Introduction to IoT

The Internet of Things (IoT) is a network of physical devices — sensors, actuators, appliances, vehicles, and more — that are embedded with computing hardware and connected to the internet so they can collect, exchange, and act on data with minimal human involvement.

What is IoT?

At its core, IoT bridges the physical and digital worlds. A traditional "thing" — a thermostat, a light bulb, a factory machine — becomes "smart" when it can sense its environment, process data, communicate over a network, and respond to commands or conditions automatically.

# A simple IoT concept in Python pseudocode
class SmartThermostat:
    def __init__(self, target_temp=22):
        self.target_temp = target_temp

    def read_temperature(self):
        # In reality: read from DHT22 sensor over GPIO
        return 18.5

    def decide_action(self):
        current = self.read_temperature()
        if current < self.target_temp:
            return "HEATER_ON"
        elif current > self.target_temp + 1:
            return "HEATER_OFF"
        return "HOLD"

thermostat = SmartThermostat(target_temp=22)
print(thermostat.decide_action())  # HEATER_ON

Brief History of IoT

The Four-Layer IoT Architecture

IoT systems are typically described in four layers:

┌─────────────────────────────────────────────┐
│         APPLICATION LAYER                   │
│   Dashboards · Analytics · Automation       │
├─────────────────────────────────────────────┤
│         PROCESSING / PLATFORM LAYER         │
│   Cloud (AWS IoT, Azure IoT) · Edge Server  │
├─────────────────────────────────────────────┤
│         NETWORK LAYER                       │
│   WiFi · BLE · Zigbee · LoRa · 4G/5G       │
├─────────────────────────────────────────────┤
│         PERCEPTION LAYER (Hardware)         │
│   Sensors · Actuators · Microcontrollers    │
└─────────────────────────────────────────────┘

Each layer has a specific responsibility:

• Perception — gather real-world data (temperature, motion, pressure)
• Network — transmit that data reliably and securely
• Processing — store, analyze, and make decisions
• Application — present insights and trigger actions

What Can You Build With IoT?

Why Python for IoT?

Python is one of the most popular IoT programming languages because:

# Python runs everywhere in the IoT stack

# 1. On a Raspberry Pi (full Python 3)
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)

# 2. On ESP32/ESP8266 (MicroPython)
from machine import Pin
led = Pin(2, Pin.OUT)

# 3. On the cloud (data pipelines, APIs)
import boto3  # AWS IoT
client = boto3.client('iot-data')

# 4. For data analysis
import pandas as pd
df = pd.read_csv('sensor_data.csv')
print(df['temperature'].mean())

IoT vs Traditional Computing

Key IoT Statistics (2025)

• ~18 billion IoT devices connected globally
• $1.1 trillion IoT market size projected by 2028
• 41.6 billion devices expected by 2030 (IDC)
• 70% of organizations have at least one IoT deployment
• Manufacturing is the largest adopter, followed by transportation and utilities

Summary

• IoT connects physical devices to the internet to enable sensing, communication, and automation
• Kevin Ashton coined the term in 1999; the ecosystem has exploded since
• The four-layer architecture: Perception → Network → Processing → Application
• Applications span smart homes, healthcare, industry, agriculture, and more
• Python is a first-class citizen across all layers of the IoT stack
• IoT differs from traditional software in power constraints, intermittent connectivity, and scale

In the next topic, we will explore the complete IoT ecosystem — hardware platforms, cloud services, and the tools that hold it all together.