Hardware for IoT
IoT (Internet of Things) means devices connect to the internet and share data.
Example:
A smart watch counts your steps.
Smart AC turns on from the mobile app.
A smart door lock opens using a phone.
To build IoT systems, we need hardware (physical devices).
Sensors
What is a Sensor?
A sensor detects something from the environment and sends data.
In simple words:
👉 Sensor = “Feeling organ” of a device.
Humans use their eyes and ears.
Devices use sensors.
Common Types of Sensors
Temperature sensor → measures heat
Light sensor → measures light
Motion sensor → detects movement
Gas sensor → detects gas
Humidity sensor → measures moisture in air
Real-Life Examples
Your phone auto-adjusts brightness → uses light sensor.
College lab thermometer → temperature sensor.
Mall automatic door → motion sensor.
Smart farming system → soil moisture sensor.
How Sensor Works (Simple Steps)
Sensor detects change.
It converts it into electrical signal.
Microcontroller reads that signal.
Device takes action.
Remember This (Exam Definition)
Sensor: A device that detects physical changes and converts them into signals.
Digital Sensors
What is a Digital Sensor?
A digital sensor gives output in 0 and 1 (ON or OFF).
Simple meaning:
👉 It gives clear YES or NO output.
Example
Motion detected = 1
No motion = 0
Like:
Switch ON or OFF.
Real-Life Example
College biometric machine.
Automatic lights in corridor.
Door open alarm system.
Difference: Analog vs Digital Sensor
| Feature | Analog Sensor | Digital Sensor |
|---|---|---|
| Output | Continuous value | 0 or 1 |
| Example | Temperature reading 28.5°C | Motion detected (Yes/No) |
| Use | Weather systems | Security systems |
Exam Tip
They often ask:
👉 Difference between analog and digital sensors (3–5
marks)
Actuators
What is an Actuator?
Actuator performs action.
If sensor is “eye”,
Actuator is “hand”.
What Actuator Does?
Moves motor
Turns light ON/OFF
Opens door
Sprays water
Real-Life Examples
Smart fan changes speed.
Smart irrigation system waters plants.
Automatic parking gate opens.
Simple Flow Diagram
Sensor → Controller → Actuator
Example:
Temperature high → Controller detects → Fan turns ON
Remember This
Sensor detects. Actuator acts.
RFID Technology
What is RFID?
RFID means Radio Frequency Identification.
It uses radio waves to identify objects.
Parts of RFID
RFID Tag → Attached to object
RFID Reader → Reads the tag
Database → Stores information
Real-Life Examples
College ID card scan
Metro card
Shopping mall security tags
Toll plaza FASTag
Why RFID Important in IoT?
Tracks objects
Improves security
Saves time
Exam Definition
RFID is a wireless system that uses radio waves to identify and track objects.
Wireless Sensor Networks (WSN)
What is Wireless Sensor Network?
Group of sensors connected wirelessly.
They collect and send data together.
Example
Weather monitoring system
Smart farming
Forest fire detection
College Example
Cameras + temperature sensors in campus connected wirelessly.
Why WSN Important?
No wires needed
Covers large area
Easy installation
Participatory Sensing Technology
What is Participatory Sensing?
People use their mobile phones to collect data.
Simple meaning:
👉 Humans become sensors.
Examples
Google Maps traffic updates
Pollution apps
Health tracking apps
When many users share data → system becomes smart.
Why Important?
Low cost
Real-time data
Useful for smart cities
Embedded Platforms for IoT
Embedded system means small computer inside a device.
Example:
Washing machine controller
Microwave timer
Smart TV board
Embedded Computing Basics
What is Embedded Computing?
Small computer system designed for specific task.
Not like normal PC.
Main Parts
Processor (brain)
Memory
Input devices
Output devices
Example
Smart AC:
Sensor → Detect temperature
Processor → Decide action
Actuator → Turn compressor ON
Remember This
Embedded system = Small computer + Specific job
IoT Supported Hardware Platforms
These boards help us build IoT projects.
Arduino
What is Arduino?
Small microcontroller board.
Easy for beginners.
Features
Low cost
Easy coding
Many sensors support
College Example
Students build:
Smart dustbin
Smart parking system
Fire alarm system
Exam Tip
Arduino is best for simple IoT projects.
NetArduino
What is NetArduino?
Similar to Arduino but supports .NET programming.
Used for advanced applications.
Example
Used in industrial automation systems.
Raspberry Pi
What is Raspberry Pi?
Small computer like mini PC.
More powerful than Arduino.
Features
Supports Linux OS
Connects keyboard and monitor
Internet ready
Real-Life Example
Home media center
Smart home server
CCTV system
Difference: Arduino vs Raspberry Pi
| Feature | Arduino | Raspberry Pi |
|---|---|---|
| Type | Microcontroller | Mini Computer |
| OS | No OS | Linux OS |
| Power | Low | High |
| Use | Simple control | Complex projects |
BeagleBone
What is BeagleBone?
Single board computer like Raspberry Pi.
Used in robotics and automation.
Example
Industrial machines
Robotics labs
Intel Galileo
What is Intel Galileo?
Board developed by Intel for IoT learning.
Supports Arduino shields.
Used In
Smart city projects
Advanced IoT systems
ARM Cortex
What is ARM Cortex?
Processor design used inside many IoT devices.
Used in:
Smartphones
Smart watches
IoT boards
Why Important?
Low power
High efficiency
Small size
Quick Comparison Table
| Platform | Best For | Level |
|---|---|---|
| Arduino | Beginner projects | Easy |
| Raspberry Pi | Complex IoT | Medium |
| BeagleBone | Robotics | Advanced |
| Intel Galileo | Industrial IoT | Advanced |
| ARM Cortex | Inside devices | Professional |
Important Exam Questions
Short Questions (2–3 Marks)
Define sensor.
What is actuator?
What is RFID?
Define embedded system.
Difference between Arduino and Raspberry Pi.
Long Questions (5–10 Marks)
Explain sensors and actuators with examples.
Explain RFID technology with diagram.
Compare IoT hardware platforms.
Explain Wireless Sensor Networks.
Key Points for Quick Revision
Sensor detects changes.
Digital sensor gives 0 or 1.
Actuator performs action.
RFID uses radio waves.
WSN connects sensors wirelessly.
Arduino is simple.
Raspberry Pi is powerful.
Embedded system does specific task.
Final Summary
IoT hardware includes sensors, actuators, RFID, and wireless networks.
Sensors collect data.
Actuators perform action.
RFID tracks
objects.
WSN connects many sensors.
Embedded platforms like Arduino and Raspberry Pi help build IoT systems.
Remember:
👉 Detect → Process → Act
That is the heart of IoT.
These notes help you understand clearly and revise quickly before exams.