A lighting system comprising a lamp arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature, direction and beam cone angle; a light control means arranged to adjust said light beam properties; at least one ultrasonic transmitter arranged to transmit ultrasonic signals; a plurality of spaced apart ultrasonic receivers arranged to receive reflected ultrasonic signals; and a processing means arranged to determine for each of said receivers time-of-flight signals representing the time differences between said transmitted signals from said at least one transmitter and the associated received reflected ultrasonic signals from said receiver, and to send control signals to said light control means in dependence of the combination of said time-of-flight signals for each of said receivers. Said ultrasonic transmitter and one of said ultrasonic receivers are arranged on a rotating means for moving along the circumference of said lamp.