Course: 10. Internet of Things (IoT)

What & Why

What is IoT and Why It Matters in Robotics

Internet of Things (IoT) refers to a network of physical devices—like sensors, machines, or robots—that are connected to the internet and can send or receive data. These smart devices can collect, share, and act on data in real time.

Select activity Key Concepts
🔹 Key Concepts

Things: Devices like robots, sensors, lights, and appliances.

Internet: The connection that allows these devices to communicate globally.

Data: The real-time information that these devices collect, send, and act upon.

💡 Why Does IoT Matter in Robotics?

Robots become smarter when they can access cloud data.

IoT helps robots interact with users and other machines over long distances.

Real-time updates make robots adaptable and responsive to changes.
Select activity Everyday Examples
📦 Everyday Examples of IoT

Smart thermostats adjusting room temperature based on user behavior

Wearable fitness trackers sending health data to mobile apps

Smart fridges that send alerts when food items are low

🤖 IoT in Robotics

Remote monitoring of robot activities (e.g., surveillance bots)

Sending sensor data (e.g., temperature, motion) to the cloud

Receiving commands from smartphones or cloud services

Summary: IoT makes robots smarter, connected, and more useful. In the next sections, we will explore the hardware that enables IoT in robotics.

New section

Section 2: Introducing ESP32 and NodeMCU

In the world of IoT-enabled robotics, not all microcontrollers are equal. While Arduino Uno is excellent for learning and prototyping, devices like ESP32 and NodeMCU are better suited for projects that require Wi-Fi connectivity and cloud communication. These boards bring more processing power, more memory, and built-in wireless features.

🔍 What is ESP32?

The ESP32 is a robust microcontroller with integrated Wi-Fi and Bluetooth capabilities. It is developed by Espressif Systems and is widely used in both DIY and professional-grade IoT solutions.

Dual-core processor running up to 240 MHz
Over 30 GPIO pins for flexible sensor and motor connections
Built-in support for Wi-Fi and Bluetooth (Classic and BLE)
Touch sensors, hardware PWM, and ADC/DAC functionalities
More SRAM and flash memory compared to Arduino Uno

🔍 What is NodeMCU (ESP8266)?

NodeMCU is based on the ESP8266 chip. It is a low-cost microcontroller board with built-in Wi-Fi that is ideal for smaller IoT projects or beginners entering the wireless world.

Single-core processor running up to 160 MHz
Fewer GPIO pins than ESP32, generally 10–12 usable
Supports only Wi-Fi, no Bluetooth
Compact and cost-effective
Programmed using the Arduino IDE or Lua scripting

📊 ESP32 vs. NodeMCU Comparison

Feature	ESP32	NodeMCU (ESP8266)
Wi-Fi	Yes	Yes
Bluetooth	Yes (Classic + BLE)	No
Processor	Dual-core, 240 MHz	Single-core, 80–160 MHz
GPIO Pins	30+	10–12 usable
ADC Support	Multiple ADC channels	1 ADC channel
Memory (RAM)	520 KB SRAM	160 KB
Flash	Up to 16 MB	Typically 4 MB
Price (approx)	INR 300–400	INR 200–300

Select activity Programming
⚙️ Programming ESP Boards with Arduino IDE

Both ESP32 and NodeMCU can be programmed using the Arduino IDE. However, some setup steps are needed:

Install the required board definitions via Board Manager

Select the correct board and port under Tools

Use USB to micro-USB cable for uploading code

Once set up, you can write sketches using C/C++, just like you do for an Arduino Uno. You can also use libraries like WiFi.h and HTTPClient.h for internet communication.

💬 Real-World Use Cases

ESP32: Cloud-connected robots, remote monitoring systems, wearable devices

NodeMCU: Basic IoT sensors, smart lights, simple remote control bots

🧠 Choosing the Right Board

Use ESP32 if your project requires Bluetooth, more GPIOs, or high-speed processing

Use NodeMCU for simple IoT tasks where cost and compact size are a priority

Data to Cloud

Sending Sensor Data to the Cloud (e.g., ThingSpeak)

One of the most exciting capabilities of IoT in robotics is sending live sensor data to the cloud, where it can be viewed, stored, and analyzed remotely. In this section, we will explore how to transmit data from ESP32 or NodeMCU to a cloud service like ThingSpeak.

Select activity ThingSpeak
🌐 What is ThingSpeak?

ThingSpeak is a cloud-based platform provided by MathWorks that allows devices to send data using HTTP protocols. It offers easy graphing, public/private channels, and MATLAB-based data analysis tools.

Free for personal use with limited updates per day

Supports HTTP and MQTT protocols

Real-time chart plotting and analytics

Used widely for temperature monitoring, environment sensing, etc.

🛠️ What You Need

ESP32 or NodeMCU microcontroller

Wi-Fi connection

Sensor (e.g., DHT11 for temperature/humidity)

ThingSpeak account (https://thingspeak.com)

📶 Setting Up a ThingSpeak Channel

Create a free ThingSpeak account and log in.

Click on "Channels" > "New Channel".

Give a name (e.g., WeatherData), and enable the fields you want (e.g., Field1: Temperature, Field2: Humidity).

Save the channel and note down your Write API Key from the API Keys tab.

🔌 Circuit Setup

Example: DHT11 sensor with ESP32

VCC → 3.3V

GND → GND

Data → GPIO 4

🧑‍💻 Sample Code to Send Data to ThingSpeak


// Required Libraries
#include <WiFi.h>
#include <HTTPClient.h>
#include "DHT.h"

// Wi-Fi Credentials
const char* ssid = "YourWiFiSSID";
const char* password = "YourWiFiPassword";

// ThingSpeak Settings
const char* server = "http://api.thingspeak.com/update";
String apiKey = "YOUR_WRITE_API_KEY";

// DHT Sensor Settings
#define DHTPIN 4
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  dht.begin();

  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");
}

void loop() {
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  if (isnan(temp) || isnan(hum)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = server + String("?api_key=") + apiKey +
                 "&field1=" + String(temp) +
                 "&field2=" + String(hum);

    http.begin(url);
    int httpCode = http.GET();
    if (httpCode > 0) {
      Serial.println("Data sent successfully");
    } else {
      Serial.println("Error sending data");
    }
    http.end();
  }

  delay(15000); // Wait 15 seconds before next update
}

📊 Viewing Your Data

After running the sketch, open your ThingSpeak channel. You will see real-time graphs under each field that you've updated from your ESP board. These are auto-generated and updated every 15 seconds (or based on your delay).

Select activity Use Cases
💡 Use Cases

Environment monitoring robots that upload data every few minutes

Health robots that log temperature/humidity in a remote room

Weather bots that stream live updates to a dashboard

⚠️ Tips & Troubleshooting

Ensure correct Wi-Fi SSID and password

Double-check your ThingSpeak Write API Key

Use serial monitor for debugging network or sensor errors

Observe ThingSpeak update limits: 1 update every 15 seconds for free accounts

Lightweight Messaging

MQTT Basics – Lightweight Messaging for IoT

MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol widely used in IoT systems. It allows devices like sensors, robots, and microcontrollers to communicate over the internet with low bandwidth and power usage.

Select activity What-Why-How
🌐 What is MQTT?

MQTT is a publish-subscribe protocol. Instead of sending data directly between devices, all communication happens through a central broker (like a post office).

🧩 How MQTT Works

Broker: The central server that handles messages

Publisher: A device (e.g. ESP32) that sends data

Subscriber: A device or app that receives data

Topic: A channel or label used to organize messages (like /weather/temp)

Example: Your ESP32 publishes temperature data to the topic /robot/weather/temp. A mobile app subscribes to that topic and displays the latest temperature reading.

📦 Why Use MQTT?

Low bandwidth – ideal for IoT devices

Reliable – even over spotty Wi-Fi

Flexible – one message can be received by many devices

🔧 MQTT Terminology at a Glance

Term	Meaning
Broker	Server that manages all messages
Client	Any device connected to broker (ESP32, mobile app, etc.)
Publish	Send message to broker under a topic
Subscribe	Listen for messages on a specific topic
Topic	Label for organizing messages (e.g. /robot/temp)

💻 Sample Code (ESP32 Publishing Data)

#include <WiFi.h>
#include <PubSubClient.h>

const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  client.setServer(mqtt_server, 1883);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // Publish data
  client.publish("/robot/weather/temp", "28.5");
  delay(5000); // send every 5 seconds
}

void reconnect() {
  while (!client.connected()) {
    if (client.connect("ESP32Client")) {
      client.subscribe("/robot/commands");
    } else {
      delay(2000);
    }
  }
}

⚠️ Note

Use public MQTT brokers like broker.hivemq.com for testing
Always keep topic names clear and structured (e.g., /robot/status)
For production use, secure brokers and authentication are recommended

Project: IoT-Based Weather Bot

IoT-Based Weather Bot

In this hands-on project, you will build an Internet-connected weather bot using an ESP32 or NodeMCU. The bot will measure environmental data (like temperature and humidity) and send it to the cloud in real time for monitoring and visualization.

Select activity Project Details
🎯 Project Goals

Use a DHT11 or DHT22 sensor to measure temperature and humidity

Connect your ESP32/NodeMCU to Wi-Fi

Publish sensor data to the cloud using MQTT or ThingSpeak

Visualize the live data on a dashboard

🔌 Components Needed

ESP32 or NodeMCU board

DHT11 or DHT22 sensor

Jumper wires and breadboard

USB cable

Wi-Fi access

🧠 Circuit Diagram

Connect the DHT sensor to your ESP32 as follows:

DHT Sensor ESP32

VCC 3.3V

GND GND

DATA D4 (GPIO4)

DHT Sensor	ESP32
VCC	3.3V
GND	GND
DATA	D4 (GPIO4)

💻 Sample Code (Sending Data to MQTT Broker)

#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>

#define DHTPIN 4
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  dht.begin();

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  client.setServer(mqtt_server, 1883);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  if (!isnan(temp) && !isnan(hum)) {
    char tempStr[8];
    char humStr[8];
    dtostrf(temp, 1, 2, tempStr);
    dtostrf(hum, 1, 2, humStr);

    client.publish("/weatherbot/temp", tempStr);
    client.publish("/weatherbot/humidity", humStr);
  }

  delay(5000);
}

void reconnect() {
  while (!client.connected()) {
    if (client.connect("WeatherBotClient")) {
      client.subscribe("/weatherbot/commands");
    } else {
      delay(2000);
    }
  }
}

Select activity Visualizing
📊 Visualizing Data

Using ThingSpeak: Create a free account and channel, then use HTTP POST to send data from ESP32

Using MQTT Dashboard App: Subscribe to topics like /weatherbot/temp to view real-time data on your phone

🛠️ Optional Enhancements

Add an OLED display to show live data on the robot

Use IFTTT to trigger alerts if temperature goes above a limit

Send data to Google Sheets via webhook

✅ Key Takeaways

You can build real-time, connected devices with very basic components

MQTT and cloud services like ThingSpeak make data sharing simple

This weather bot is a great foundation for more advanced IoT automation

Summary and Quiz

You have now explored the powerful world of IoT and how it transforms everyday robots into smart, connected systems. From understanding what IoT means to building a live data-streaming weather bot, you have worked with ESP32, MQTT, and cloud platforms like ThingSpeak. You learned how to gather sensor data, push it online, and visualize it in real time. This foundation is essential for advanced applications like remote monitoring, automation, and smart robotics. Let’s now test your understanding through a quick recap quiz!

Select activity Quiz

Quiz

Section outline

What & Why

What is IoT and Why It Matters in Robotics

🔹 Key Concepts

💡 Why Does IoT Matter in Robotics?

📦 Everyday Examples of IoT

🤖 IoT in Robotics

New section

Section 2: Introducing ESP32 and NodeMCU

🔍 What is ESP32?

🔍 What is NodeMCU (ESP8266)?

📊 ESP32 vs. NodeMCU Comparison

⚙️ Programming ESP Boards with Arduino IDE

💬 Real-World Use Cases

🧠 Choosing the Right Board

Data to Cloud

Sending Sensor Data to the Cloud (e.g., ThingSpeak)

🌐 What is ThingSpeak?

🛠️ What You Need

📶 Setting Up a ThingSpeak Channel

🔌 Circuit Setup

🧑‍💻 Sample Code to Send Data to ThingSpeak

📊 Viewing Your Data

💡 Use Cases

⚠️ Tips & Troubleshooting

Lightweight Messaging

MQTT Basics – Lightweight Messaging for IoT

🌐 What is MQTT?

🧩 How MQTT Works

📦 Why Use MQTT?

🔧 MQTT Terminology at a Glance

💻 Sample Code (ESP32 Publishing Data)

⚠️ Note

Project: IoT-Based Weather Bot

IoT-Based Weather Bot

🎯 Project Goals

🔌 Components Needed

🧠 Circuit Diagram

💻 Sample Code (Sending Data to MQTT Broker)

📊 Visualizing Data

🛠️ Optional Enhancements

✅ Key Takeaways

Summary and Quiz