We are using Swiss designed mobile robots called e-pucks. These remarkable miniature wheeled robots can run around powered by their own motors and wheels; they can see (with a camera), hear (with microphones), have a sense of touch and balance, can make sound and light signals, and communicate wirelessly via bluetooth. For full technical details on the e-puck check here.
Although a powerful robot in its own right, the embedded micro-computer in the e-puck doesn't meet the needs of this project, so we have designed a Linux plug-in card. The Linux enhanced e-puck is capable of running the significantly more complex behaviours that we are designing in this project. It also adds wireless networking (WiFi) to the robot, making it much easier for us to track and monitor what's going on in each robot.
Here is an e-puck with the Linux board fitted in between the e-puck motherboard (lower) and the e-puck speaker board (upper). Also note the yellow 'hat' which here serves three different functions: (1) it provides a matrix of pins for the reflective spheres which allow the tracking system to identify and track each robot; (2) it provides a mounting for the USB WiFi cardwhich slots in horizontally (the wires connecting to the WiFi card are above the USB connector); and (3) it provides an inverted cone to reflect sound from the e-puck's speaker horizontally so that it can be heard by other e-pucks.
Normally the robot would also be fitted with a coloured skirt around its body and wheels, so that it can be seen and identified more easily by the camera of another robot.
Here is the Linux board, designed in the Bristol Robotics Lab by Wenguo Liu, shown with its USB WiFi card. (The normal casing of the WiFi card has been removed.)
Check the robot image gallery for more pictures of the robots.