In this work we present an hybrid device based on two infrared and one ultrasonic sensors. We think that this approach has the goal of simplicity and is very cheap in comparison with a lot of other technology especially with those based on the image processing.This reduction of components comports a little consumption of energy and then a great autonomy. On the other hand our hybrid approach, combined ultrasonic and infrared technology, allows us to take the best property of the two kind of sensors. The ultrasonic sensor has the possibility to intercept any kind of surfaces in contrast to the infrared one that cannot intercept glass or mirror. On the contrary the infrared sensor has the property to have a little spot,with respect to the ultrasonic sensor, then gives the possibility to intercept better the position of an obstacle.