An actuator is a system or device that moves or controls a mechanism in response to a control signal. In IoT devices, sensors gather environmental data, and based on this data, actuators perform actions like moving, controlling, or adjusting the system’s operation.

Example: Servo Motor

A servo motor is a type of actuator used in IoT, which can rotate to a specified angular position (e.g., 90°, 180°).

How Actuators Work in IoT Devices:

• Controller: Processes the sensor data.
• Actuator: Executes the necessary action based on the control signal from the controller (e.g., rotating a motor or adjusting a valve).

Types of Actuators:

1. Hydraulic Actuators:

   • How it works: Uses hydraulic power (fluid pressure) to produce movement.
   • Example: Construction equipment (e.g., excavators).
   • Advantages: High force and speed.
   • Disadvantages: Expensive, leaks can cause issues, requires maintenance.

2. Pneumatic Actuators:

   • How it works: Uses compressed air to generate motion (linear or rotary).
   • Example: Robotics, pneumatic fingers.
   • Advantages: Low cost, durable, fast operation.
   • Disadvantages: Loss of pressure affects efficiency, requires continuous air supply.

3. Electrical Actuators:

   • How it works: Uses electrical energy (via motors) to produce mechanical movement.
   • Example: Solenoid-based electric bell.
   • Advantages: High control precision, low noise, safe (no fluid leaks).
   • Disadvantages: Expensive, sensitive to environmental conditions.

4. Other Actuators:

   • Thermal/Magnetic Actuators: Actuated by thermal or magnetic energy (e.g., Shape Memory Alloys, Piezo motors).
   • Mechanical Actuators: Convert rotary to linear motion using gears, pulleys, etc. (e.g., crankshaft).
   • Soft Actuators: Use soft materials to generate movement.
   • Shape Memory Polymers: Materials that change shape when heated or cooled.
   • Light Activated Polymers: Materials that change shape or properties when exposed to light.