Computing infrastructures of mobile robots have grown in complexity in the last decades; They have evolved from single processor systems to networks of microcontrollers communicating through a shared bus. This has induced additional architectural constraints that do not fit well with the traditional polling-based sensors and actuators control. To address this issue, we have developed ASEBA, an event-based middleware that allows distributed control and efficient resources exploitation of multi-microcontrollers robots. ASEBA provides hardware modularity, better efficiency, and improved scalability by embedding a lightweight virtual machine in each microcontroller and providing an IDE to develop and debug the whole robot reactive control from a single place.