The sensorial system is composed by two infra-red emitter/receiver sets, as shown above. Each of them is mounted on a stepper motor, attached to the mobile platform. A band-pass filter (around 6 kHz) and an amplifier following the two infra-red sensors, detect the reflected beam emitted by themselves. Two passive reflectors, of cylindrical shape, are placed on the docking station (see figure).
The received signal is then converted to digital by the PIC (which has an internal A/D
converter) and returned to the mobile robot's on-board computer.
The vectors corresponding to a 144 degrees (80 steps) sweep of each sensor are then processed, and local maxima are extracted. These local maxima represent, with fair chance, the angle with which the sensor detected the reflector.