Do Roombas work?
In 1962, the futuristic family TV cartoon program “The Jetsons” (set in 2062, 100 years in the future) accurately predicted many of the technologies we use today. George Jetson and his family used video calls, tablet computers, flying cars, robotic house help and robotic vacuum cleaners.
Today we benefit from digital technology that has made our lives far easier and better, and the development of the intelligent vacuum cleaner is just one example.
One of the most capable machines is the iRobot Roomba. A miniature, computerized cleaner that not only travels around your house automatically vacuuming the floors, carpets and rugs, it also employs artificial intelligence to map out a room, identify obstacles and recall the most efficient routes for cleaning.
So, how does a Roomba accomplish those tasks automatically?
What is a Roomba?
The Roomba uses a mechanism to pick up dirt and small particles like a conventional vacuum cleaner. A side-mounted flailing brush pushes dirt underneath the machine, where two counter-rotating brushes pick up the dirt and guide it toward the powerful vacuum. The dirt and debris end up in a small storage bin.
Unlike a traditional vacuum cleaner, the Roomba is equipped with two large tractor-style wheels. A separate electric motor independently drives each wheel. Capable of rotating in opposite directions, the machine can turn in place and therefore clean nearly any space it can enter.
The onboard NiMH rechargeable battery pack provides power. The device is designed to consume minimal energy and run for long periods (as much as 90 minutes on some models) between charges.
How do Roomba sensors work?
The Roomba employs three types of sensors to navigate around the house: infrared sensors, photoelectric cells and a piezoelectric sensor.
Infrared sensor
Infrared (IR) light, or infrared waves, are part of the electromagnetic spectrum that occur at higher frequencies than microwaves and just lower than those of red visible light, for which they are called “infrared.” Not visible to humans but detectable as heat, typical infrared uses include night vision (detecting objects in dark environments) and changing channels with a TV remote control.
Photoelectric cell sensor
The photocell uses the photoelectric effect to convert light energy to electric energy. A photoelectric cell emits an infrared light beam from its light-emitting element toward a target or object. A reflective-type photoelectric sensor then detects the infrared beam that bounces off the target.
Roomba infrared sensors detect changes in motion, while the photocells measure changes in light levels. The infrared sensor positioned on the front of the device sends out a light beam that reflects off any obstacle. A photocell sensor reads the reflected light to determine an object’s presence and precisely measures its distance from the device.
Piezoelectric sensor
The Roomba is also fitted with a piezoelectric sensor consisting of a crystal placed between two metal plates. When mechanical pressure (like squeezing) is applied to the metal plates, an electrical potential (voltage) is produced.
A Roomba uses its piezoelectric sensor to detect the presence of excessive dirt and debris. When enough tiny dirt particles impact the sensor, electrical impulses trigger a built-in program, “Dirt Detect,” prompting the device to make a second pass over the same area for a more thorough cleaning.
Touch-sensitive bumper
While the infrared beam sensors detect walls and obstacles before the Roomba reaches them, the touch-sensitive bumper stops the device when it actually impacts anything. Other infrared sensors (Cliff Detect) mounted underneath point directly downward to warn the Roomba of stairs and steep drops, allowing the machine to clean close to the edge without tumbling down the stairs.
The machine also detects the presence of cables and carpet tassels lying on the floor and stops the brushes from rotating before they become entangled.
The entry-level Roomba 614 uses dual multiple-surface brushes that work on carpet and hardwood floors, and it comes equipped with basic sensors, including Cliff Detect. The device has an average battery life of 90 minutes.
Which cleaning patterns does the Roomba use?
Watching a Roomba in action, you might conclude the device is not being guided by any cleaning program but proceeds randomly based strictly on objects encountered.
Your conclusion would not be far off. However, the Roomba’s route is usually a combination of two main patterns: “wall following” and “random bounce.” During the first pattern, the Roomba moves around the room next to the walls while its side-mounted, flailing brush reaches into the corners. For the second pattern, the device cleans until it encounters an obstacle and then changes direction.
Early Roombas used several cleaning modes, including a pattern that sweeps across a room at full speed to clean large areas. Upon arrival, the vacuum spiraled outward to cover a large space. Multiple passes were made over particularly dirty areas while flashing a bright blue “Dirt Detect” light to advise any observers.
Some Roomba models are compatible with Virtual Wall Lighthouses, small standalone beacons that send out invisible, infrared beams to define limits. In lighthouse mode, the beams help the Roomba learn where one room ends and the other begins.
How does the Roomba map a home?
The Roomba 560 and other early iRobot models cleaned mostly using a random pattern, while today’s models use artificial intelligence to map a room, identify obstacles and determine the most efficient routes for cleaning.
Roomba 980, 960, i7, i7+, s9, and s9+ all have the Vision Simultaneous Localization and Mapping (VSLAM) program built-in.
These Roomba models use onboard infrared cameras to take snapshots of a room. Simultaneously, VSLAM dynamically accumulates information about where the Roomba has been and determines where it still needs to go.
The navigation system allows Roomba to clean in straight lines with one pass instead of covering the same part of a room multiple times. Roomba’s engineers estimate the map-building feature cuts cleaning time by about 20 percent over previous less intelligent models.
The Roomba i7 features the latest iAdapt 3.0 system allowing it to map up to 10 unique floor plans for multilevel homes, and the vacuum boasts 10 times the suction power of entry-level models.
Does the Roomba have a self-emptying bin?
Most robot vacuums come with a small bin capacity of about 0.6 liters. When the bin gets full, the vacuum will drag excess dirt all over your house. Several robot vacuum companies now offer self-emptying stations.
Shark IQ Robot R101 Robotic Vacuum includes a self-emptying base. Shark claims the bagless base holds up to 30 days of dirt and debris.
ECOVACS also makes a 30-day capacity auto-empty station compatible with the DEEBOT OZMO T8 and T8 AIVI vacuums.
The Roomba is also offered with a self-emptying station. The Clean Base is a combination of self-emptying bin and a charging stand that’s compatible with i-series vacuums.
The Roomba i7+ includes iRobot’s Automatic Dirt Disposal dock, which holds up to 60 days’ worth of dirt and debris when used daily.
Wireless connectivity
Newer Roomba models connect to the iRobot Cloud via the iRobot HOME app, enabling features such as Alexa and Google compatibility, modifying cleaning preferences, Push Notifications, scheduling and receiving Over the Air Software updates.
Jeffrey Harper is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.
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