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Sensors in Robot Vacuums That Help Them Navigate


Since robot vacuums were first invented, these smart cleaning devices have evolved greatly, especially when it comes to the technologies that help them with navigation. From the first robot vacuum cleaner model, the Electrolux Trilobite having problems avoiding objects, we now have advanced robot vacuums that can now even detect pet waste to avoid such.

The advanced and accurate way in which robot vacuums navigate is largely thanks to the sensors they use. Let’s take a look at the different sensors a robot vacuum cleaner makes use of to help with their navigation and cleaning.

What is the Need for Sensors in Robots?

Sensors in Robot Vacuums That Help Them Navigate

Simply put, a robot vacuum cleaner needs sensors so it can determine the kind of object that is right in front of it to prevent any collisions and for mapping out the room. Without sensors, a robot vacuum cleaner may be comparable to that of a regular vacuum cleaner due to the lack of artificial intelligence and mapping capabilities.

There are varying sensors a robot vacuum cleaner may have as each sensor will have its own function. High-end models will have multiple sensors and technologies, which is why they are priced higher compared to an entry-level robot vacuum cleaner.

How Many Sensors Does a Robot Vacuum Have?

Sensors in Robot Vacuums That Help Them Navigate

Generally, there are four types of sensors a typical robot vacuum cleaner may have. These are the ultrasonic time-of-light (ToF) sensors, short-range ultrasonic ToF sensors, vSLAM, and LiDAR. However, a high-end robot vacuum cleaner can have up to ten sensors.

Ultrasonic Time-of-Light (ToF) Sensors

These types of sensors allow a robot vacuum to determine what is in front of it. It can work in any lighting condition, which allows a robot vacuum cleaner to still detect items and clean in the dark. These sensors will allow a robot vacuum cleaner to gauge a millimeter-accurate range of measurements, which is important for a robot vacuum to avoid coming into accidents or scratching furniture.

Short-Range Ultrasonic ToF Sensors

These sensors help a robotic vacuum cleaner distinguish different floor types. The sensors make use of reflected ultrasonic signals that will be processed by a robotic vacuum in determining if the floor is hard or soft. This allows it to switch up the suction power exerted or mode it in if it moves from hardwood floors to carpets.

These sensors are also connected with the cliff detection feature of a robot vacuum. Without them, a robotic vacuum may end up falling down the stairs and getting damaged.


Most of the time, a high-end robot vacuum will make use of both these sensors for their mapping technology. These sensors allow a robot vacuum to build a virtual map of the room so it can easily memorize the layout. Essentially, a robot vacuum will “trace” the walls and create a path so it knows the zones it can or can’t enter.

Inertial Measurement Units (IMU)

To let a robot vacuum know that it’s not moving or staying in the same place as it cleans, the IMU sensors will activate. These sensors help a robot vacuum’s wheel rotations and even be aware of where and when to pick up its last cleaning session should the batteries have died before.

Smart Speaker Microphones

A high-end robot vacuum will have voice technology embedded in it. Hence, a robot vacuum may have sensors for its smart speaker microphones for voice assistance functions. These sensors will also help assist a robot vacuum in managing the noise signal and its noise motors so it will be able to hear the user’s voice for any commands while in the middle of a vacuum session.

Embedded Motor Controllers

The accuracy in where the wheels of a robot vacuum will turn is thanks to the embedded motor controllers sensors. It allows a robot vacuum to be flexible, scalable, and move to a certain level of high accuracy. The use of light sensors will also help a robotic vacuum in measuring the wheels’ rotation. Said sensors will also help a robot vacuum find out how far it has already traveled from the docking station to the zone currently in.

Pressure Sensors

A robot vacuum will be able to measure and monitor the level of dust and debris it has collected thanks to pressure sensors. If the robot vacuum is a model that has a self-emptying feature, then the pressure sensors will trigger the robotic vacuum to empty out the dustbin once it’s full due to estimated monitoring of the flow of air done by the pressure sensors.


Depending on the robot vacuum, the model can self-dock to recharge its batteries. A robotic vacuum that is able to do this has an auto-recharging sensor that will instruct itself to charge because it is about to run out of batteries.


These temperature sensors will allow a robotic vacuum to monitor the running temperature of its MCU or MPU. This is important since it can trigger a robotic vacuum to stop if it’s too hot. The robotic vacuum can also run a system diagnostics test to check if there’s anything wrong with it.

The same sensors can also monitor the temperatures of a robotic vacuum’s motors and brush gears. Again, when a robotic vacuum is too hot, you can also check if any items or debris are caught in the wheels or brushes as these can be the cause of the spike in heat.

Where are the Sensors of a Robot Vacuum?

Sensors in Robot Vacuums That Help Them Navigate

Generally, the sensors of a robot vacuum can be found on its bottom or bumper. However, a robot vacuum with a camera or laser can place its sensors on top. With that said, the location will vary depending on what these sensors are.

It’s important for the user to know what kind of sensors are embedded in the robot vacuum as one will have to clean these every now and then. Failure to clean the sensors can lead to damage in the long run and eventually make one’s robot vacuum not perform at its best.

What is a LiDAR Sensor in a Robot Vacuum?

LiDAR stands for Light Detection and Ranging. From the name alone, LiDAR technology is a type of laser that will bounce off light waves on the surrounding wall coming from the robot vacuum. This will help the robot vacuum measure and calculate the distance of an object from where it’s standing so it can locate and move around the house accurately.

This type of technology will help a robot vacuum prevent any collisions, bumping into furniture, and even falling off the stairs. The LiDAR is usually placed under a cap and will be located at the top of a robot vacuum.

Final Note

With all these varying sensors, it’s no wonder why a robot vacuum is truly an advanced smart device. However, since having multiple sensors in one device can shoot up the price, we have created a guide on the best robot vacuums you can own ranging from high-end to budget models.

Sota Takahashi

Sota Takahashi is a Japanese-born electrical engineer. At the age of 18, he moved to Seattle and completed his Electrical Engineering degree at the University of Washington, Seattle. Being a fan of all things tech, he channels his geeky side through this website, and with his wife Linda, shares knowledge about robot pets and how they can be lifelong and advantageous companions for both children and the elderly.

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