Saturday, October 20, 2012

Building the Gertboard

I got my hands on a Gertboard the other day, and decided I would document the creation of it.

The first thing I saw when I opened the bags of kit were the SMD components - which scared me somewhat - having done a lot of soldering before but never with surface mount.  Still, the assembly manual included some good advice, and I wasn't too nervous about soldering them.

Elastic band around pliers to make life easier
Look! No Hands!
I went through the parts list, and realised that none of the SMD resistors or capacitors had their values on them, so had to look up all of the part codes on the Farnell website.  Not a big deal, but a bit of a pain, and beginners may get confused by having to do this...

Then I set off.  The advice on soldering SMD in the manual is very well written, and I had no issues when I followed it pretty much to the letter, despite not having decent tweezers, and having to find a couple of errant resistors which had pinged across the desk on a few occasions!

Firstly, a couple of tips.  As you can see in the picture to the right, I tightened an elastic band around my pliers to hold them together - this makes holding things in them a hands free operation, and make life a lot easier!  I also pre-soldered one of the two pads for all of the SMD devices, which meant I could easily identify them and could spend more time concentrating on the fiddly bits.

Using the IDC connector to keep header pins straight
Using the IDC connector to keep pins aligned
Secondly, the tip in the assembly manual which recommends using a sponge to keep the components flush with the board is a really good idea for the components, but it doesn't help keep the headers aligned.  I did this by using the ribbon cable IDC connector - also pictured, to ensure that the headers had the right spacing.  I could even use it for the long headers by using it at 90 degrees to the normal direction - between the joins between the sections of header.

All in all, the assembly went pretty smoothly, and (as I didn't have my multimeter to hand) I decided to risk it and went ahead and powered the board up straight away - without testing voltages, etc - I wouldn't recommend this, but I got lucky and it worked first time - I only checked with the button demo, I'll be playing with it more over the next few weeks / months.
Completed, connected gertboard with jumpers ready for the button.c test program
The completed board, wired for the button test
Running the buttons test on screen with the output shown
The button test running on the pi (sorry for the quality of this one!)
Finally, if you've held on for this long, here's a 1 minute rendition of me building the thing in stop motion...

Monday, October 15, 2012

Long time no blog!

Sorry for the long silence; I've been mentally busy at work, etc.

There's been a lot that has changed since I've been quiet; The Raspberry Pi is available at other stores (Maplin, CPC), has twice as much RAMRaspian is the new recommended image (and it's great, I love the automatic configurator that starts on first boot!), and Eben's released books 'Beginning Raspberry Pi' and 'Raspberry Pi User Guide'.  There's certainly some amazing stuff going on!

Anyway, my media centre project is going well.  I opted for Raspbmc for my RasPi media centre over OpenElec in the end (I'll post in more detail about this later), and it's working great!  I'll post soon about that, as well.  On the downside, I've had issues with my chosen USB Satellite decoder, it seems to be much more susceptible to slightly poor satellite signals compared with the PCI one I have in my Linux desktop, so I've switched back to that for now running TVHeadend.  When I get around to it I'll try the USB decoder/RasPi combo in a different place with a known good satellite signal.  If that works, I'll get a man in to repoint my dish! - I'm still hopeful that I can make something work with this.

In the meantime, I've consolidated my files, and got the Pi working as an Apple Time Machine server, which works really well - I'll be blogging about that shortly.  My intention is to take a Pi and an external HDD to a friend's house, when I'm there (on their Wi-Fi) my Mac will automatically back up to the Pi, and for only £ 25 more than the cost of the drive.

Also, my Gertboard arrives soon.  Hopefully I'll be able to work out how IO works properly then and put some more blog posts up.  Given time!