Actuators In IoT

M4-R5.1 · Chapter 3: Sensors, Actuators and Microcontrollers · 4 min read

ACTUATORS IN IoT (Detailed Notes)

1. Introduction to Actuators

  • An actuator is a device that converts energy or an input signal into mechanical motion.

                            OR 

  • a physical device that converts one form of energy into another.

  • It is a physical device used to perform actions in real-world systems.
  • In IoT systems:
    • Sensors → detect environment
    • Actuators → perform action
  • Working Flow:
  • Actuators are considered output devices in IoT.

2. Role of Actuators in IoT

  • Receive signals from:
    • Microcontrollers (Arduino, Raspberry Pi)
    • IoT platforms
  • Perform actions like:
    • Switching ON/OFF devices
    • Moving mechanical parts
    • Controlling systems
  • Examples in IoT:
    • Smart fan (motor control)
    • Smart lock (servo motor)
    • Automated irrigation (valve control)

3. Types of Actuators

(As shown on Page 1)

3.1 Electrical Actuators (Electromechanical)

  • Convert electrical energy → mechanical motion
  • Most commonly used in IoT systems

Key Points:

  • Powered by motors
  • Provide motion, force, or torque
  • Easy to control using circuits

Examples:

  • DC motor
  • AC motor
  • Stepper motor
  • Servo motor

Types of Electric Actuators (Motors)

4.1 DC Motor

Key Points:

  • Operates on DC supply
  • Speed control is easy (by changing voltage)
  • Direction control:
    • Clockwise
    • Anticlockwise

Applications:

  • Fans
  • Toys
  • Small machines

4.2 AC Motor

(Page 2)

Key Points:

  • Works on AC supply
  • Runs at constant speed
  • Widely used and economical

Types:

  • Induction motor
  • Synchronous motor
  • Universal motor

Applications:

  • Household appliances
  • Industrial machines

4.3 Stepper Motor

(Page 2)

Key Points:

  • Moves in discrete steps
  • One full rotation is divided into equal steps
  • Works without feedback (open-loop system)

Advantages:

  • High accuracy in positioning
  • Easy control

Applications:

  • 3D printers
  • CNC machines
  • Robotics

4.4 Servo Motor

(Page 2)

Key Points:

  • High precision motor
  • Uses feedback system
  • Can rotate to a specific angle

Working:

  • Control circuit gives feedback about position
  • Motor adjusts accordingly

Types:

  • AC servo motor
  • DC servo motor

Applications:

  • Robotics
  • Camera control
  • Automation systems

3.2 Hydraulic Actuators

(Page 3)

  • Use liquid pressure to create motion

Working:

  • Fluid is pushed into a cylinder
  • Creates linear or rotary motion

Key Features:

  • Liquids are incompressible
  • Can generate very high force
  • Suitable for heavy-duty applications

Advantages:

  • High power output
  • Smooth operation

Disadvantages:

  • Requires maintenance
  • Leakage issues

Examples:

  • Hydraulic brakes
  • JCB machines
  • Lifting systems

3.3 Pneumatic Actuators

(Page 3)

  • Use compressed air to generate motion

Working:

  • Air pressure pushes piston → produces motion

Key Features:

  • Fast response
  • Reliable and safe
  • Works with small pressure changes

Advantages:

  • Clean and simple
  • Low cost

Disadvantages:

  • Less force than hydraulic systems
  • Requires air compressor

Examples:

  • Bicycle pump
  • Pneumatic brakes

3.4 Mechanical Actuators

(Page 3)

  • Convert rotary motion → linear motion

Working:

  • Uses mechanical components to transfer motion

Components Used:

  • Gears
  • Chains
  • Pulleys
  • Rails

Applications:

  • Simple machines
  • Mechanical control systems

3.5 Thermal & Magnetic Actuators

(Page 3–4)

Thermal Actuators:

  • Operate using heat (temperature changes)
  • Materials expand or contract

Example:

  • Thermostat

Magnetic Actuators:

  • Use magnetic field or electromagnetism

Example:

  • Electromagnets

Special Material:

  • Shape Memory Alloy (SMA)
    • Changes shape when heated
    • Returns to original shape when cooled