Smart tech owners often face situations where the Roborock S5 Max suddenly starts acting strangely: crashes into obstacles, can’t find a base, or spins randomly in one place. Most often, such failures are caused by the banal contamination of sensors, which are the “eyes” of your device. Dust, pet hair and small villi can completely disorient a complex navigation system, turning a high-tech assistant into a useless gadget.
Regular maintenance of optical and laser modules is not just a recommendation, but a necessity for the stable operation of LDS and Cliff sensors algorithms. In this article, we will discuss in detail how to properly maintain each type of sensors, what tools to use and what to do categorically not to damage electronics.
Ignoring cleaning can cause the robot to ignore virtual walls or, worse, to fall down stairs if you don’t have physical barriers. Understanding how each sensor works will help you quickly diagnose the problem and return the device to its former accuracy.
Preparation for maintenance and necessary tools
Before you start a surgical intervention, you need to properly prepare the workplace and tools. Safety and cleanness of the process is key to success. You don't need a sophisticated professional tool, but using the wrong materials can cause irreparable harm to sensitive lenses.
First, make sure the robot is completely off. Rotate the device up to the bottom to access the bottom panel, but don't rush to disassemble the body. The main cleaning of the external sensors is done without opening the structure.
You will need the following items:
- 🧹 Dry cotton swabs (it is better to use those with a plastic base so that the pile does not get stuck).
- 💨 A container with compressed air for blowing dust from hard-to-reach places.
- 🧼 Microfibre without pile for cleaning external surfaces.
- 🔦 A flashlight (light of a smartphone) for visual check of the condition of the lenses.
⚠️ Attention: It is strictly forbidden to use wet wipes, alcohol or aggressive chemicals directly on the surface of optical sensors. The liquid can leak under the glass and cause oxidation of contacts or clouding of the lens from the inside.
Pay special attention to lighting. Work best in bright daylight or under a desk lamp, because many contaminants are transparent and visible only at a certain angle of incidence.
Laser rangefinder (LDS) maintenance
The centerpiece of the Xiaomi Roborock S5 Max’s navigation is a laser rangefinder located in the top turret, which maps the room and tracks the robot’s movements in real time, and if the module is contaminated, the map will be built with errors, and the robot can be lost in a familiar room.
And there's a small, circular window on the top of the turret, which is the output for the laser beam, and over time, it's deposited with a thin layer of dust that scatters the laser signal, reducing the range and accuracy of the scan, and it's enough to clean it with a dry microfiber in circular motions.
Inside the turret itself, under the protective cap, is a rotating mechanism with a mirror, and if you notice that the turret is making strange sounds or spinning in jerks, you may have got wool inside.
- 🌪️ Use a spray of compressed air to blow the insides of the turret through the vents.
- 👀 Visually check if there is nothing preventing the rotation of the laser head.
- 🚫 Do not try to disassemble the turret without soldering skills and special screwdrivers - this is a complex knot.
What if the LDS turret doesn’t move out?
The purity of the laser module directly affects the speed of map construction, and a contaminated sensor causes the robot's processor to process data longer, which increases the cleaning time.
Cleaning Optical Floor Sensors and Cliff Sensors
There are many holes and eyes on the bottom of the device, and these are the Cliff sensors and the Optical Flow Sensor, which are the most common reasons why a robot refuses to start or falls from rapids.
The elevation sensors are usually located around the perimeter of the bottom, they emit infrared down and measure the distance to the floor, and if they're stuck with a lump of dust or hair, the robot thinks it's above the cliff, and stops with an error.
An optical tracker, often called a mouse, is closer to the center or wheels, and it takes pictures of the texture of the floor at high speed to determine the distance traveled, and the mud on the sensor causes the robot to not know whether it is moving or standing still.
☑️ Checklist cleaning of lower sensors
For good cleaning, use a dry cotton swab, walk carefully through each sensor hole, removing visible contaminants, and then blow the holes with air to remove the remains of the pile.
⚠️ Warning: If the robot continues to produce sensor error after cleaning (a flashing indicator or voice message), check if the holes are sealed with tape or protective film, which is often forgotten to remove during the first installation.
Wall and bumper sensors
The side walls of the Roborock S5 Max are equipped with infrared sensors that help the robot navigate along walls and gently touch obstacles.The mechanical bumper also has its own collision sensors that can stick to dirt.
Often, the side sensors will form a plaque that the robot perceives as a wall, which can drive strictly parallel to a non-existent obstacle or avoid open space, wipe the side panels with a wet (but not wet) cloth, and then wipe dry with microfiber.
The mechanical bumper in the front should be pressed freely and returned to its original position, and if it is stiff, it may have been mud or wool in the gap.
- 🖐️ Press the bumper several times along the entire length, checking the uniformity of the stroke.
- 🧹 Carefully clean the gap between the bumper and the body dry brush.
- 💨 Blow the bumper joint with compressed air at an angle.
Remember that the infrared receivers on the bumper must be clean to correctly read signals from virtual walls or beacons (if they are used in your configuration).
Wheel sensors and side brush
Although the wheels and brushes are not sensors in the literal sense, their condition directly affects the readings of the motion sensors. If the wheel is full of hair, the robot may misjudge the path traveled, which will lead to dissynchronization with the map.
The mobile wheels are equipped with sensors that detect their rotation. The wool wound on the axle blocks the wheel, and the robot begins to report a mistake in the main wheel. Regularly remove the wheels (they easily leach) and clear the axle from the windings.
The side brush also has its mechanism, and if it's locked, the current sensors will report it to the app.
Clean running gear is the guarantee that the optical sensors of the floor will receive a correct picture of movement without jerks and slips.
Diagnosis and table of frequent errors
Understanding which sensor is responsible for which error code makes it much easier to diagnose: Mi Home or Roborock usually delivers a specific message, but sometimes it is too general.
Below is a table that helps to link the robot’s behavior to a particular contaminated node.
| Symptom/Error | Probable cause | What sensor to clean |
|---|---|---|
| The robot is spinning around. | Pollution of LDS or optical tracker | Laser turret, floor sensor |
| Falls from thresholds/steps | The height difference sensor is not working. | Cliff sensors (on the perimeter of the bottom) |
| Crashing into walls | Failure of bumper or side IR sensors | Front bumper, side sensors |
| Can't find the base. | Dirty IR receivers on the bumper | Front panel (black windows) |
If the problem persists after cleaning, it is possible that the sensor has physically failed or the plume inside the housing has moved away.
Prevention and program settings
To avoid cleaning, you can use the software features of the Roborock S5 Max. For example, the Safe Navigation mode or no-go zones help the robot avoid places with large accumulations of dust or wires where it can get dirty.
Check the app's cleaning logs regularly, and if you see the map becoming less accurate or the robot starting to make unnecessary loops, that's the first signal to be serviced.
And you also need to pay attention to the operating conditions, because if you have a lot of long-pile carpets in your house, the sensors will get dirty faster, and in such cases, the frequency of maintenance should be increased.
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Wipe the sensors with a dry cotton swab immediately after each cleaning, if the house is being repaired or molted by animals - it will take 30 seconds, but save you from navigation errors.
Compliance with simple hygiene rules for your robot will prolong its life and maintain high cleaning efficiency for many years.
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Regular cleaning of Cliff sensors and laser rangefinder is the only way to ensure that the robot does not fall down the stairs and lose the map of the room.