Completed the characterization, it is possible to understand that the infrared sensors are able to intercept correctly the presence of obstacles thanks to their little spot. Then, we decide to locate the min order to aim in front of each foot, one on the left and one the right,with a particular inclination (discussed in Section 2.5) with respect to the horizontal position. In this way the two infrared sensors can discriminate if the obstacle is in front of the left or of the right foot.If both sensors give a signal this means that there is an obstacle in front of the user. Instead, for what concerns the ultrasonic sensor,being it less precise, we used it to intercept vertical obstacles in front of the user maintaining it parallel to the floor. In this way we can, as discussed before, make the whole system more reliable.