UNIT 1: Introduction to IoT

Introduction to IoT (Internet of Things):

IoT is a vast network of physical devices embedded with sensors, software, and electronics,
connected through the internet to exchange and collect data. This technology extends internet
connectivity beyond traditional devices like computers and smartphones to include everyday
appliances, gadgets, and equipment.

Key Features:

1. Things: Physical devices like appliances and gadgets.

2. Internet: The medium that connects these devices.

Purpose and Benefits:

● Enables remote control of devices across network infrastructure.

● Reduces human effort with autonomous control.
● Uses AI algorithms, data collection, and networks to make devices smart.
● Enhances convenience and efficiency in daily life and business.

Examples:

● Pet trackers, diabetes monitors, smart ACs, and wearables.

Definition:

IoT is a dynamic global network infrastructure with self-configuring capabilities, where physical
and virtual "things" have unique identities, use intelligent interfaces, and are seamlessly
integrated to share data.

By 2020, over 50 billion devices were predicted to be connected to the internet, highlighting
IoT's rapid expansion and significance in enabling smart communication and automation.

Characteristics of IoT:

1. Dynamic & Self-Adapting: IoT systems can adjust to changing contexts, operating
conditions, or environments. Example: A surveillance system adapting to new conditions.
2. Self-Configuring: IoT devices collaborate to provide specific functionalities without
manual intervention.
3. Interoperable Communication Protocols: Support multiple protocols to enable
seamless communication among devices and infrastructure.
4. Unique Identity: Every IoT device has a distinct identifier, such as an IP address,
ensuring individuality.
 5. Integration into Information Networks: IoT devices exchange data and communicate
with systems and other devices.

IoT Categories:

1. Consumer IoT (CIoT):

● Focuses on personal and home applications, such as smartphones, wearables, smart

assistants, and home appliances.
● Technologies: Wi-Fi, Bluetooth, ZigBee (short-range communication).
● Use Cases: Enhancing personal and home environments.

2. Commercial IoT:

● Expands IoT benefits to venues like office buildings, supermarkets, hotels, and
healthcare facilities.
● Use Cases: Environmental monitoring, facility access management, utility optimization,
and enhancing customer experiences.

3. Industrial IoT (IIoT):

● Aims to increase efficiency and productivity in industrial systems.

● Common in sectors like manufacturing, healthcare, agriculture, automotive, and logistics.
● Example: The Industrial Internet for factory automation and logistics optimization.

4. Infrastructure IoT:

● Focuses on creating smart urban and rural infrastructures (e.g., bridges, railways, wind
farms).
● Enhances efficiency, cost savings, and maintenance of infrastructure systems.
● Often considered a subset of IIoT but significant enough to be treated separately.

5. Internet of Military Things (IoMT):

● Also known as Battlefield IoT, it is used in military and battlefield scenarios.

● Applications: Situational awareness, risk assessment, and response improvement.
● Examples: Interconnected ships, drones, soldiers, and bases for strategic and
operational benefits.

Sensors

Definition:
A sensor is a device that detects a physical parameter and converts it into a signal suitable for
processing. The output signal can be electrical, mechanical, or optical and is often converted
into a human-readable form, such as changes in resistance, capacitance, or impedance.

Static Characteristics of a Sensor:

Static characteristics are measured after the sensor output stabilizes.

1. Sensitivity:
○ Measures the change in output relative to a unit change in input.
○ Example: A speaker with 89 dB SPL per Watt per meter.
2. Resolution:
○ The smallest detectable change in the input.
○ Example: Resolution of a ruler vs. Vernier calipers.
3. Linearity:
○ Determined by how closely the calibration curve (output vs. input) resembles a
straight line.
4. Drift:
○ Deviation from a reading over time under steady input.
○ Types:
■ Zero Drift: Change at a zero reading input level.
■ Full-Scale Drift: Change at a full-scale deflection input level.
○ Causes: Ambient conditions (temperature, pressure, humidity) or sensor aging.
5. Range:
○ The allowable input or output limits.
○ Example: Physical limitations of a pocket ruler.
6. Repeatability:
○ Consistency of sensor measurements under the same conditions in a short time
frame.
7. Reproducibility:
○ Similar to repeatability but includes long time lapses and recalibration between
measurements.

Dynamic Characteristics of a Sensor:

Dynamic characteristics define how a sensor responds over time:

1. Rise Time: Time taken to reach a certain percentage of the final value.
2. Delay Time: Time before the sensor starts responding.
3. Peak Time: Time to reach the maximum value in response.
4. Settling Time: Time to stabilize within a certain error margin.
 5. Percentage Error and Steady-State Error: Difference between actual and expected
readings during or after the transient period.

Classification of Sensors in IoT

IoT systems use various types of sensors to collect data from their surroundings. Below is a
detailed classification and description of commonly used IoT sensors:

1. Temperature Sensors

● Purpose: Detect air or object temperature and convert it into an electrical signal.

● Applications:
○ Monitoring soil temperature for agriculture.
○ Detecting overheating in industrial equipment like bearings.

2. Pressure Sensors

● Purpose: Measure the pressure (force per unit area) applied to the sensor.

● Applications:
○ Measuring atmospheric pressure.
 ○ Monitoring gas or liquid pressure in tanks or vessels.
○ Weighing objects.

3. Motion Sensors

● Purpose: Detect the movement of physical objects using technologies like passive
infrared (PIR), microwave, or ultrasonic.

● Applications:
○ Security systems and intrusion detection.
○ Automating doors, sinks, air conditioning, and heating systems.

4. Level Sensors

● Purpose: Measure the liquid level relative to a benchmark.

 ● Types:
○ Continuous Level Sensors: Provide real-time level readings (e.g., fuel gauges).
○ Point Level Sensors: Indicate if a liquid is above or below a specific threshold
(e.g., low-fuel warning lights).

5. Image Sensors

● Purpose: Capture images for digital storage and processing.

● Applications:
○ License plate recognition.
○ Facial recognition systems.
○ Quality control in automated production lines.
6. Proximity Sensors

● Purpose: Detect the presence or absence of objects near the sensor using different
technologies.

● Applications:
○ Automating lighting systems.
○ Detecting objects in manufacturing processes.

7. Water Quality Sensors

● Purpose: Measure parameters related to water quality.

● Parameters Monitored:
○ Chemical levels (e.g., chlorine, fluoride).
 ○ Oxygen levels (for algae and bacteria growth).
○ Electrical conductivity (indicates ion levels).
○ pH (acidity or alkalinity).
○ Turbidity (suspended solids).

8. Chemical Sensors

● Purpose: Detect the presence of specific chemicals, often for safety and process
control.

● Applications:
○ Monitoring industrial environments for leaks or unsafe conditions.

9. Gas Sensors

● Purpose: Detect specific gases (combustible, toxic, or flammable).

 ● Examples of Detectable Gases:
○ Carbon Monoxide (CO).
○ Hydrogen Sulfide (H2S).
○ Nitric Oxide (NO).
○ Ozone (O3).
● Applications: Industrial safety and air quality monitoring.

10. Smoke Sensors

● Purpose: Detect the presence of smoke, typically using optical or ionization detection
methods.

● Applications: Fire detection systems in homes, offices, and industrial settings.

11. Infrared (IR) Sensors

● Purpose: Detect infrared radiation emitted by objects.

● Applications:
○ Non-contact thermometers.
○ Heat signature analysis in electronics.
○ Blood flow and blood pressure monitoring in healthcare.

12. Acceleration Sensors (Accelerometers)

● Purpose: Measure the rate of change of velocity (acceleration) of an object.

● Applications:
○ Detecting free-fall conditions.
 ○ Measuring vibrations or rotational motion.

Actuators

An actuator is a mechanical device or system that moves or controls components within a

machine or system. It works by converting electrical signals into physical actions like movement,
force, or sound. Actuators receive control signals generated in response to sensor input and
perform the necessary physical actions.

Types of Actuators

1. Servo Motors

● Structure: Consists of a DC motor, gear train, potentiometer, integrated circuit, and an

output shaft.

● Function: Provides precise control of angular or linear position, velocity, and

acceleration.
● Applications:
○ Robotics for joint movement.
○ Precision control in remote-controlled cars, planes, or boats.

2. Stepper Motors

● Structure: A DC motor with multiple coils organized in groups called "phases."

 ● Function: Moves in discrete steps, allowing precise positioning and speed control by
energizing coils sequentially.
● Applications:
○ 3D printers for controlled movement.
○ CNC machines for exact positioning.

3. DC Motors (Continuous Rotation Motors)

● Structure: Converts electrical energy into mechanical energy.

 ● Function: Rotates continuously for general motion needs.
● Applications:
○ Robotics for wheel movement.
○ Simple mechanical toys and gadgets.

4. Linear Actuators

● Function: Creates motion in a straight line, unlike the rotational movement of typical
motors.
 ● Applications:
○ Industrial machinery like valves and dampers.
○ Disk drives, printers, and other peripherals requiring linear motion.

5. Relays

● Structure: An electrically operated switch, typically using an electromagnet to operate.

● Function: Controls high-power devices (e.g., motors or heaters) with a low-power

signal.
● Applications:
○ Switching AC circuits.
○ Controlling electrical loads like lamps or industrial equipment.

6. Solenoids
● Structure: A specially designed electromagnet that creates linear motion.

● Function: Used primarily in on/off applications such as locking, triggering, or latching

mechanisms.
● Applications:
○ Home appliances like washing machines.
○ Automobiles for door latches or starter mechanisms.
○ Pinball machines for plungers and bumpers.