Roomba is a robotic vacuum cleaner made and sold by iRobot. It is marketed as a Robotic Floorvac. As of October 2004, 1 million units has been sold.
The unit is a disc, thirteen inches (34 cm) in diameter and less than four inches (9 cm) high. A large contact-sensing bumper is mounted on the front half of the unit, with an infrared sensor at its top front center. Besides the on/off switch, there are three buttons on the unit marked 'S', 'M', and 'L'. A carrying handle is fitted on the top of the unit. It also comes with a "virtual wall" infrared transmitter unit which can be used to prevent the Roomba from going into areas its owner wants it to avoid. The Roomba operates with internal batteries and requires being recharged regularly from a wall plug, although newer Discovery models have a self-charging base they can automatically find.
Using the Roomba consists of carrying it by its handle to wherever the owner would like it to start, turning on the power switch, then pressing any of the three buttons to tell the Roomba how large the room is (small, medium, or large). The buttons control how long Roomba will operate until it decides that it's finished.
When a button is pressed, Roomba beeps a few tones, then begins its work. First models were not smart enough to vacuum a room's entire carpet in an orderly fashion, instead they used a simplified random walk algorithm which allowed them to cover much of the floor without needing to map out its terrain. Simple sensors detected bumping into walls and furniture, as well as "virtual walls" used to limit Roomba to certain parts of the room. Newer models have additional visual and sonic sensors that allow them to detect particularly dirty spots and change the mode of operation accordingly and to keep away from dangerous stairs.
The net result is that Roomba reaches most of a floor regardless of room configuration. After a preset length of time (decided by whether the owner pressed S, M, or L), the Roomba stops and beep a few triumphant notes. The owner then removes the dustbin from the unit's rear and empties it into a trash can. Newer Roomba models will automatically return to a charging base station after finishing.
The Roomba is not as effective as a traditional vacuum cleaner at deep cleaning, but it does a good job of picking up dust, lint, and carpet fuzz. It can sense stairs and other ledges and avoid them (with varying success), and it is also low enough to go under a bed or other furniture. If at any time the unit senses that it has become stuck (on rug tassels, for example), it no longer senses floor beneath it (it has been picked up), or it decides that it's worked its way into a narrow area from which it's unable to escape, it stops and beeps a mournful tone every minute or so to help its owner find it.
See also: Maxx, Domestic robot.