Explore an IoT Actuator Through an Example

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Updated October 29, 2026

An IoT actuator is a device in a connected system that can change something in the physical world. To understand an example, ask: what system controls it, what source of energy does it use, and what part creates motion? This is a way to study an example, not a universal list of actuator components.

Contents

In a controlled system, an actuator can receive a signal, use energy and produce motion; some types respond directly to heat or stored energy.

Control signal in a controlled system
Source of energy
Mechanism that makes motion

What you will learn

Use an example to explore an actuator's control system, energy source and motion.
Describe where an actuator gets its energy.
Explain where an actuator sits next to a sensor in an IoT system.

Before you start

Read "What Is the Internet of Things?" first. Knowing that connected objects can send and receive information is enough.

What does the control signal do?

In a controlled system, a control signal tells an actuator when and how to act. NIST describes an actuator as the mechanism by which a control system acts upon an environment. Some passive actuators can respond directly to heat or stored spring energy without a separate command.

The control system can take different forms. It can be software, for example a printer driver or a robot control system. It can also be a human or another agent.

The command to an actuator can come from software, from a fixed system or from a person.

Software
A fixed mechanical or electronic system
A person
The actuator

Where does the energy come from?

An actuator is operated by a source of energy. NIST lists electric current, hydraulic fluid pressure and pneumatic pressure as typical examples. Pneumatic pressure means pressure from compressed air.

A review on PubMed Central uses an active/passive classification: in that review’s terminology, active actuators need an electric source, while passive ones use natural or stored energy such as thermal expansion or a spring. NIST also lists hydraulic fluid pressure and pneumatic pressure alongside electric current as typical energy sources.

Energy for an actuator can be electric, pressurised fluid or compressed air; a spring is an example of stored energy.

Electric current
Hydraulic fluid under pressure
Compressed air
The actuator
A spring storing energy

How does energy become motion?

An actuator converts energy into motion. In some electric actuators, a motor creates rotation while transmission elements pass on or change that motion.

The same review says an electric rotary-to-linear actuator comprises electric motors and mechanical transmission elements. Examples of these elements are the ball and screw mechanism, the lead screw mechanism, the rack and pinion mechanism and the belt and pulley mechanism.

In its rotary-to-linear actuator example, the review says transmission elements slow the motor’s rotation and increase torque. The actuator then converts rotary motion into linear motion; torque in the transmission stage is not the output motion of the whole actuator.

The motor turns, and transmission elements change that turning into straight-line motion.

Electric motor
Transmission elements
Straight-line motion

The motor turns a lead screw and the block on it slides straight: rotation becomes straight-line motion.

Where does an actuator fit in IoT?

An actuator can cause a physical change in the environment, such as opening or closing a valve or turning on a motor. In a common example, a sensor detects, a control system decides and an actuator acts; not every system follows one fixed chain.

In a common automated setup, a sensor detects, a control system decides and an actuator acts. IBM says automation is possible when sensors and actuators work to resolve issues without human intervention.

A control flow: a sensor reports, a control system decides and a valve actuator makes a physical change.

Sensor
Control system
Valve-style actuator

Real-world example

Think of a gadget that moves by itself, for example a toy car or a fan, with an adult beside you. Ask what tells it to move, where its energy comes from and what part actually moves. These questions help you explore the example; they do not describe required parts of every actuator.

Common misunderstandings

An actuator is a kind of sensor. A sensor detects changes in the environment. An actuator causes physical changes in it.

Every actuator follows the same energy classification. One review groups active actuators that need electricity and passive ones that use natural or stored energy; NIST also lists hydraulic and pneumatic power.

Only computers can give commands to an actuator. The control system can also be a human or another agent.

When a control system is used, its signal can direct an actuator; NIST describes an actuator as the mechanism by which the control system acts upon an environment.
An actuator is operated by a source of energy, such as electric current, hydraulic fluid pressure or pneumatic pressure.
An actuator converts energy into motion; some examples use a motor and transmission elements. In a common IoT flow, a sensor detects, a control system decides and an actuator acts.

Terms in this article

English and Vietnamese terms, with the meanings used here. Hover, tap or Tab to a term with a dotted underline for an explanation as you read.

ActuatorBộ chấp hành: A mechanism that can change its environment; in a controlled system, a control system can act through it.
Control systemHệ thống điều khiển: A system that directs an actuator in a controlled design.
Control signalTín hiệu điều khiển: Information used to direct an actuator in a design with control signals.
MechanismCơ cấu: An arrangement of parts that transmits or changes motion within an actuator.
Transmission elementPhần tử truyền động: A component transmitting movement or force from a motor to the working part.
MotorĐộng cơ: A component that converts supplied energy into motion.
TorqueMô-men xoắn: A measure of turning effect; in some rotary transmissions, reducing speed can increase output torque.
ValveVan: A component that opens, closes or adjusts a flow of liquid or gas.

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