Development of a Prototype Autonomous Lawn Mower Using GPS and Boundary Wire Sensing for Institutional Grounds in Cross River State

Maintaining large institutional grounds such as university campuses and government estates in Cross River State, South South Nigeria, involves significant manual labour costs and safety risks associated with conventional petrol-powered lawn mowing equipment. This project presents the development of a prototype autonomous lawn mower that uses a boundary wire sensing system combined with GPS guidance for navigation within predefined mowing areas. The mower employs a boundary wire buried at the perimeter of the target lawn area, which emits a low-frequency electromagnetic signal detected by receiver coils on the mowing unit. An Arduino Mega microcontroller integrates boundary detection signals with a GPS module to navigate within the defined zone while systematically covering the lawn area in a serpentine pattern. Two DC gear motors drive the rear wheels, and a 12-volt DC motor powers a rotary cutting blade. Random directional reversal is employed upon detecting the boundary signal to ensure coverage uniformity. The prototype was tested on a 200 square metre lawn area at the University of Calabar botanical garden. Lawn coverage completeness over three consecutive mowing sessions averaged 88 percent without manual intervention. Battery endurance was 72 minutes per charge, sufficient for the test lawn area at the set cutting speed. The study documents performance limitations including handling of steep inclines and proposes a future design with tilt sensing for slope management. Keywords: autonomous lawn mower, GPS navigation, boundary wire, institutional grounds, Cross River State