A Roomba is an autonomous robotic vacuum cleaner made by the company iRobot, and was first introduced in September 2002. Roombas have a set of sensors which help them navigate the floor area of a home. These sensors can detect the presence of obstacles and steep drops (e.g., to avoid falling down stairs).
As of 2024, iRobot markets models of their fourth through tenth generation, while continuing to provide support and to sell accessories for their previous series. Various models of the Roomba have different features, including tangle-free brushes, separate sweep canisters, more powerful vacuums, mopping technology, obstacle avoidance, and performance maps displayed via smartphone apps. Newer models also have a camera, which works in conjunction with onboard mapping and navigation software to systematically cover all floor areas, move from room to room, avoid obstacles such as pet waste and charging cables, and find charging stations.
History Engineer Joe Jones first conceived the idea for what eventually became the Roomba in 1989 while working at the MIT Computer Science and Artificial Intelligence Laboratory. The initial design, using LEGO bricks, stemmed from a design challenge between Jones and his colleagues. Early prototypes were created and presented to the Denning Mobile Robot Company and Bissell in the 1990s, but neither company was interested in producing them. The concept languished until 1999, when S.C. Johnson eventually agreed to fund the project at iRobot. The device was initially called "DustPuppy" before being renamed to Roomba. Development began in full in December 1999. S.C. Johnson pulled out after spending US$1–2 million, but iRobot continued with the project, eventually launching the first Roomba in September 2002.
Design
Roomba models are designed to be low enough to fit under beds or other furniture. Most Roomba models are disc-shaped, measuring in diameter and in height depending on the model. The S9 series robots are semicircular rather than circular, with a flat part at the front, and are narrower at wide. All models feature a large contact-sensing mechanical bumper on the front half, with a multi-directional infrared sensor located at the top front center. Most models also have a recessed handle located on the top.
The first and second-generation Roomba models utilized the Virtual Wall, a separately sold accessory that prevents it from entering an area. It projects a pattern of infrared light, which the vacuum detects and treats as a physical wall, prompting it to stop and turn around. However, third-generation and newer models have now been made compatible with the Dual Mode Virtual Wall, which, in addition to simulating a straight wall, can create a circular barrier roughly in diameter. Some 500, 700, and 800 series models are compatible with the Virtual Wall Lighthouse. It initially confines the vacuum to one area to be cleaned. Once the vacuum reports the area being sufficiently cleaned (based on its estimated area), it directs it to proceed to the next space to be cleaned and contains it there.
A Roomba's bumper allows it to sense when it has bumped into an obstacle, after which it will reverse or change paths. Infrared "cliff sensors" on the bottom of the unit similarly prevent them from falling off ledges such as stairs. These may also trigger a false positive on dark or black-colored surfaces, such as some carpets, preventing Roombas from entering or cleaning those areas. Third-generation and newer models have additional forward-looking infrared sensors to detect obstacles. These sensors slow down the Roomba's speed when nearing obstacles to reduce its force of impact. It also cleans along walls without repeatedly bumping into them. This technology can also distinguish between hard and soft obstacles.
Most second- and third-generation models, as well as all newer ones, have internal acoustic-based dirt sensors that allow them to detect and focus on particularly dirty spots. Fourth-generation and newer models have an optical sensor located in front of the vacuum bin, allowing detection of wider and smaller messes.
Third-generation and newer models can reverse their brushes' rotation direction to escape entangled cords and tassels. If at any time the unit senses that it has become stuck, is unable to turn its main brushes, no longer senses the floor beneath it, or decides that it has worked its way into a narrow area from which it is unable to escape, it stops and sounds an error alert to help someone find it. Early models use only flashing lights or several beeps to indicate specific problems, while later models use a synthesized voice to announce a problem and a suggested solution.
Operation Control and cleaning
All Roomba models can be operated by manually carrying the Roomba to the room to be cleaned and pressing a button. Third-generation and later models can also be started directly from their charging bases. Later models introduced several additional operating modes, such as "spot", which cleans an area of a few feet. Older Roombas had a "max" mode, which cleans endlessly until the battery is depleted; this was replaced by "Clean" on later models that had the ability to calculate room size. "Dock" mode, introduced with the third generation, instructs the Roomba to seek a charging base for recharging. The availability of the modes varies by model. Many second- and third-generation Roombas and certain newer models (such as the 880), come packaged with infrared remote controls or special control panels, allowing a human operator to "drive" the Roomba to areas to be specially cleaned.
Subsequent Roomba models can be controlled with the iRobot HOME app, where users can start and pause the Roomba, send it back to the charging base, choose time limits for it to run before returning home, and view details about each cleaning job, such as how long the Roomba ran for and how the job ended (i.e., being completed, canceled or the battery dying).The cleaning time depends on room size and, for models equipped with dirt sensors, the volume of dirt. First-generation models must be told the room size, while subsequent models either estimate the room size by measuring the longest straight-line run they can perform without bumping into an object, or by creating a map of the room.
Non-desktop users can use the iRobot HOME App, although only certain models support 2.4 GHz. Wi-Fi connected Roombas can also connect to Alexa, Google Home, and other smart home platforms for voice control or use in automation.
Pathing
Starting with the sixth generation, Roombas have an upward-facing camera and a downward-facing infrared floor-tracking sensor, which are used to create a map of the floor. This enables them to use a back-and-forth cleaning pattern, which is faster and more efficient because it ensures more complete coverage without needing to cover an area multiple times. The floor-tracking sensor operates like an optical mouse and can provide precise movement data over small distances. However, this causes integration drift and small errors in measurement that accumulate over time. To rectify this, the upward-facing camera is used periodically to identify waypoints or "landmarks", coarse points that are used to correct the Roombas' position and map.
Roombas before the sixth generation models do not map out the rooms they are cleaning. Instead, iRobot developed a technology called iAdapt Responsive Cleaning Technology that relies on a few simple algorithms, such as spiraling, room crossing, wall following, and random walk angle changing after bumping into an object or wall. This design is based on MIT researcher and iRobot CTO Rodney Brooks' philosophy that robots should be like insects, equipped with simple control mechanisms tuned to their environments. The result is that, although Roombas are effective at cleaning rooms, they take several times longer to do the job than a human would. Some users have used long-exposure photography or compositing to create images showing Roombas' coverage of the floor, and have even attached light sources to Roombas to create art using light painting.
Some have also noted that doubts about the effectiveness of the random algorithms have been reinforced by multiple reports of Roombas rolling over dog feces and spreading them through the room, which rather unpleasantly illustrates how well the Roomba can cover the floor's area. Roombas have become a common example of how randomized algorithms can routinely succeed even though they cannot absolutely guarantee success on any single run or even after many repeated runs. Compared to competing products available when Roombas were first introduced, such as the Electrolux Trilobite, the effectiveness of Roombas' random navigation was on par with (or even more effective than) robotic mapping technology available at the time, and cheaper to develop and produce, meaning it was sold at a significantly lower price.
Models
there have been ten generations of Roomba units. All models have a patented design using pairs of brushes or rollers rotating in opposite directions to pick up debris from the floor.
The early-generation models use a random algorithm by "bumping" to achieve total room coverage. A small vacuum motor with the help of rotating brushes extract the debris into a removable dustbin. The robot moves around the room with two rubber wheels on the backside of the unit. Roomba's are equipped with several sensors, including inside the bumper mechanism. IR emitters and receivers are equipped inside the bumper to communicate with the Home Base or Clean Base during docking. These sensors also initiate the self emptying cycle (Clean Base only). An ultrasonic proximity sensor is also used to slow the Roomba down to minimize impact into walls. iRobot's patented "RCON" sensor is located on the top of the bumper. This sensor helps the Roomba avoid virtual walls and its home base and/or clean base. The robot is powered by a rechargeable battery contained inside the unit.
First generation: Original series
Introduced in September 2002, the first-generation Roomba had three buttons for room size. The first-generation units comprised the original silver-colored Roomba, the blue Roomba Pro, and the maroon Roomba Pro Elite. The latter two models included additional accessories, but all three used the same core robot and cleaning system.
An original Roomba model robotic vacuum is in the collection of the National Museum of American History, which they note as the first successful domestic robot. The robot vacuum is described as being able to change direction when it encounters an obstacle or infrared beam and is powered by a battery.
Second generation: Discovery and 400 series
The second-generation Roombas ("4000 series" later called the 400 series) replaced their predecessors in July 2004.
Roomba budget models (Dirt Dog and Model 401) used a simplified interface (a single "Clean" button) and lacked some of the software-controlled flexibility of other versions. They were less expensive models intended for first-time purchasers. The Roomba Dirt Dog contained sweeping brushes and a larger dust bin, but lacked the vacuum motor, using the space that would be required for the vacuum for additional dust bin volume. It was designed for a home shop or garage environment.
Third generation: Professional and 500/600 series