The Ultimate Guide to Sensors and Actuators in IoT

sensors and actuators in IoT

From performing simple tasks in the 80s to going irrelevant to coming back stronger again to automate in supply chains of large-scale industries, IoT has covered a long distance. In today’s where attention is the new currency and data is the new asset, IoT is no longer a cold hard technology that can be used only by industries and production lines.

Today IoT has so many smart sensors that they can do so much more fun things than just painting a piece of metal in a conveyor belt now they are capable of working in a huge network of machines and doing things like checking their own condition, notifying if something is off-normal and even predict any future problems. The data is used by sensors and actuators in IoT then the data is processed and analyzed and over time the changing data type is used to improvise the functionality of the IoT device.

As the days passing the sensors and actuators in IoT are becoming more faster, smarter, and more accurate but there is a misconception that sensors and actuators in IoT are the same things while they can be put into the same category as they’re closely related but they are certainly not the same thing as they work differently from each other.

So, here we talk about what are the differences between these two and how they are used in IoT, By this article, you will clear out every confusion regarding the difference between sensors and actuators in IoT.

Sensor definition in IoT

In simpler terms, the sensors in an IoT device are actual small physical devices that convert one energy into other. For example, a light sensor in your ambient light system checks the brightness nearby by turning the light into an electrical signal, the signal is then used by an actuator to increase or decrease the brightness of your ambient light system.

What is actuator in IoT

If you have learned what is a sensor it won’t be too hard for you to understand the actuator it works opposite to the sensor. It takes the electrical signal and converts it into certain physical actions. If we go back to the previous example of ambient light here, The actuator is what physically changes the lights into some other brightness or another color. Other places where the actuator is used are car airbags and hydraulic systems.

difference between sensors and actuators in IoT

What Connects Sensors and Actuators in IoT Device

In a smart IoT system, The sensor collects data and sends it to the control center. The control center processes the data depending on what they are programmed to do and then it commands the actuators to perform certain tasks. Basically, if the sensor is the brain and the actuator is the limb that performs the tasks it’s the main difference between sensors and actuators in IoT. Now let’s dive deeper into that.

Another difference between Sensors and Actuators in IoT Device

  • Change In Energies– The first diffrence between sensor and actuators in the principle they follow. Actuators measure heat or motion energy and peforms the physical task. Sensor pass them the energy depending on the environmental conditions that they collect with the help of electrical signal.
  • Collection Place– The second diffrence between sensors and actuators in Iot is sensor track the output from the environment where as actuator track the output from the control center.

Examples of Sensors and Actuators in IoT

Types of Sensors in IoT

To clearly understand what is the difference between Sensors and actuators in IoT, you have to understand what sensors are, more clearly, examples of sensors and actuators in IoT devices will make it easier for you to understand that. Sensors are small devices that make machines smarter. Depending on what environmental data they will gather they can be divided into many categories and many sensors do similar tasks like

Temperature sensor

manufacturing plants, warehouses, weather reporting systems, and agriculture use temperature sensors it’s by far the most common sensor for checking the thermal condition of the environment.

  • Thermistor– Its a type of resistor, whose resistance varies depending on the temperature. Thermistors are widely used as sensors in electronics for preventing excessive current increase. They measure the temperature depending on the resistance.
  • Resistance temperature detectors– They depend also on the resistance for the reading but instead of the the resistance itself, it depends on the rate of the change in resistance.
  • Thermocouples– Eletric-Current travells from high voltage to low voltage. Simmilarly every eletric circuit consists 2 conductors. This sensor measures the temperature by measuring the voltage diffrence between those 2 conductors.

Moisture Sensor

Apparently, Moisture Sensors may look like they are only used in Weather stations but they are also used in agriculture, environment monitoring, food supply chain, HVAC, and health monitoring.

  • Hair tension moisture sensor– Is the simplest and one of the oldest kind of sensor it uses a hair or synthetic fiber ponting to a scale that changes its length depending on the humidity.
  • Psychrometer– It consist 2 thermometer one is attach to a wet bulb another one is dry. The more humid the environment the less temperature the wet thermometer will show.

Light Sensor

Smart T.V.s, smartphones, tablets use this sensor to modify its brightness depending on ambient light. Its also used in smart city street lights that change the brightness depending on the ambient light for the better economy from electricity.

  • Photoresistor It depends on a photo sensitive elements which have a variable resistance depending on the radiation. If the sensor understands the ambient it dark it sends information to the connected actuator to turn on or brightent the light.
  • Photodiode When photon touches this photodiode they absorbe from here the electrons gets transfered in the connection. its basically used in industrial automation.

Motion Sensor

Obviously, motion sensors are mostly used in security systems but they are also used in smart cameras and automation devices.

  • Active, ultrasonic motion sensor– It sends ultrasonic waves and recieves when it returnes like a bat uses ultrasonic sounds to see at night.
  • Active, radar sensor– Works similarly to the previous one but uses electromagnetic waves.
  • Passive, infrared motion sensor– It detects changes in infrared radiation.

Noise Sensor

This sensor is used to monitor sound levels in a given environment. It can be used in cities to gather data regarding noise pollution.

  • Hydrophone– They are used in locating fish in the stream. They work by captering sound in the water
  • Geophone– They capture ground vibrations and converts ito electrical voltage it is often called a kind of sismometer.

Gyroscope Sensor

This sensor is used in navigation, robotics, and in every machine relating to rotation, it detects rotation and measures angular velocity.

  • Accelerometer– This sensor does not maintain a constant direction, but indicates the angular velocity of the object on which it is located it uses a mechanical gyroscope with limited mobility.
  • Heading indicator– Its a directional gyroscope or heading indicator that allows to observe the rotation of the body to which it is attached. The gyroscope is most often made as a fast rotating rigid object.

Chemical Sensor

They are used to detect chemical compounds present in the air

  • Electrochemical breathalyzer– It can measure the alchohol presence in human body by breathing into it. It can diffrienciate between citric acid, cigrettee smoke and menthol.
  • E-Nose – A set of detectors, that reacts to different types of particles contained in the environment or their different characteristics

sensors and actuators in IoT

Different Actuator Types in IoT

You learned what is the difference between sensors and actuators in IoT and also about some examples of sensors now we will for the next part of the examples of sensors and actuators in IoT we will put focus on the actuators.

Hydraulic Actuators

This Actuator operates by converting hydraulic power to do the mechanical tasks. Here the mechanical power is converted into rotary, leaner, and oscillatory motion. The actuator here captures output from motors and uses liquid as the pressure generator.

Pneumatic Actuators

This actuator works similar to the hydraulic actuator but it uses vacuum or compressed air to convert it into mechanical power they are weaker compared to hydraulic actuators.

Electrical Actuators

Similarly, electrical actuators use electrical energy to turn it into mechanical torque. The mechanical actuators are used in industrial places I valves pumps and motors mostly work in the following voltages.

Thermal Actuators

This can be called an electric less motor.  It’s equipped with thermal-sensitive material that’s capable of producing linear motion in response to temperature changes. Opposite to another actuator, it does not need an external power source. It is used to release latches, operate switches, and open or close valves.

Magnetic Actuators

This kind of actuator changes electronic magnetic current to mechanical output They operate in either a rotary or linear direction and can have continuous or limited motion. Magnetic actuators are used within the aerospace, automotive industry, healthcare, computers, and many other industries

sensors and actuators in IoT


Sensors and actuators in IoT are a quite large topic to learn but thinking they are the same is not a good place to start with. If you were paying attention you must have understood the difference between sensors and actuators in IoT systems, now you have this to brag about thanks for reading our ultimate guide to sensors and actuators in IoT.

Have a great day.