Besides environment sensing, robot perception can be also aimed to interact with human users. To make comfortable this reciprocal action, usually the sensor system requires an intelligent interface.In particular, the paper describes an integrated guidance system for a low-cost wheelchair prototype to allow disabled people to move autonomously in the environment. The driving system consists of an obstacle avoidance module, a simple vocal command interpreter and a head position sensor to steer the wheelchair itself.After presenting the whole system, this paper deseribes in detail the head-activated device, the related signal processing and the methods used to reduce interactions between the wheelchair motion and the sensed values. Finally, integration with the overall driving system and experimental results will be presented.