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Do robot vacuums work on black carpet?
Updated
Some do and some do not, and listings almost never tell you. The sensors that stop a robot from falling down stairs can read a black or very dark floor as an edge. The robot then backs away or stops. If you have black carpet or a rug with wide black stripes, buy from a store with easy returns and try it in the first week.
Why it happens
Cliff sensors sit under the front edge of the robot. On most robots each one shines infrared light down and looks for it to bounce back. At the top of a staircase nothing bounces back, so the robot turns away. A black surface soaks up much of that light, so to the sensor it can look the same as a drop.
What iRobot says about its own robots
- iRobot's support page lists the series that "may not run on certain dark or black colored surfaces". The list includes the 100 series. The Roomba 105 Vac carries a 100 series model number, so we read that as covering it.
- For those models it says the robot may ask to be moved or back away, and that there is no adjustment that corrects this.
- It says some of its higher series do better on dark floors, and that even those can still trigger a cliff sensor.
- It says not to block or disable the cliff sensors, because that can create an unsafe operating condition.
What we saw on the other listings
Nothing. The roborock Q10 S5+, roborock Qrevo S Pro, Shark AI Ultra and eufy 11S MAX listings do not mention dark floors that we saw. The eufy names drop-sensing and the Roomba names sensors that prevent falls down stairs. Any robot with drop sensors can have this problem. We cannot tell you which of them cross black carpet, because we have not run them and the makers do not say.
How to check in week one
- Wipe the cliff sensors with a clean dry cloth first. iRobot notes that dust on the sensors causes the same fault.
- Start the robot next to the dark area in good light and watch. Backing away from the edge of the rug, or stopping with a "move me" message, is the sign.
- Try the darkest spot in the house, not the average one. Black borders and stripes on a lighter rug count.
- If it fails, return it or set the rug as a keep-out zone in the app. A robot with no map, like the eufy, cannot do that.
Do not tape over the sensors
You will find that tip online. It turns off the thing that keeps the robot from driving off your stairs. If your home has any stairs, steps or a sunken room, leave the sensors alone.
A dark room is a different question from a dark floor. See robot vacuums in the dark. For the picks, go to the roundup, and for upkeep, the emptying calculator.