent articles and tutorials.

The MagPi Kickstarter campaign

The MagPi magazine is now running a Kickstarter project with the aim of getting printed copies of all 8 issues in volume 1, plus a special binder to hold them all, into your hands. From the Kickstarter page:

Bring The MagPi magazine, the best and only magazine for the Raspberry Pi enthusiast, from the digital realm into the physical realm.

I’ve posted a fair bit on here about The MagPi, in part because I write articles for the magazine, but also because I genuinely believe it is a superb read with excellent well thought out articles. I’ve learnt lots by reading each issue and have seen the team grow in strength and capability over the months. This means that each issue is a valuable resource to help anyone of any experience level to get more from their Raspberry Pi.

The current issue shows just how detailed the articles are by presenting a foolproof way to catch Father Christmas (oh ok then... “Santa”) later this month. Now in my eyes that alone is worth contributing to the Kickstarter project (anyone remember the Red Dwarf episode Backwards?)

Please do support the Kickstarter project.

The MagPi issue 6 is out

The MagPi issue 6 has been released, featuring an interview written by yours truly with David Hunt of Camera Pi fame. Camera Pi is a superb amalgamation of Pi + DSLR camera that gives David lots of control over the photographic process.

The MagPi issue 8 is out

The MagPi issue 8 has been released, featuring my second ever published program when I take over The Python Pit again. This time around I show how to use Python’s subprocess to create desktop widgets. Think: those things what Windows Vista and 7 has and you won’t be far off.

The Python program has an intentional flaw, but I only reveal general details on this to the readership. This is by design as one of the things I always liked about programs in those 1980s computer magazines (you know, the one’s that listed the code and you had to type it yourself back in the days before cover cassettes / disks or discs became the norm) was that you often had to finish the program off, or improve it to get it to work _just_right_.

If you are reading this I’ll let you know a bit more detail to help you out.

As I note at the end of the article, refreshing the Pygame screen for each widget occurs at the same time as each checks for new content. The problem this causes is that if I drag another window on top of either Pygame window it will blank the output until the next check for content, which could be hours away. The fix is quite straightforward and involves adding an if statement that uses datetime to determine when to check for new content, and changing time.sleep(28800) and time.sleep(3600) to both be time.sleep(1). This means that each pygame widget’s screen will refresh every second (change this to 0.1 for faster refresh, every tenth of a second, at the cost of higher CPU usage by Python) BUT a check for new content will still only happen periodically when the new datetime value is suitably different from the old datetime value. You do NOT just want to change to time.sleep(1) on its own as this will cause both URLs to be queried every second for new content which is much too frequent.