Optical sensor in control of LEGO robot

Nowadays, technical schools are facing the problem of how to teach a new generation of engineers. Case studies and practical teaching seems to be very helpful beside interactive courses and e-learning. LEGO Mindstorms, a very common building kit, is widely used for teaching the basic principles of robotics. Even for universities, it offers many possibilities to improve the teaching process. In laboratories the students experiment by measuring with optical sensors — cheap web cameras. In the paper a short theory about the single camera distance measurement will be introduced and demonstrated on a practical experiment. In fact, the LEGO robot, with certain basic equipment, is used as a controlled system and the PC with camera serves here as a controlling system. The paper deals with the construction of whole feed-back control loop with all aspects and relations between the items. The authors also discuss some specific problems which occurred and propose solution.