iRobot Roomba Comparison

iRobot Roomba Comparison

List of iRobot Roomba models

iRobot Roomba 521 531 555 564 581 770 780
Price (£) £214.99 £234.99 £284.99 £329.99 £339.00 £379.99 £465.99
On-Board Scheduling

Virtual Walls 0 1 1 2 0 1 0
Virtual Wall Lighthouses 0 0 0 0 3 0 2
Brush Cleaning Tool 0 1 0 2 1 1 1
Replacement Brushes Kit

Extra Filters 1 1 1 2 1 2 2
AeroVac Vacuum

High Capacity Bin

Wireless Command Centre

AeroVac™ Series 2 Bin

Full Bin Indicator

IR Remote Control

Persistent Pass Cleaning

Package weight 6.12 kg 5.47 kg
6.12 kg 6.25 kg 6.58 kg 6.3 kg 6.5 kg
HEPA Filters


All Roomba models are disc-shaped, 34 cm (13.4") in diameter and less than 9 cm (3.5") high. A large contact-sensing bumper is mounted on the front half of the unit, with an omnidirectional infra-red sensor at its top front center. A carrying handle is fitted on the top of most units.

As of 2011, there have been three generations of Roomba units: the first-generation original models, the second-generation "Discovery" series; and the newest third-generation 500/600/700 Series.

All versions of the Roomba utilize a pair of brushes, rotating in opposite directions, to pick up debris from the floor. In most models, the brushes are then followed by a squeegee vacuum, by which the airflow is directed through a narrow slit to increase its velocity, in order to collect fine dust. A horizontally-mounted brush on the right side of the unit sweeps against walls to reach debris not accessible by the main brushes and vacuum. In the first generation of robots, the dirty air passes through the fan before reaching the filter, while later models use a fan-bypass vacuum.

The Roomba operates with internal nickel-metal hydride batteries (NiMH) and must be recharged regularly from a wall plug, although newer second and third-generation models have a self-charging homebase they automatically try to find (via its infrared beacons). Charging on the homebase takes about three hours. All second and most third-generation Roombas can be used with the homebase, even if they do not come packaged with it. First and second-generation models came packaged with a twelve-hour "standard" charger, although an optional 2.7-hour Rapid Charger was sold by iRobot to charge batteries externally from the robot. Third-generation Roombas use internal batteries not intended to be routinely swapped.

Four infra-red "cliff sensors" on the bottom of the Roomba's bumper prevent it from falling off ledges such as the top steps of stairways. Most second- and third-generation models have internal acoustic-based dirt sensors that allow them to detect particularly dirty spots (zones having excess particulates) and focus on those areas accordingly. Many second- and third -generation Roombas come packaged with IR (infrared) remote controls, allowing a human operator to "drive" the robot to areas to be specially cleaned.

Some 500 series robots also include "Virtual Wall Lighthouses". These radio-frequency transmitter/receiver for use with Virtual Wall Lighthouses, which are explained in the next section of this article. This feature is now only available on the higher end 500 and 700 series robots.

iRobot has released several types of dust and debris collection bins for the 500 Series robots. The standard "Vacuum Bin" incorporates the separate squeegee vacuum, as with all prior models. The "High Capacity Sweeper Bin" does not include a vacuum, but has greater capacity for debris collected by the brushes. The "Aerovac Bin" directs suction airflow through the main brushes instead of using a squeegee.


All Roomba models can be operated by manually carrying them to the room to be cleaned, and pressing the appropriate button. First-generation models needed to be told the size of the room via three room size buttons (Small, Medium, and Large), but this is no longer required with later models, which automatically estimate room size and adjust cleaning time accordingly.

Second- or third-generation Roombas introduced several new operating modes. "Clean" mode is the normal cleaning program, starting in a spiral and then following a wall, until the room is determined to be clean. "Spot" mode cleans a small area, using a spiral pattern. "Max" runs the standard cleaning algorithm until the battery is depleted. "Dock" mode, introduced with the third generation, instructs the robot to seek a self-charging Home base and recharge itself. The availability of the modes varies depending on model, generally with higher-end units having more features.

A second generation Roomba may also be used with the external Scheduler accessory. It allows the Roomba to begin cleaning automatically at the time of day that the owner desires. This can be useful for people who want the Roomba to clean while they are at work. Most 500 Series robots support scheduling through buttons on the unit itself, and higher-end models allow the use of a radio-frequency remote to program schedules.

The robot's bumper detects bumping into walls and furniture, and the Virtual Wall accessories project infra-red light beams which the Roomba will not cross. Special Scheduler Virtual Walls can be programmed to turn on at the same time a Scheduler-enabled Roomba is activated. This is desirable since the Virtual Walls are battery-powered, to avoid wasting power projecting IR beams when they are not needed.

Unlike the Electrolux Trilobite vacuuming robots, Roombas do not map out the rooms they are cleaning. Instead, they rely on a few simple algorithms such as spiral cleaning (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 as long to do the job as a person would. The Roomba may cover some areas many times, and other areas only once or twice.

After a sufficient period of time cleaning, the Roomba will stop and sing a few triumphant notes. The cleaning time depends on room size and, for newer models equipped with acoustic dirt sensors, volume of dirt. First-generation models must be told the room size, while second- and third-generation models estimate room size by measuring the longest straight-line run they can perform without bumping into an object. After cleaning, if a home base is detected, a second or third-generation Roomba will try to return to it. While docked with the home base, a Roomba will charge its battery. With the exception of the first-generation Roomba, an infrared remote control can also be used to control the unit, which is useful for a disabled person, or for manually directing the device to specific areas to be cleaned.

General maintenance of the robot consists of emptying the debris bin and cleaning the filter, as well as cleaning the brushes. Excessive hair accumulation in the brush system can cause the brushes to stall and/or overheat the brush motor, damaging the unit.

The Roomba is not designed for deep-pile carpet. The first- and second-generation Roombas would get stuck on rug tassels (though they could be tucked under before operating a Roomba) and electrical cords. The third generation is able to reverse its brushes to escape entangled cords and tassels. Roombas are designed to be low enough to go under a bed or other furniture. If at any time the unit senses that it has become stuck, no longer senses the floor beneath it, or it decides that it has worked its way into a narrow area from which it is unable to escape, it stops and sounds an error to help its owner find it.

The third-generation Roomba, which moves faster than previous Roombas, has additional forward-looking infrared sensors in its bumper to detect obstacles. The robot then slows down when nearing obstacles to reduce its force of impact.

First generation

Introduced in 2002, the first-generation Roomba had three buttons for room size. The first generation units comprise 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 use the same overall core robot and cleaning system.

400 series

The second-generation Roombas (dubbed "Discovery", later called "400 series") replaced their predecessors in July 2004, adding a larger dust bin, better software that calculates room sizes, dirt detection, and fast charging in the home base (or wall hanger, for the Discovery SE). All second-generation Roombas are functionally identical, though some have more or fewer buttons, accessories, or different external designs. A version with updated software and a new front wheel, "2.1" was issued in 2005, and the update was made available to existing units as well. The low-end models continued to be available after the introduction of the 500-series with new, three-digit model names.

Roomba budget models (Dirt Dog and Model 401) have a simplified interface (a single "Clean" button) and lack some of the software-controlled flexibility of other versions. They are positioned to be less expensive versions of the Roomba for first-time purchasers. The Roomba Dirt Dog contains sweeping brushes and a larger dust bin, but lacks the vacuum motor. It uses the space that would be required for the vacuum for additional dust bin volume. It was designed for home shop or home garage environments. The Roomba Model 401 is similar but has a 'standard' size dust bin and vacuum system. The budget models are compatible with the extended-life batteries, fast charger and schedulers of the 400 series.

500 series

The third-generation 500 series Roomba was first introduced in August 200, and features a forward-looking infrared sensor to detect obstacles and reduce speed, a dock button, and improved mechanical components. It also introduced customizable face plates.[1] For example, the Roomba 530 came with two virtual walls and a recharging dock The 500-series/3rd gen. worked more smoothly than the previous models.

700 series

In January 2011, iRobot announced the Roomba 700 Series robot. Although largely similar to the 500 Series robots, the 700 series features a more robust cleaning system and improved battery life, among other small improvements. The robot began shipping in spring 2011.

The Roomba 770 adds new internals as well as a HEPA filter and a double capacity bin. The updated robotic vacuum started shipping in May 2011.


  • Easy Clean Brush — A brush that is designed specifically for cleaning pet hair, being easier to clean off (standard on models designated "for pets").
  • Remote Control — Allows the owner to control the Roomba remotely (works with all second- and third-generation Roombas).
  • iRobot Scheduler — Allows the owner to program the Roomba to clean at certain times automatically. The "Schedule Upgrade" accessory will also update a pre-2.1 Roomba to the 2.1 software (for second-generation Roombas).
  • Homebase — The Roomba automatically returns to and docks here for recharging (for second- and third-generation Roombas).
  • Virtual Wall — Used for keeping the Roomba out of designated areas.
  • Virtual Wall Lighthouse — Functionality of Virtual Wall with an additional 'Lighthouse' mode, which will contain Roomba in one room until the room is completely vacuumed before moving on to the next.
  • OSMO — A dongle that attaches to the serial port on the Roomba. This updates a pre-2.1 Roomba's firmware to version 2.1 and can also correct the "circle dance" problem (for all second-generation Roombas).
  • Advanced Power System (APS) Battery — Higher-performance rechargeable battery for all Roomba models that holds enough power to clean for 200 minutes.
  • Roomba Serial Control Interface (Roomba SCI) — exposes all the functionalities and sensor information from the iRobot Roomba vacuum cleaner. Using the Roomba SCI, a roboticist can command and control the Roomba by interfacing to the 7pin Mini Din UART port.
  • Roo series of accessories, by RoboDynamics
    • RooTooth — A Bluetooth module that converts the Roomba to Bluetooth control from any bluetooth device.
    • RooStick — Allows programming input through a USB interface.
    • Roo232 — Allows programming input through a serial port connector.
  • RoombaFX — A C# class by RoboDynamics that implements the entire Roomba SCI command set. Available on Source Forge for download and user contributions.

Hacking and extending Roomba

From the earliest models on, Roomba vacuum cleaning robots have been hacked to extend their functionality. The first adaptations were based on a micro controller that was directly connected to the motor drivers and sensors of the original Roomba. Versions of the Roomba manufactured after October 2005 contain an electronic and software interface that allows hackers to control or modify Roomba’s behavior and remotely monitor its sensors more easily.

The Roombas with an interface (400 series models from after October 2005 and newer series like 500 and 700) come with a Mini-DIN connector supporting a TTL serial interface, which is incompatible with standard PC/Mac serial ports and cables, both electrically and physically. However, third-party adapters are available to access the Roomba's computer via Bluetooth, USB, or RS-232 (PC/Mac serial). Roombas from after October 2005 upgraded with the OSMO hacker device allow the user to monitor Roomba's many sensors and to modify its behavior. The Roomba Open Interface (formerly "Roomba Serial Command Interface") API allows programmers and roboticists to create their own enhancements to Roomba. Several projects are described on Roomba hacking sites.

In response to the growing interest of hackers in their product, the company developed the iRobot Create. In this model the vacuum cleaner motor is replaced by a "cargo bay" for mounting devices like TV cameras, lasers and other robotic parts. The Create provides a greatly enhanced, 25-pin interface providing both analog and digital bidirectional communication with the hosted device. Thus, it can then be used as the mobile base for completely new robots. Together with a computing platform like a netbook or handheld device with wireless networking capacity, it can be remotely controlled through a network.