Tuesday, 12 June 2012

The PlyPi - my Raspberry Pi computer and handmade case

May I introduce you all to the new addition to our family?

Raspberry Pi - PlyPi - Happy Families
Pi and Owner together with a free T-shirt...got to love a free T-shirt!

So small, and yet so full of potential.  Certainly doesn't come with any instruction manual but there's plenty of opinion floating about online (and in forums a lot less scary than Mumsnet).  This is my baby.  And I'm already so so proud.

The Raspberry Pi, to those of you not in the know, is a tiny piece of British computing.  It comes in at £25 for this, the top spec Model B.  For your hard earned Pony, you get a 700mhz processor, 256mb of RAM, two USB ports and an Ethernet port.  It uses HDMI for digital video output and is powered by a 5v Micro USB mobile phone charger.  The OS and any programmes/files you create are stored on a single SD card.

Raspberry Pi - PlyPi - Board
The Raspberry Pi Board

The idea behind this little slice of genius is to encourage people back to the magic of true computing, rather than sucking at the consumerist teet of all things easy.  Children in schools, it's hoped, will all be able to own one.  And just as kids will customise pads of paper and books with stickers and messy ballpoint pens, so they will customise their Pis.  In so doing, they will learn about the beating heart of what makes our world work.

Of course, it's not all about kids.  Already I've seen a dozen projects of great originality and fun.  A low powered machine running Linux can do *so* much it's mind-blowing.  My own dreams are much less grand.

Raspberry Pi - PlyPi - Pins
The Pi comes with plenty of pins so that clever people can take over the world

First and foremost I wanted to have a computer I could really play with.  It's all well and good experimenting with your every day computer, but the fact is that if you do something wrong you risk not having access to email, losing important files etc.  This way, if the very worst happens, I can just wipe the SD card and start again from fresh.  Also, being a Linux OS (currently Debian Squeeze) I get to have the fun of playing with the command line.  I like the command line.  It feels polite.  Most of the time we prod at buttons, lacking the courtesy to ask nicely for what we want.  Command line is please and thank you.  And what's more, you're able to do pretty much everything from one place rather than having to trawl through the desktop menus to find the one thing you want.

One of the first things I learnt to do was to tweet from the command line using Twidge

Secondly I liked the idea of simple, low power consumption computing for things like word processing.  I've installed Abi Word and, with my Filco keyboard hooked up, I can't think of a more appropriate word processing machine.  Forget wifi internet access - unless I go to the trouble of plugging in the ethernet cable, I'm without the net.  And anyway, if I start trying to do both at the same time, things will slow down.  So it makes sense to be disciplined and single minded in your writing.

Raspberry Pi - PlyPi - Case (Ethernet/USB)
Looking straight on at the Ethernet port (which was heavily recessed) and the USB ports

Thirdly, I've been wanting to scratch build a computer enclosure for a very long time.  I'd dreamt of doing something with mini-itx as I didn't care about great power and wanted the finished item to be small.  Small?  Mini-itx is massive in comparison to this thing!  Just take a look of it in comparison to my HTC Desire.

Raspberry Pi - PlyPi - Case vs HTC Desire
Size comparison between finished PlyPi and HTC Desire Smartphone

So here we have it - 3mm plywood layers cut carefully on my rusting, aged scroll saw.  Honestly, it shook so much I expected it to fall apart.  I will hopefully upgrade the machine at some point which would make the whole thing easier (poor cutting depth meant I could only cut one layer at a time).  The eight layers were split 3/5 and glued to form the top and bottom.  I 'temporarily' glued the two layers together with Tesco own brand pritt stick, only to find afterwards that it was the strongest glue in the world!  With the case in one block I was able to sand it down to even up my poor cutting and, after drilling the four bolt holes, finish to 400grit.  It was then (eventually) split into the two halves and coated with sanding sealer and wax to keep it looking as natural as possible.  In the original design I'd been thinking about a flower press and had intended to use wing nuts on top.  However when I fitted some temporary (too short at 25mm) machine screws, I was rather taken with the look.  So the case was finished with 30mm M4 stainless button head bolts with stainless washers and dome head bolts (which then acted as feet).  It's easy to undo the dome heads with your fingers and then gain access to the Pi.

Raspberry Pi - PlyPi - Case (Audio/Analogue Video/Dome Nut) Raspberry Pi - PlyPi - Case (Ethernet/USB/Bolt) Raspberry Pi - PlyPi - Open Case and Bolts
Close-ups of nuts and bolts and an image showing the split PlyPi and fixings

I had thought about leaving a hole to view the LEDs, but as my initial use will be less experimental (globally speaking - it's pretty experimental to me!) I don't see this as a great problem.

Raspberry Pi - PlyPi - LEDs
Close-up of the LEDs which have been left covered - design flaw?  Or sacrifice to aesthetic perfection?

As it is, I like the simplicity.  Frankly I think it's prettier than anything Apple could do.

Raspberry Pi - PlyPi - Case (Audio/Analogue Video)
Isn't it lovely?

So there you have it.  I've already learnt all manner of exciting things and there's so much more to come!