GAINESVILLE, Fla. -- The hours of sweaty, dusty, laborious lawn mowing may soon be over, thanks to a robotic lawn mower under development at the University of Florida's Machine Intelligence Lab. Using a high-tech combination of radio, sonar and infrared detection, the mower can find its way between the plastic pink flamingo and the swing set without chopping up your flower garden. A radio wire buried at the perimeter of the yard will keep the robot "fenced" in. Around the perimeter, users will place three beacons that respond with an infrared burst to a high-frequency sound pulse from the robot. This infrared burst allows the robot to determine its position in the yard using conventional triangulation. The robot can also keep track of where it has already mown. The mower will carry other infrared detectors and a sonar system to keep it from crashing into birdbaths or the family pet. Christened the LawnNibbler, the machine will run off a 12-V deep-cycle battery similar to those used for trolling motors. Although a complete prototype has not been developed as yet, lab director Keith Doty said that the designers are aiming for about two hours of running time before the mower needs to be recharged. "Energy efficiency is important," said Doty. Energy consumption is behind the lab's decision to make the unit small and to use nylon cord instead of the traditional heavy mower blade. Doty said that the development of a prototype depends heavily on venture capital. If he can round up investors for the project, a prototype could be ready about a year after the money is available. He also said the lab is working on an autonomous vacuum cleaner and attempting to resolve suction problems associated with battery-powered vacuums.