The Ultimate Guide to Sensors and Actuators in IoT

sensors and actuators in IoT

From performing simple tasks in the 80s to going irrelevant and coming back stronger to automate supply chains in large-scale industries, the IoT has covered a long distance. In today’s world, 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 processed and analyzed. Over time, the changing types of data are used to improve the functionality of the IoT device.

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

So, here we talk about the differences between these two and how they are used in the IoT. By this article, you will clear up 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 type of energy into another. For example, a light sensor in your atmosphere lighting 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 atmosphere lighting system.

What is an actuator in IoT?

If you have learned what a sensor is, it won’t be too hard for you to understand the actuator, which works in the opposite direction. 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.

IoT Actuators are in charge of an object’s actual movement. It could be a machine that has the ability to move objects and is powered by a variety of sources, including a battery, electricity, or human-created energy.

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. According to its programming, the control center uses the data before instructing the actuators to carry out certain actions. Basically, if the sensor is the brain and the actuator is the limb that performs the tasks, that’s the main difference between sensors and actuators in IoT. Now let’s dive deeper into that.

Difference between Sensors and Actuators in IoT

  • Change In Energies– The first difference between sensors and actuators is the principle they follow. Actuators measure heat or motion energy and perform a physical task. Sensors pass them the energy depending on the environmental conditions that they collect with the help of an electrical signal.
  • Collection Place– The second difference between sensors and actuators in IoT is sensor tracks the output from the environment whereas the actuator tracks the output from the control center.

Examples of Sensors and Actuators in IoT

Different Types of Sensors in IoT

To clearly understand the difference between sensors and actuators in the 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 resistance itself, it depends on the rate of the change in resistance.
  • Thermocouples– Electric-Current travels from high voltage to low voltage. Similarly, every electric circuit consists of 2 conductors. This sensor measures the temperature by measuring the voltage difference 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– This is the simplest and one of the oldest kinds of sensor it uses a hair or synthetic fiber pointing to a scale that changes its length depending on the humidity.
  • Psychrometer– It consists of 2 thermometers one is attached to a wet bulb another one is dry. The more humid the environment the less temperature the wet thermometer will show.

Light Sensor

Smart TVs, smartphones, and tablets use this sensor to modify their brightness depending on ambient light. It’s also used in smart city streetlights that change brightness depending on the ambient light for better energy efficiency.

  • Photoresistor It depends on photo-sensitive elements which have a variable resistance depending on the radiation. If the sensor understands the ambient is dark it sends information to the connected actuator to turn on or brighten the light.
  • Photodiode When a photon touches this photodiode and absorbs from here the electrons get transferred in the connection. it’s 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 receives them when it returns like a bat using 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 capturing sound in the water
  • Geophone– They capture ground vibrations and convert them into electrical voltage it is often called a kind of seismometer.

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– It’s a directional gyroscope or heading indicator that allows observing 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 alcohol present in the human body by breathing into it. It can differentiate between citric acid, cigarette 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 the difference is between sensors and actuators in the IoT and also about some examples of sensors. For the next part of the examples of sensors and actuators in IoT, we will put the focus on the actuators.

Hydraulic Actuators

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

Advantages :

  • Hydraulic actuators have a big force capacity and high speed.
  • Used to lower or raise the vehicles in automotive transport carriers as well as to clamp and solder.

Disadvantages :

  • Leaks in hydraulic fluid can reduce performance and complicate cleaning.
  • Heat exchangers, noise-canceling equipment, and high-maintenance systems are needed.

Pneumatic Actuators

This actuator works similarly to the hydraulic actuator, but it uses vacuum or compressed air to convert it into mechanical power. It is weaker compared to hydraulic actuators.

Advantages :

  • They are a cheap alternative and are useful in situations where using air instead of chemicals is better, as when temperatures are very high.
  • They are strong, need a little repair, and have a longer useful life.
  • Starting and stopping the motion both happen very quickly.

Disadvantages :

  • Pressure loss could reduce its performance.
  • The compressed air must be operating constantly.
  • Air requires repair and is subject to pollution.

Electrical Actuators

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

Advantages :

  • Due to its ability to automate industrial devices, it has many uses across numerous sectors.
  • Due to the lack of fluid leaks, it is easier to operate and makes less noise.
  • It offers the highest control accuracy positioning and may be modified.

Disadvantages :

  • It is expensive. It depends a lot on environmental conditions.

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.


  • A thermostatic or thermal valve’s internal thermal actuator allows it to function as a single unit that includes temperature sensing, actuating, and fluid control operations.
  • The thermal valve is resistant to power failures and dangerous situations like short circuits because it does not require an electricity supply. As a result, reliability and safety are improved over a conventional system.


  • A thermostatic or thermal valve’s internal thermal actuator enables it to function as a single unit that combines temperature sensing and fluid control features.
  • Since the thermal valve doesn’t require an electricity source, it is exposed to power failures and possibly dangerous situations like short circuits.

Magnetic Actuators

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


  • High press and actuation force 
  • Full-linear, direct transduction 
  • Actuation in both directions
  • Remote actuation that is capacitive
  • Least-powerful actuation


  • Extreme discharge
  • Manufacturing of the coil
  • Micromagnet incorporation into the MEMS device
  • Compatibility of processes and materials

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.