Actuators in IoT are frequently lumped into the same category as IoT sensors, but while they interact closely with each other, they are separate components.
So, with this guide, we’re going to take a deep dive into the sometimes-overlooked actuator. We’re going to cover how they’re used in IoT, clear up the difference between them and sensors, and list the most common actuators you’ll come across in 2021. Let’s get into it.
What are actuators in IoT?
An actuator is a device that converts energy into motion. It does this by taking an electrical signal and combining it with an energy source. An actuator comes in a few different guises, including:
We’ll dive deeper into these below. However, now we’ve defined what an actuator is, let’s look at the difference between this and an IoT sensor.
What’s the difference between sensors and actuators in IoT?
Essentially, an actuator creates movement, whereas a sensor monitors environmental conditions. These conditions may include fluid levels, temperatures, vibrations, or voltage.
The main characteristics between sensors and actuators can be broken down further into the following:
- Electrical signaling – Actuators measure heat or motion energy in order to determine the resulting action. On the flipside, sensors work through electrical signaling to read the environmental conditions and perform their assigned task.
- Conversion direction – An actuator converts an electrical signal to a physical action. A sensor does the opposite, converting a physical attribute to an electrical signal.
- Inputs and outputs – Actuators track the outputs of machines and systems, whereas sensors look at the inputs from the environment.
If you want to learn more about the different types of sensors used in IoT, take a look at The Top 10 Sensor Types in IoT and their Applications
Different Actuator Types in IoT
Now we’ve looked at what separates actuators from sensors, we’re going to go deeper into the different actuators on the market and the function they serve.
The sole function of an actuator that’s used in a hydraulic control system is to convert the hydraulic energy supplied by the pump and processed by the control elements into useful work.
Actuators have either a linear or rotary output.
A pneumatic actuator is a device that converts energy – typically in the form of compressed air – into mechanical motion.
Pneumatic actuators are notable in their use for applications where the opening and closing of valves takes place. For this reason, they hold value within applications where there’s a fire or ignition risk.
Pneumatic actuators are also known in the industry by several different monikers, including:
- Pneumatic cylinders
- Air cylinders
- Air actuators
An electric actuator converts electricity into kinetic energy in either a single, linear, or rotary motion.
The motor of an electric actuator can operate at any voltage, however, the most common voltages used are:
- 230 VDC
- 208 VDC
- 115 VAC
- 24 VAC
- 24 VDC
- 12 VDC
They’re typically used in industrial applications associated with manufacturing valves, pumps, and motors.
A thermal actuator is a type of non-electric motor. It’s equipped with thermal sensitive material that’s capable of producing linear motion in response to temperature changes.
When used alongside other devices, a thermal actuator doesn’t require an outside power source to produce motion. Temperature changes can be used to perform tasks such as release latches, operate switches, and open or close valves.
They can be used for many applications and in many industries, including aerospace, automotive, agriculture, solar, and building services.
A magnetic actuator is a device that uses microelectromechanical systems (MEMS) to convert an electric current into a 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.
A relay is an electrically operated switch. The majority of relays use electromagnets to mechanically operate a switch. However, other operating principles can also be used, for example, solid-state relays.
It takes a relatively small amount of power to operate a relay coil. That being so, it can still be used to control motors, heaters, lamps, or AC circuits.
Read Our Other Resources
We’ve published a range of IoT resources for our community, including:
- A Guide to IoT Protocols & Standards, which provides a complete overview of all the major protocols and standards available.
- Buying versus building an IoT platform, which discusses how to choose the best option for you.
- Our guide on how to Develop IoT Apps and what platforms you can use.
- How to Choose the Best IoT WiFi Module and what to consider when making your choice.
- A complete Guide to Microcontrollers for IoT, which explains all your options when it comes to choosing an MCU for your project.