The infrared sensor chosen has a range distance that goes from 20 to 150 cm, a resolution of 0.5 cm, a frequency of 26.3 Hz and an analogical output that goes from 0 to 5 V. This sensor is characterized by a little spot and high precision. But the problems of these kind of sensors are the impossibility to intercept some kind of surfaces (like mirrors or glasses) and the interferences caused by light.The last problem is solved by the Sharp-GP2Y0A02YK0F thanks to its main circuit that triangulates three different signals.