In the UVic computer science department’s real-time systems course, CSC 460/560, we have been using the iRobot Roomba as a platform for mobile distributed real-time systems. The Roomba, controlled over its serial port by a microcontroller, gives students access to its motors and sensors through an interface that’s easy to use. They can then focus on real-time software design instead of mechanical design or low-level details such as actuator control and analog and digital sensor I/O. iRobot provides a very good document presenting the Roomba Serial Command Interface [PDF, 262 KB], or SCI. This report expands upon the SCI manual by summarizing some of its information and recording some details that we have discovered.