Dan Aldred, who created the mighty Pi Glove has used an Energenie Pi-mote IR sensor board to pick up the infrared signals for his (pretty darned cool) robot and then used the Pi to re-transmit the signals according to his program or web interface. You can read his write-up and tutorial over on his blog.
Open Sourced robot
Keith Ellis and the guys over at Ipswich Makerspace did brilliantly well with their robot, TractorBot, at last year Pi Wars. They won Best Robot under £75 and placed very respectably in most of the challenges. (You can see the full results here). They have decided to open-source their designs and code for TractorBot, which means that other competitors this year will have a head-start on many challenges if they take the time to go through the code. Design specs will also be released so if you want a good base to start from, you could do far worse than take a look! You can read the start of their open-sourcing project here.
Sacramento-based Chris Osborn likes to control fireworks with electronics. This year, he decided to use the Raspberry Pi to trigger relays that would ignite the fireworks. In the end it didn’t work brilliantly well, but he’s blogged about it and included a wiring diagram for his set-up. Read more here.