Modern robot vacuum cleaners from Xiaomi and sub-brands like Roborock or Viomi are complex navigation systems that depend entirely on the purity of their sensory eyes. When a device starts to rush around the room, get stuck in a flat place, or worst of all, fall off the doorsteps, the problem is often not the breakdown of electronics, but the banal contamination of optical elements.
Smart tech owners often underestimate the importance of regular sensor care by relying on a powerful suction system. But optical sensors are responsible for mapping and driving safety. Dust, pet hair, and small debris eventually form a dense film on the lenses, distorting the data the robot receives about its surroundings, leading to logical errors in the navigation algorithms.
In this article, we will take a closer look at where the sensors are located on different models, what tools will be required for delicate cleaning, and how to interpret the error beeps correctly. You will learn to distinguish between a software failure and a physical sensor lock, which will save time on calling the wizard and prolong the life of your gadget.
Symptoms of Navigation Sensors Contamination
The first sign that the robot's optical system needs intervention is a change in the pattern of motion, so the device can start to make sharp, unreasonable turns, or, conversely, persistently ram the legs of chairs that it has previously successfully bypassed, because the infrared rays emitted by the transmitter are scattered on the dust layer and do not return to the receiver at the desired intensity.
Another alarming sign is frequent getting stuck on low-pile carpets or trying to fall off the carpet, although the elevation difference is minimal. In such cases, the robot mistakenly interprets the dark surface or the accumulation of dust under the bottom as a cliff, the safety system activates the drop-prevention mode, and the cleaning stops.
Pay attention to the lights on the case or notifications in the Mi Home app. Many models report specific sensor issues, although users often ignore these messages as a temporary glitch.
- 🚫 The robot constantly reports an error “fall sensor” or emits a corresponding sound signal when moving on the floor.
- 🌀 The device randomly rotates in one place, unable to build the correct route.
- 📉 A noticeable decrease in the efficiency of cleaning along the walls due to incorrect operation of the side distance sensor.
It is important to understand that ignoring these symptoms can lead to more serious consequences: constant hits on furniture damage the bumper and mechanical switches, and attempts to overcome non-existent obstacles wear out the motor wheel.
Necessary tools for maintenance
Before you start maintenance, you need to prepare the right arsenal of tools, use of aggressive chemicals or rough materials can irrevocably damage optical lenses and plastic sensor cases, and you need a minimum set of tools that you can find in your home.
The main tool will be a lilac wipe made of microfiber or special wipes for monitor screens. Conventional paper towels or cotton-coated discs can leave a small pile, which later falls back into the mechanism or sticks on the lens, making the situation worse.
⚠️ Attention: Alcohol-containing solvents, acetone or window washing products directly on the surface of sensors are strictly prohibited. Aggressive chemistry can cause plastic to cloud or destroy the anti-reflective coating.
To remove dust from hard-to-reach areas, a compressed air can or a pear for cleaning the optics is ideal, and a soft brush with a natural pile may also be needed to gently sweep the contamination from the crevices around the sensors without scratching the surface.
💡
If you do not have a special liquid for optics, slightly moisten the microfiber with distilled water. The main thing is that the fabric should be only slightly moist so that the drops do not leak into the body.
Location of sensors on different models
Xiaomi's robot vacuum cleaners have evolved from generation to generation, and the location of the sensors can vary significantly. Understanding your device's architecture is key to successful cleaning. Older models with gyroscopic navigation have focused on bottom sensors, while modern laser models have a whole range of perimeter sensors.
Below is a table that helps identify the main types of sensors and their location on the case:
| Type of sensor | Location. | Function | Frequency of pollution |
|---|---|---|---|
| Fall sensors (Cliff) | Bottom panel, closer to the edges | Preventing falling from height | Tall. |
| Collision sensor (Bumper) | Front movable part | Responding to contact with objects | Medium |
| Optical flow sensor | The bottom, next to the brush. | Determination of distance travelled | Critical |
| Wall sensor | Side of the body (not on all models) | Traffic along the walls | Low. |
Special attention should be paid to the optical flow sensor, which is often confused with a conventional fall sensor, located on the bottom and works like an optical mouse, reading the texture of the floor. If a stain forms on its lens, the robot can "lost" and begin to build the wrong map of the room.
Laser rangefinder (LDS) models on top also have additional windows through which the laser passes, but they are less likely to become contaminated by the protective dome, but if the robot is working in a dusty room, dust can also settle on the horizontal surface of the laser, which requires careful purge.
Hidden sensors
Step-by-step instructions for cleaning
The cleaning process requires consistency and precision, first you have to turn the device off completely and turn it upside down, and then you put the robot on a soft surface, like a towel, so you don't scratch the top cover or the touchpad.
Start with the bottom panel. Clean all the holes where the drop sensors are located carefully. The movements should be circular, but without strong pressure. If you see the swelling dirt, use a slightly damp napkin, and then immediately dry.
☑️ Checklist for cleaning
Pay special attention to the area around the main brush, and often this is where the hair and dust cocoon accumulates, which partially obscures the view of the lower sensors, and use tweezers or scissors to remove these lumps before rubbing.
After processing the bottom, move to the front of the body, gently wipe the transparent or black window of the impact sensor, and remember the side edges if your model is equipped with a side sensor.
⚠️ Warning: Never use sharp objects, such as needles or toothpicks, to pick dirt directly into the sensor hole.You can scratch the lens from the inside or damage the sensitive element itself.
The final step is to blow all the holes out with a jet of air, which will remove the microscopic dust particles that may have been left behind after wet cleaning, which are not visible to the eye, but capable of working the IR emitter.
Diagnostics and performance verification
Once you've done all the manipulations, you need to make sure that you're working effectively, put the robot on and start cleaning mode, and watch the first minutes of operation, and the device needs to move forward with confidence, without making false turns.
You can use the Mi Home app to do a deeper check, and the robot's settings section often includes a sensor status check or error log, and some advanced users use debugging mode, which displays real-time sensor readings.
- 👁️ Raise your hand to the lower drop sensors on the working robot – it must react with a stop or an audible signal, “thinking” that this is the edge of the table.
- 🛑 Easy press on the front bumper – the robot must pull back, fixing the obstacle.
- 🗺️ Start building the map on a familiar area - the trajectory should be flat, without sharp zigzags.
If the robot continues to behave strangely, it may not be the pollution that is the problem, but the hardware malfunction, but 90 percent of the time, a thorough cleaning restores the device's vision.
💡
Regular preventive cleaning of sensors every two weeks avoids 95% of navigation problems and prolongs the life of a robotic vacuum cleaner.
Frequent errors in service
Even following instructions, users often make mistakes that negate all efforts, the most common being using excessive amounts of moisture, and water entering the housing through sensor holes can cause the control board to short-circuit.
Another mistake is ignoring the charge sensor, and charging contacts also require cleaning, because oxidation or dust on them causes the robot to be unable to get back on base or report a charging error, even though the problem is trivial.
Removing the bottom cover to access the sensors often results in loss of warranty and disruption of gyro calibration. External cleaning is sufficient in most cases.