Difference Between Actuator and Sensor

In this tutorial, we will learn the difference between a sensor and an actuator. The main difference between a sensor and an actuator is that an actuator is an output device and a sensor is an input device. First, we will introduce the actuator, and then we will explain the sensors and their types. Actuators and sensors are different parts of machinery upon which the working of machinery depends. Here we have a brief introduction and the technical differences between them.

Introduction to Actuators

The part of machinery upon which the movement and guidance of an apparatus are dependent is actually an actuator. Most of the actuators are guided by software because they turn the control signal into spontaneous action, but in the past, the actuators were based upon hydraulic, pneumatic, electric, thermal, or mechanical means.

Types of Actuators

Some types of actuators include:

• Electric motors
• Comb drive
• Hydraulic cylinder
• Pneumatic cylinder

Introduction to Sensors

For the detection of different actions and gestures in the surrounding environment, we call this device or element a sensor. After detection of any gesture, it provides the information to the electronic device. Sensors can only work with other electronic components.

Types of Sensors

There are a large variety of different types of sensors. Some of them are listed below:

• Temperature sensor
• Tilt sensor
• Ultrasonic sensor
• Accelerometer

Difference Between Actuator and Sensor

Sensors and actuators are the most important parts of any machinery, as they provide the information to do the work. We use sensors and actuators widely in our daily routine in different mechanical, electrical, or other equipment or devices.

Sensors and actuators have a number of similarities and dissimilarities in their functioning or processing. Here we have listed the differences between an actuator and a sensor.

Differences

• The main difference between an actuator and a sensor is that the sensor converts the physical gesture into electrical signals and does different things. Whereas the actuator is responsible for the conversion of an electrical signal into mechanical work.
• Sensors measure discrete as well as continuous process variables. On the other hand, the use of actuators is to impel the parameters of both discrete and continuous processes.
• The use of sensors helps detect electrical signals in different electrical applications. On the other hand, actuators are very useful in the production of energy in the form of heat and motion.
• The sensors are an input device because we place them at the input port of the machine. However, actuators are an output device, as we mostly place them at the output port of the machinery.
• Sensors are the ones that act as brains because they provide information to do work.
• Sensors provide us with electrical energy by direct conversion of thermal energy, hence the name thermocouple. Two metallic wires that connect to the single terminal form a joint. That joint heats up when the voltage passes through it. The name of this effect is after the scientist’s name: Seedbeck coefficient or effect. In this way, the voltages are directly proportional to the temperature of the joints. There’s a type of actuator called a bimetallic strip that converts the thermal energy into mechanical output. When the material heats up, the distance between different atoms or molecules increases. Because of the large number of atoms in a material, it expands considerably. The opposite reaction occurs when the temperature decreases; most of the metals contract.

Applications of Sensors and Actuators

Mechanics

• The use of mechanical sensors is to measure atmospheric pressure; the name of one such sensor is a barometer. The barometer tube holds mercury, so when the atmospheric pressure increases, the level of mercury in the tube also increases.
• In mechanics, the actuator gives the result in linear motion from the physical rotatory input given to the actuators. A screw jack is the most common example of a mechanical actuator. So, when we tighten or rotate the screw of the screw jack, the legs of the jack move together. Thus, a mechanical actuator converts mechanical rotation into linear motion.

Electrical

• An electrical sensor is another type of sensor that we use to sense the quantity of electric current that passes through the conductor. This process involves different energy conversions, i.e., electrical to magnetic and magnetic to mechanical rotation.
• While an electric motor is a type of electric actuator, the most common type of electric actuator is a DC motor. DC motors operate on the current flowing through the coil. Which creates a magnetic field around the coil. Electrical actuators convert electrical energy into magnetic energy for mechanical output in the form of motion.

Automotive

• A sensor in the automotive industry determines whether the consumption of fuel is smooth or is igniting. Ignition of the fuel causes major damage to the car, like broken engine rings, bearing effects, and many more. With the help of sensors, we are able to know if the fuel is burning adequately or not. Because the cold fuel is denser and restricts the car’s ability to move smoothly.
• However, in automotive engines, an actuator controls the futile speed of the car. Actuators also do air flutter adjustment and are responsible for the enhancement of force. The actuators with this technique help by providing the driver or passengers with full safety. The use of actuators also includes controlling the redistribution of exhaust gas to increase performance.

Hydraulic

• Hydraulic sensors are very popular in the field of water distribution. So we basically use a hydraulic sensor to measure the pressure and flow of water. These sensors can act as gauges. In a water distribution system, we use hydraulic sensors to measure momentary pressures and pipe bursts. A hydraulic sensor is also used to measure the velocity of water. Electromagnetic and vortex swirl measurements are the modern methods of flow metering.
• On the other side, hydraulic actuators for the easy sliding of a piston contain a cylindrical hollow tube. The movement of a piston in a single direction means that pressure is applied only to one side of the piston. This is known as single acting. During the movement of the piston in a single direction, a spring is used for the return blow. There’s another type of pressure acting known as double acting. In this case, pressure is applied across both sides of the piston. Pressure contradiction among the different sides of the piston is the process that causes the piston to move.

Robotics

• Sensors play vital roles in robotics. Sensors are the ones that allow the robot to move, hear, see, and touch. The use of sensors in robotics also increases the performance of robots to a large extent. With the use of sensors, robots are made in the same way to act like human beings.
• On the contrary, actuators are used to make mechanical movements. We could say actuators, or, in other words, the muscles of robots.

Sensors and actuators both play a very important role in a machine.

Conclusion

In conclusion, this tutorial provides an in-depth overview of the differences between the actuator and sensor. It covers the introduction, types, and differences of both the sensor and the actuator. This helps us better understand the workings and applications while also improving our concept. Hopefully, this was helpful in expanding your knowledge of this topic.

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This concludes today’s article. If you face any issues or difficulties, let us know in the comment section below.