In this article, the author describes how electronics students at Central Nine Career Center designed a kill switch circuit to stop a runaway lawnmower. This project is ideal for a career center since the electronics/robotics, small engines and horticulture classes can all work together on their respective parts of the modification, installation and use process. The kill switch circuit should not be used as the only means of operator training or protection. The circuit could "fail" in a number of ways. Procedure, materials and schematic diagram of the circuit are presented.