ESP32 Web Server Monitor Temperature and Control a Relay Over Local Wi-Fi

ESP32 Web Server Monitor Temperature and Control a Relay over local Wi-Fi 

Introduction.
By utilizing sensors and relays it is possible to monitor environmental conditions such as temperature and humidity even when not close at hand. "Why would I want to do that?" you say... 
Imagine, if you will, the ability to automatically turn on/off fans or watering systems based on certain environmental conditions. Yes? An automated monitoring system can be implemented in your greenhouse to turn on/off pumps or fans based on the temperature and humidity. A similar system can also come in handy for the baby's room, for turning on a fan, or perhaps even the dog house, cat house and hen house, ensuring a comfortable and safe environment for your loved ones
This book will take you through setting up and coding the first step; monitoring the temperature and humidity to control the relay (the bit that does all the work). After that, you just need to connect the relay to you system for automation (not in this book)

What we are going to do.
In this book we are going to;
Build a breadboard circuit using the ESP32 low-cost, high performance microcontroller board. A DHT22 Temperature and Humidity Sensor, combined with a Relay and some jumper leads.
Install & set-up the Arduino IDE & Libraries we will be using.
Prepare and upload ESP32 code and support pages, for a WebSocket Web Server program serving an HTML page broadcasting temperature and humidity value to connected clients. As well as allowing switching of a Relay On/Off when we want, via any Web Browser on the local Wi-Fi network.
All developed under Windows 10/11 ( code available for download).
Sounds like something that might be useful, let's go.