Monthly archives: May 2012

PhidgetSBC2 and D-Link DWA-160

So I've had a little project going on with the foosball table at work: a system to detect when someone scores a goal. I've built a prototype photogate that goes inside of the goal. My design is to have 2 photogates hooked up to my PhidgetSBC2 and write some ruby code to detect a goal and send a message to a connected iPad app to indicate who scored. Everything was going fine until I took the PhidgetSBC2 to our foosball table and discovered our 2.4GHz network had no coverage there. Which means the wifi usb adapter I had for the PhidgetSBC2 was useless. Undeterred I started on 2 different solutions.

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PhidgetSBC2 and ruby

Installing ruby (and the phidgets-ffi gem) on the PhidgetSBC2 is fairly simple. You will need to check Include full Debian Package Repository under System > Packages in the SBC admin page. And then just ssh into the server and run the following:

apt-get update && apt-get install ruby1.9.1 ruby1.9.1-dev build-essential -y

And then you can install the phidgets-ffi gem like so:

gem1.9.1 install ffi phidgets-ffi

The gem doesn't find the libphidgetsbc.so.0 on the PhidgetSBC, so we need to symlink it to somewhere that the gem will find it.

 ln -s /usr/lib/libphidget21.so.0 /usr/lib/libphidget21.so

Once we're done this we can test it with this:

ruby1.9.1 -rphidgets-ffi -e 'puts Phidgets::FFI.library_version'

I also like to run this to add the ruby1.9.1 executables (i.e. rake, irb, gem) without the 1.9.1 suffix.

update-alternatives --install /usr/bin/ruby ruby /usr/bin/ruby1.9.1 400 \
--slave /usr/bin/erb erb /usr/bin/erb1.9.1 \
--slave /usr/bin/gem gem /usr/bin/gem1.9.1 \
--slave /usr/bin/rake rake /usr/bin/rake1.9.1 \
--slave /usr/bin/testrb testrb /usr/bin/testrb1.9.1 \
--slave /usr/bin/rdoc rdoc /usr/bin/rdoc1.9.1 \
--slave /usr/bin/irb irb /usr/bin/irb1.9.1

I also like to create an .gemrc to skip installing ri and rdoc documentation to save on space.

echo install: --no-rdoc --no-ri >> ~/.gemrc
echo update:  --no-rdoc --no-ri >> ~/.gemrc

StartSSL cert with mumble-server on Ubuntu 12.04

With the release of Ubuntu 12.04 I decided to upgrade the server running my mumble server and I wanted to use my new wildcard certificate so my mumble server would have a nice shiny green background. All went well with my upgrade to 12.04 and getting nginx to use my certificate was easy. Next was to add my certificate to mumble and then I ran into a problem. No matter what certificates I provided to the config (sslCert and sslCA) I would always get his error when a client tried to connect.

1 => <1:(-1)> New connection: XXX.XXX.XXX.XXX:XXXXX
1 => <1:(-1)> SSL Error: No certificates could be verified
1 => <1:(-1)> Connection closed: [-1]

Long story short: I added the ca-bundle.pem from StartSSL to /etc/ssl/certs and then it all worked.