Xiaomi’s robot vacuum cleaners are complex devices equipped with multiple sensors to navigate and avoid collisions. One of the key elements of the system is the obstacle sensor, which is responsible for detecting furniture, walls and other objects in the path. However, many users face difficulties in finding this sensor — especially when it requires cleaning, replacing or diagnosing malfunctions.
In this article, we’ll look at where the obstacle sensor is located in popular Xiaomi robot vacuum cleaners (including Mi Robot Vacuum, Viomi and Dreame), how it works, and what to do if the device has stopped “seeing” obstacles, and how to distinguish the obstacle sensor from other sensors (for example, from a drop sensor or a laser rangefinder) and what tools you will need to check it.
How to avoid obstacles in robot vacuum cleaners Xiaomi
Before looking for a sensor physically, it is important to understand how the entire navigation system works. Most Xiaomi models use a combination of several types of sensors:
- 🔴 Infrared (IR) sensors - detect objects at a close distance (5-30 cm.
- 🔵 Ultrasonic sensors – detect obstacles at a distance of 1-2 meters (used in premium models, for example, Xiaomi Mi Robot Vacuum-Mop 2 Pro).
- 🟢 Laser rangefinder (LDS) — Scans the room to build a map (not an obstacle sensor, but helps in navigation).
- ⚫ Fall sensors – prevent falling from stairs (located on the bottom panel).
In budget models (for example, Mi Robot Vacuum) 1S viomi V2) Usually only IR sensors are installed, whereas flagships (for example, DreameBot) are installed. Z10 Pro) adds ultrasonic sensors to more accurately detect objects, and the classical obstacle sensor is the IR sensor on the front bumper of the robot.
The way the system works is that when the robot approaches an obstacle, the IR sensor sends a signal to the processor, which instantly corrects the trajectory, and if the sensor is contaminated or damaged, the vacuum cleaner can beat furniture or "not notice" objects.
Where is the obstacle sensor: diagrams and photos for popular models
The location of the sensor depends on the model of the robot, and below are the diagrams for the most common Xiaomi devices.
1. Xiaomi Mi Robot Vacuum 1S / 2C / 2 Pro
These models use a bumper with integrated IR sensors, and the sensors are placed under a transparent plastic panel on the front of the body (see photo), with a total of 4-6 pieces (depending on the modification): 2-3 on each side of the center button.
To access the sensors:
- Remove the top cover (unscrewing 4 screws on the bottom panel).
- Carefully disconnect the bumper by snapping the latches on the sides.
- Under the transparent panel, you'll see small black or silver sensors -- these are infrared sensors.
2. Viomi V2 / V3 / SE
Viomi robots have similarly placed obstacle sensors, but can reach up to 8 (4 on each side), a feature that is often covered by an additional protective film that must be carefully removed during cleaning.
3. DreameBot D9 / Z10 Pro / L10 Pro
The premium Dreame models use ultrasonic sensors on the top of the body (on the sides of the laser rangefinder), but there are fewer IR sensors, usually 2-4, and they are hidden deeper under the bumper.
| Model | Type of sensor | Number of | Location. |
|---|---|---|---|
| Mi Robot Vacuum 1S | ICU | 4–6 | Under the front bumper |
| Viomi V3 | ICU | 8 | Under the bumper, with a protective film. |
| DreameBot Z10 Pro | ICU + ultrasound | 2-4 (IR) + 2 (ultrasound) | IR - under the bumper, ultrasound - on the top panel |
| Mi Robot Vacuum-Mop 2 Pro | ICU + laser | 6 (IR) | Under the bumper, next to the laser module. |
If your model is not listed in the table, focus on the general principle: IR sensors are always under the front bumper, and ultrasonic (if any) – on the top or side panel.
How to distinguish an obstacle sensor from a drop sensor?
Signs of failure of the obstacle sensor
If the obstacle sensor fails or becomes contaminated, the robot vacuum cleaner begins to behave inadequately.
- 🚨 The robot hits furniture, although it used to bypass it.
- 🔄 Often unfolds in place for no apparent reason.
- 🐢 It moves too slowly, as if it were "feeling" the way.
- 📛 Mi Home Apps Have Sensor Error (05) or Obstacle Sensor Fault.
- 🔦 The laser rangefinder works, but the robot does not respond to small objects (such as wires or chair legs).
⚠️ Attention: If the robot stopped seeing obstacles after a fall or a heavy impact, the problem may not be in the sensor, but in damage to the control board.
Most often, sensor contamination (dust, animal hair, greasy prints) is the cause of a malfunction, less often mechanical damage or contact dumping, and before you bring the device to the service, try cleaning the sensors yourself.
How to Clean the Obstacle Sensor: Step-by-step instructions
Cleaning the sensors is a simple procedure that can make the robot work again.
- 🧴 Cotton swabs.
- 💧 Alcohol (isopropyl or medical).
- 🔧 Plastic blade (to remove the bumper).
- 🕯️ Fen (for drying).
Turn off the robot and remove the battery
Remove the top cover (unscrew the screws)
Disconnect the front bumper (carefully, without effort!)
Wipe the sensors with alcohol without pressing them
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Step 1. Power outage
Before starting work, be sure to remove the battery (or disconnect the robot from the charging station and hold the power button for 10 seconds to completely shut down).
Step 2. Remove the bumper
Carefully place the bumper with a plastic blade on the side (on the side of the power button) and it is mounted on the latches — don't put too much effort into breaking the locks. In some models (Viomi). V3) The bumper is further screwed.
Step 3: Sensor cleanup
Wet the cotton swab in alcohol and gently wipe the transparent surface of the sensors (don't press hard!). Remove dust and greasy marks. For hard-to-reach places, use compressed air (canister).
Step 4: Contact check
If the problem persists after cleaning, check if the sensor contacts have moved away from the board. Carefully press the connectors (if they stagger) or reconnect them.
⚠️ Warning: Do not use abrasive materials ( sandpaper, hard brushes) to clean the lens, and avoid liquid on the board!
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If after cleaning the robot still does not see obstacles, try to reset the settings to the factory through the application Mi Home (Settings section). → Sometimes this helps with sensor software failures.
How to check the performance of the obstacle sensor
If you are not sure that the problem is in the sensor, you can make a simple diagnosis:
- Reaction test: Hold your hand to the robot at a distance of 10-15 cm. A correct sensor should cause the device to stop or change its trajectory.
- In-app check: In Mi Home, open the Device Status section – if the sensor is faulty, there will be a code error (e.g., 05 or 12).
- Visual inspection: Turn on the robot in a dark room – working IR sensors should light up slightly red.
For deep diagnostics, you can use debugging mode (not available on all models). For example, in DreameBot, press the Spot Cleaning button for 5 seconds, the robot will give a voice message about the status of the sensors.
If the sensor does not respond to any of the tests, it is likely that it has failed and needs to be replaced, in which case contact the service center or order a spare part (for example, on AliExpress by the sensor article, which is indicated on its body).
Frequent errors when working with obstacle sensors
Many users make mistakes that cause sensors to break down.
- 🔨 Power removal of the bumper - this leads to cracks in the latches.
- 💦 Using water for cleaning – moisture can close contacts.
- 🔥 Warming up sensors with a hair dryer at high temperature - this spoils plastic lenses.
- 🔧 Replacing the sensor without power outage - the risk of short circuit.
It's also a common mistake to confuse the obstacle sensor with the drop sensor, so if the robot falls down the stairs, it's not the IR sensors that are the problem, so check the bottom sensors (they're usually black and pointing to the floor).
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If the robot stopped seeing obstacles after updating the firmware, try rolling it back to the previous version, and sometimes new navigation algorithms conflict with old sensors.
Where to buy and how to replace the obstacle sensor
If the sensor is damaged, you can replace it yourself, and the cost of a spare part varies from 300 to 1500 rubles depending on the model.
- 🛒 AliExpress is the largest choice, but a long wait (search for "Xiaomi vacuum obstacle sensor") + robot").
- 🏬 Local service centers – often sell original parts.
- 🌍 eBay/Amazon – fast shipping, but high price.
How to replace the sensor:
- Shut the robot off the power.
- Remove the bumper (as described above).
- Unplug or disconnect the old sensor connector.
- Install a new sensor, connect contacts.
- Check the performance in test mode.
⚠️ Note: When replacing the sensor in models with a laser rangefinder (for example, Mi Robot Vacuum-Mop 2 Pro), you may need to calibrate through the service menu.
If you are not sure about your soldering skills, you should contact the service. The average cost of replacing a sensor in a workshop is 1000-2500 rubles.