Wheely is a robotized wheelchair prototype built at the robotics lab of the Università di Roma Tre. The vehicle has two driving wheels equipped with incremental encoders. Five ultrasonic sensors with a radiation cone of about 90° are available. The first sonar is oriented in the forward direction, while the other two couples make an angle of 55° and 90°, respectively, with the forward axis. The control software runs on a on-board notebook 486-PC equipped with a data acquisition card (DAQPad 1200 by National Instruments), and has been developed using the graphical language LabVIEW, while some of the most time-critical routines have been written in C.