View source for MDM331AID/Experiment 5

= Experiment: Wi-Fi Connectivity and TCP/IP-Based Sensor Data Transmission Using ESP32 =

== Aim ==

To configure and implement an IoT device using ESP32 to connect to a Wi-Fi network and transmit temperature and humidity data from a DHT11 sensor to a remote computer using TCP/IP communication.

== Objectives ==

* To understand Wi-Fi connectivity in IoT devices.
* To interface a DHT11 temperature and humidity sensor with ESP32.
* To understand TCP/IP communication and socket programming.
* To establish a TCP connection between an ESP32 and a remote computer.
* To transmit and receive sensor data over a Wi-Fi network.

== Components Required ==

{| class="wikitable"
|-
! Sr. No.
! Component
! Quantity
|-
| 1
| ESP32 Development Board (COG-E32)
| 1
|-
| 2
| DHT11 Temperature and Humidity Sensor (COG-MSBA)
| 1
|-
| 3
| USB Data Cable
| 1
|-
| 4
| Patch Cords
| As required
|-
| 5
| Computer with Arduino IDE
| 1
|-
| 6
| Remote Computer connected to the same Wi-Fi network
| 1
|-
| 7
| Wi-Fi Network
| 1
|}

== Theory ==

=== Internet of Things (IoT) Device ===

An IoT device is a physical device equipped with sensors, processing capabilities, and communication interfaces. It collects data from its surroundings and transmits the information to another device or a remote server.

In this experiment, the ESP32 acts as the IoT device. The DHT11 sensor collects temperature and humidity readings, which are transmitted to a remote computer.

=== Wi-Fi Connectivity ===

Wi-Fi is a wireless networking technology based on IEEE 802.11 standards. It allows IoT devices to connect to a local wireless network and exchange information with other devices.

The ESP32 has built-in Wi-Fi connectivity, making it suitable for IoT communication experiments without requiring an additional Wi-Fi module.

=== TCP/IP Communication ===

TCP/IP is a protocol suite used for communication between devices over a network.

* '''IP (Internet Protocol):''' Provides addressing and routing of data packets between devices.
* '''TCP (Transmission Control Protocol):''' Provides reliable, ordered, connection-oriented data delivery.
* '''Socket:''' A software interface used by applications to send and receive data over a network.

In this experiment, the remote computer runs a TCP server that listens for incoming connections. The ESP32 acts as a TCP client and sends sensor readings to the server.

The basic communication flow is:

<pre>
DHT11 Sensor
     |
     v
   ESP32
     |
     v
 Wi-Fi Network
     |
     v
Remote Computer
     |
     v
 TCP Server
</pre>

=== DHT11 Sensor ===

The DHT11 is a digital temperature and humidity sensor. It provides temperature and relative humidity readings through a single digital data interface.

Typical measurement ranges are:

* Temperature: 0 C to 50 C.
* Relative humidity: 20 percent to 90 percent.

The DHT11 is suitable for basic environmental monitoring demonstrations. Its accuracy and measurement range are limited compared with more advanced sensors.

=== System Architecture ===

<pre>
       DHT11 Sensor
            |
            v
     +----------------+
     |     ESP32      |
     |   TCP Client   |
     +----------------+
            |
        Wi-Fi Network
            |
            v
     +----------------+
     | Remote Computer|
     |   TCP Server   |
     +----------------+
            |
            v
      Display Sensor
           Data
</pre>

== Pin Connections ==

{| class="wikitable"
|-
! ESP32 Pin
! DHT11 Pin
! Description
|-
| 3V3
| VCC
| Sensor power supply
|-
| GPIO 4
| DATA
| Digital data interface
|-
| GND
| GND
| Common ground
|}

'''Note:''' The connections assume a compatible DHT11 module with clearly identified VCC, DATA, and GND pins. Verify the actual sensor-board pinout before making the connections.

== Software Requirements ==

=== ESP32 ===

* Arduino IDE
* ESP32 board support package
* DHT sensor library
* Wi-Fi library included with the ESP32 board package

=== Remote Computer ===

* Python 3
* TCP server program
* Wi-Fi connection
* Network access from the ESP32

== Program 1: TCP Server on Remote Computer ==

The remote computer acts as a TCP server. It listens on port 5000 and displays the temperature and humidity data received from the ESP32.

Download the program:

[[Media:IoT_TCP_DHT11_Programs.zip|TCP Server and ESP32 Client Programs ZIP]]

== Program 2: ESP32 TCP Client ==

The ESP32 connects to the Wi-Fi network, reads the DHT11 sensor values, and sends the readings to the remote computer using TCP.

Download the program:

[[Media:IoT_TCP_DHT11_Programs.zip|ESP32 TCP Client Program]]

== Procedure ==

=== Step 1: Configure the Remote Computer ===

# Connect the remote computer to the Wi-Fi network.
# Find the local IP address of the remote computer using the appropriate network command.
# Replace the example IP address in the ESP32 client program with the remote computer's actual IP address.
# Save the TCP server program as tcp_server.py.
# Run the server using Python:

<syntaxhighlight lang="bash">
python tcp_server.py
</syntaxhighlight>

# Ensure that the firewall allows incoming TCP connections on port 5000.
# Keep the TCP server running while testing the ESP32.

=== Step 2: Configure ESP32 ===

# Connect the DHT11 sensor to the ESP32 using the specified pin connections.
# Open Arduino IDE.
# Install the DHT sensor library if it is not already installed.
# Enter the Wi-Fi SSID and password in the ESP32 program.
# Enter the remote computer's IP address in the ESP32 program.
# Enter the TCP server port number in the ESP32 program.
# Select the appropriate ESP32 board and COM port.
# Upload the program.
# Open the Serial Monitor at 115200 baud.
# Observe the Wi-Fi connection status.
# Observe the TCP connection status.
# Observe the temperature and humidity values being transmitted.

=== Step 3: Verify TCP/IP Communication ===

# Check that the remote computer reports an incoming TCP connection.
# Observe the temperature and humidity data received by the TCP server.
# Compare the transmitted values with the sensor readings displayed by the ESP32.
# Verify that multiple sensor readings are received by the server.
# Stop the ESP32 program or disconnect the device.
# Observe the disconnection message on the TCP server.

== Observations ==

{| class="wikitable"
|-
! Sr. No.
! Temperature (C)
! Relative Humidity (percent)
! Transmission Status
|-
| 1
| Record measured value
| Record measured value
| Successful / Failed
|-
| 2
| Record measured value
| Record measured value
| Successful / Failed
|-
| 3
| Record measured value
| Record measured value
| Successful / Failed
|}

'''Expected output on the remote computer:'''

<pre>
TCP Server started
Waiting for ESP32 connection...
Connected by: ('192.168.1.105', 54321)
Received: Temperature: 28.0 C, Humidity: 65.0 %
Received: Temperature: 28.0 C, Humidity: 64.0 %
Received: Temperature: 29.0 C, Humidity: 64.0 %
</pre>

The above values and IP addresses are illustrative examples, not actual measurements.

== Result ==

An IoT application was implemented using an ESP32 and DHT11 sensor. The ESP32 successfully connected to a Wi-Fi network and transmitted temperature and humidity readings to a remote computer using TCP/IP socket communication.

== Viva Questions ==

# What is the role of Wi-Fi in an IoT application?
# What is TCP?
# What is the difference between TCP and UDP?
# What is an IP address?
# What is a TCP socket?
# What is the difference between a TCP client and a TCP server?
# Why is TCP considered a reliable communication protocol?
# What is the function of the bind() function in Python socket programming?
# What is the purpose of the listen() function?
# What is the purpose of the accept() function?
# What is the function of sendall() in Python?
# Why should the remote computer's IP address be configured in the ESP32?
# What is the difference between a local IP address and a public IP address?
# Why is port 5000 used in this experiment?
# How can the application be extended to store sensor readings in a database or cloud platform?