In september of 2002 the Roomba was invented by IRobot as a easy alternative to the labour inducing vacuum cleaner. It uses two independently operating wheels that allow for 360° turns in place. All Roomba models are disc-shaped, 34 cm (13") in diameter and less than 9 cm (3.5") high. they follow a set path and use sensor technology to avoid bumping into walls and objects.
There have been many models releaced by IRobot, from the 400 to the 900 series, each with their own updates and capabilities.