Today’s Xiaomi and Roborock robot vacuum cleaners are sophisticated navigation systems that rely on the accuracy of multiple sensors. When a device starts to stumble upon obstacles, fall down stairs, or lose a map of a room, the problem most often lies not in software failure, but in the banal contamination of optics. Dust, animal hair and fat plaque accumulate over time on the surface of the sensors, blocking infrared radiation and distorting lidar data.
Regular maintenance of optical systems is key to a long and efficient work of your smart assistant. In this article, we will discuss in detail where key sensors are located, how to wipe them safely and how to avoid typical errors in maintenance of equipment. Sensor hygiene directly affects the quality of mapping and the ability of the robot to clean in hard-to-reach places.
Before you start cleaning, it's important to understand that there are complex electronics inside the enclosure. Careless handling of detergents or the use of aggressive chemicals can permanently disable expensive navigation modules. We'll look at proven methods that service engineers use to restore the positioning accuracy of the robot.
Types of navigation sensors and their location
To clean effectively, you need to know what we're dealing with. Roborock's vacuum cleaners are equipped with multiple groups of sensors, each of which performs a different function. The main element of navigation is LiDAR, a laser rangefinder located in a characteristic "drum" on the top of the housing, which scans the room and builds a map.
The second critical unit is the elevation drop sensors, often called "fall sensors," which are located around the perimeter of the bottom of the device and prevent the robot from falling from steps or thresholds, and there are collision sensors ( bumpers) and carpet detection sensors, which are often confused with navigation sensors, although the principle of their operation may differ.
The third group is optical sensors on the bottom that help the robot navigate the surface and track distance traveled, and contamination of any of these elements leads to specific errors, such as if only LiDAR is dirty, the robot will spin in place, and if the fall sensors are contaminated, it may refuse to go to dark mats or, conversely, try to move off the sofa.
Technical nuances of LiDAR work
Necessary tools and preparation for cleaning
Before the procedure begins, you need to prepare the workspace and tools. You don't need complex equipment, but using the right materials is critical to preserving the anti-reflective coating of the lenses. The main tool is a soft, lilaless fabric made of microfiber, like the one used to wipe smartphone screens or glasses.
Alcohol, acetone, ammonia-based wipers or abrasive powders are not allowed as cleaning liquids, and these substances can damage plastic and optical coatings, distilled water or specialized sprays for optics cleaning are the best solution, and you will need a dry soft brush (for example, for makeup or drawing) and possibly a can of compressed air.
⚠️ Warning: Never spray liquid directly onto sensors or the body of a robot. The liquid can leak into the body and cause a short circuit. Always apply the product to a fabric or cotton swab.
The preparation of the device is to turn it off completely, not just send it to base, but turn it off by pressing the power button for a long time or remove the battery, if the model allows it to do this easily, and it will protect the electronics from accidental voltage surges when contacted with wet fabric.
☑️ Preparation for cleaning
Cleaning of the main laser module (LiDAR)
The most important and often polluted element is the LiDAR tower on the top panel, inside a transparent or tinted dome, there's a rotating mirror and a laser emitter, and over time, fine dust settles on the inner and outer walls of the dome, which, when the fan is running, is sucked into the module.
To clean the outer surface, you need to gently wipe the dome with a slightly damp microfiber in circular motions. If you notice dust inside the transparent cap, it can be carefully removed (on some models it is held on latches or friction-fit, on others it is part of the body). Once you remove the protection, you will have access to the rotating mechanism. Clean the mirror and lens with a dry soft brush, sweeping away the dust with light movements.
The laser emitter and receiver require special delicacy. Do not rub them with effort. If the dust dries, use a slightly moistened cotton swab, but make sure that the pile does not remain on the lens. After cleaning, be sure to let the module dry for 5-10 minutes before assembly.
| Type of pollution | Symptoms. | Cleaning method |
|---|---|---|
| Dust on the outer dome | The robot sees obstacles where there are none. | Dry microfiber |
| Fat plaque | Reducing the range of the laser | Microfiber with distilled water |
| Wool inside the module | Extraneous noise, humming, map errors | Dry brush, tweezers |
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If after cleaning LiDAR, the robot continues to issue the error "Lidar Tower is locked", check whether the long coat or threads are wound on the engine axis inside the tower.
Maintenance of elevation sensors
The drop sensors are on the bottom panel of the robot, usually four or six, and they look like little black windows that are deep in the body, and their job is to read the reflection of the infrared beam from the floor, and if the floor is dark or the sensor is contaminated, the beam is not reflected, and the robot thinks there's a cliff ahead.
Cleaning these sensors often solves the problem when the robot refuses to go to dark mats or constantly writes the error "Raise the elevation sensors." Wipe each "window" with a dry cotton swab, removing the layer of dust. Pay special attention to the edges of the recess, where often piles accumulate.
Sometimes the problem is not the dirt, but the surface characteristics. Black glossy floors or very dark carpets can absorb infrared radiation. In such cases, cleaning will not help, and you will have to use special magnetic tapes or seal sensors (the "crutches" method), but this is already a last resort. First of all, make sure that the sensor glass is crystal clear.
Collision sensors and wheel sensors
The front of the robot is equipped with a mechanical bumper, behind which are infrared collision sensors, which help the robot gently touch the furniture and turn around. If these sensors are contaminated, the robot can either ignore the obstacles by ramming them, or "phantomly" feel the wall in the void.
Clean the bumper area by wiping the gap between the movable and the stationary parts of the body, often stuffed with dust that blocks the bumper itself or blocks the view of the sensor, and also check the side sensors, if any in your model Roborock.
Special attention should be paid to sensors on wheels. In modern models, optical encoders are located inside the wheel niches that track the rotation of the wheel. If a dense lump of wool is filled there, the robot will lose orientation in space and will spin in place, reporting a stuck position.
⚠️ Warning: When cleaning wheel niches, be careful with the brush. Do not damage the thin wires that go to the motor wheels, and do not use metal objects to pick dirt.
Removing Common Errors After Cleaning
Once you have cleaned the sensors completely, you need to start the device correctly, turn on the robot vacuum cleaner and let it complete the procedure (self-check). If there are any errors, try restarting the device completely.
Often, the sensors are clean, but the robot has old data or a map of artifacts in its memory, so it's useful to clear the map of the room through the Mi Home or Roborock app and start building a new one, so that the system can recalibrate the sensor readings in a clean state.
If the robot continues to behave inadequately, check if you accidentally pasted the sensors with a protective film when you bought it and forgot to remove it. Also make sure that there is enough light in the room to operate the optical sensors (although LiDAR works in the dark, other sensors may require light).
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90 percent of navigation and robot behavior problems are solved by simply wiping your sensors with a dry cloth. Don't rush to bring the device into service until you've done this.
Prevention and frequency of service
How often do you need to clean the sensors? It depends on the operating conditions. In an apartment where molting animals live, optics and LiDAR are cleaned every 1-2 weeks. If you do not have animals and carpets, you just need to do this once a month when replacing the dust collector.
Regular wet cleaning in the house also prolongs the life of sensors, as it reduces the amount of flying dust. However, remember that the robot vacuum cleaner is not designed to clean water, so make sure that it does not drive on wet areas of the floor, which can splash the lower sensors.
Timely replacement of consumables, such as side brushes, also affects the purity of the sensors. An old, disheveled brush can scatter dust to the sides, settling on the optics, instead of collecting it.