The VPM2 vibrating motors are produced by the Solarbotic just for this kind of applications. The four vibrating motors are located two on the front and other two on the backside of the user. This choice allow us to distinguish positive and negative obstacles in front of the left and right feet of the user and to make the interpretation of the signals as simple as possible. For example if there is an obstacle in front of the right foot will vibrate the motor located on the right front vice versa if there is a descendent step in front of the left foot will vibrate the motor located on the left backside. In Fig. 1 is shown the prototype of our device with all the components presented before.