A method of avoiding collision between mechanical equipment (10) and obstacles, and a device and controller for this, by detecting whether an external conductor is approaching the device (10); when detecting that the external conductor is approaching the mechanical equipment (10), generating an electrical signal representing a distance between the external conductor and the housing of the mechanical equipment (10) or a change of the distance between the external conductor and the housing of the mechanical equipment (10); controlling the mechanical equipment (10) based on electrical signal so as to avoid the mechanical equipment (10) from collision with the external conductor or to reduce a strength of the collision.