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Differences Between IoT Sensor And IoT Actuators

Differences Between IoT Sensor And IoT Actuators

Guest Writer
Guest Writer
PA Engineer

Automation in the modern world reigns supreme. Initially employed at plants and factories to spare humans physically laborious and repetitive operations automated devices and cobots have left shop floors and spread across a huge range of activities – from medicine and aerospace to defense and agriculture.

Appreciating the convenience and comfort that these tireless silent assistants bring, we invited them into our homes where they set about streamlining our mundane chores and leisure time pursuits. Automated gimmicks inundated our kitchens and bedrooms, dens and garages turning them into high-tech havens where humans can lay back and let technologies pander to all their whims.

The next logical step down the road to total automation of our environment is marrying all the devices to enable their cooperation instead of dealing with a lot of them piecemeal. And this step was made with the inauguration of IoT – the Internet of Things.

Photo of industrial engineer using the software on a tablet to monitoring robot arm in automotive manufacturing


IoT Explained

To put it simply, the IoT system comprises objects connected to the Internet. Not just smartphones or computers but a whole gamut of electronic gadgets and mechanical appliances. Being thus linked together smart IoT devices can exchange data over the network and act in the way they were programmed to requiring no human participation that is neither interaction of people among themselves nor with computers. In fact, the IoT concept serves to bridge the gap between the physical and digital worlds. As a result, people attain and exercise control over a plethora of processes and environments that once we’re out of their reach.

How Do IoT Devices Work?

The functioning of IoT systems involves three-layer architecture.

Layer 1 is physical. It includes connected sensors that collect data with a further transfer of it. Since potentially these sensors can produce any kind of data, for the industrial IoT application it is important to filter the received information in order to sift out irrelevant messages and highlight urgent ones (for instance, threat detection, abrupt shutdowns, etc.). If the IoT data collection necessitates subsequent deep analysis it shouldn’t be stored on the company’s computers but relegated to the cloud.

Layer 2 is essentially an IoT sensor network supplied with DAS (data acquisition system). The latter is used to convert signals obtained from data sensors (usually analog waveforms) into digital values that are processed by a computer. Then the internet gateway directs the digitalized data to Layer 3 over Wi-Fi or wired local area network. Another compulsory prerequisite of data transmission is middleware. It is software that connects the database and applications and ensures the cohesion and management of all IoT components.

Layer 3 is where the reaction to the data takes place. The devices responsible for it receive an order to start functioning in accordance with the preset algorithms.

Industrial Internet of Things: A Sample of Operation

Let’s look at how all these functions in agriculture.

Smart robotic in agriculture spraying fertilizer


Internet of things sensors gathers information on the amount of moisture in the soil to determine how intensive the watering of crops should be. This data is supplemented by the weather forecast obtained from the internet that informs whether any rain is expected in a given location any time soon. Responding to this input data the irrigation system turns on automatically (if a dry spell is anticipated) discharging the exact measure of water that the crops require.

As you can see the adequate operation of the entire system largely depends on sensors for the Internet of Things.

IoT Sensors

What are the sensors? They are modules that detect environmental changes to information about them other elements of the system they are linked to. To make it possible the signals about the condition of the surrounding world are converted into digital code. So, in fact, an IoT sensor is a subtype of a transducer – a device that transforms one energy kind into another. The difference between sensor and transducer is that the latter is a more general term subsuming all appliances enabling energy conversion while the former converts only physical phenomena into electric signals.

Today, the variety of sensors is astounding. Some of them (called passive) doesn’t require any external power source to function, others (aka active) do. According to the method of detection implemented in them, sensors are divided into mechanical, thermal, electric, chemical, etc. All of these are based sensors, which means that they can only measure some value but not analyze the received input since they aren’t equipped with processors. IoT sensor technology makes use of two completely different kinds of devices.

Smart sensors are equipped with digital motion processors (DMPs) that can analyze the obtained data before transmitting it via the communication module to the network layer. Such sensors may also contain compensation filters, amplifiers, and other components facilitating their operation.

Drone quadcopter DJI Phantom 4 with high-resolution digital camera and front obstacle sensors


Intelligent sensors are upgraded smart sensors that on top of what the latter can do are capable of self-validation and identification as well as adaptation and testing. Moreover, they may even function as an IoT controller handling responses which makes them effectively specialized hardware.

However important sensors for IoT might be it is Layer 3 devices that ultimately determine task implementation.

IoT Actuators

What is an actuator used for? Placed at Layer 3 of the IoT system it starts the appliance it is attached to into action. So, in fact, the sensor and actuators are two kinds of transducers with the opposite direction of operation. The difference between sensor and actuator is that the former accepts physical input and turns it into electrical impulses while the latter performs a physical action on receiving an electrical input generated by the data that is obtained from the sensor. In the case of an actuator, data triggers an event and not vice versa.

Examples of Actuators

The basic purpose of actuators is to provide motion. It is effected by leveraging various energy sources that enable the categorization of actuators into four distinct types.

Thermal actuators use heat to generate motion while hydraulic and pneumatic actuators utilize compressed liquid or air respectively to the same end. Being quite powerful these actuators, however, incur cleanliness issues and can hardly provide the precision of movement. So it is no wonder that the most widespread type is the electric actuator conventionally powered by a 12V battery. It can guarantee smooth motion as well as accurate positioning.

The type of movement actuators yield allows their classification into rotary, oscillatory, and linear among which the latter is the most popular. Being compact, clean, reliable, and sturdy linear actuators are utilized in a wide range of industries including robotics, agriculture, solar energy, surgery, pharmaceutics, etc. These devices also find extensive application in domestic automation. Hidden TV sets and monitors, adjusting height desks, pop-up kitchen racks and automatic window openers are but a few actuator examples that bring tons of comfort and a tinge of futuristic swank into our homes.

In the automated world of today, previously stand-alone appliances and gadgets are increasingly integrated into one network. IoT sensors and actuators ensure accurate data assemblage and exact reaction stipulated by the prior programming thus paving the way to streamlining numerous aspects of our life.

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