Previously on I Heart Robotics, we featured a video of the ColonyScout project being developed by the Carnegie Mellon Robotics Club. Following up on that video we have located their website, which is full of information about the project.
The ColonyScout robot is equipped with an AVR Microcontroller for motor control and management of the main sensor suite, including sonar, IR and wheel odometry. Computationally intensive tasks such as communications, IMU Management and path planning are handled by an ARM9 Microcontroller which runs a RTOS.
The suspension system and 4WD looks really effective for outdoor use.