US Patent 9405294 Method and system for guiding a robotic garden tool

Method and system for guiding a robotic garden tool (100) is disclosed. The robotic garden tool (100) may include at least two sensing means (108, 110, and 202). The robotic garden tool (100) is equipped to follow along a guiding wire (402) on a lawn (400). While the robotic garden tool (100) moves along the guiding wire (402), the sensing means (108, 110, and 202) may detect a magnetic field strength generated from current carrying guiding wire (402). The method (500) and the system (300) is equipped to provide instructions to the robotic garden tool (100) to follow the guiding wire (402) based on the difference of magnetic field strength sensed by at least two sensing means (108, 110, and 202).