Book Image

ESP8266 Home Automation Projects

By : Catalin Batrinu, Constantin Tambrea
Book Image

ESP8266 Home Automation Projects

By: Catalin Batrinu, Constantin Tambrea

Overview of this book

The ESP8266 is a low-cost yet powerful Wi-Fi chip that is becoming more popular at an alarming rate, and people have adopted it to create interesting projects. With this book, you will learn to create and program home automation projects using the ESP8266 Wi-Fi chip. You will learn how to build a thermostat to measure and adjust the temperature accordingly and how to build a security system using the ESP8266. Furthermore, you will design a complete home automation system from sensor to your own cloud. You will touch base on data monitoring, controlling appliances, and security aspects. By the end of the book, you will understand how to completely control and monitor your home from the cloud and from a mobile application. You will be familiar with the capabilities of the ESP8266 and will have successfully designed a complete ready-to-sell home automated system.
Table of Contents (16 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback
Building a Home Thermostat with the ESP8266
Using ESP8266 to Build a Security System

Passive infrared sensor

PIR is the most common sensor used in the indoor and outdoor alarm systems. It is also used in automated doors and automated lights systems.

How PIRs work

The functionality of the PIR sensor is based on radiation emitted by human bodies. Objects generate heat as infrared radiation and those objects include animals and the human body whose radiation is strongest at a wavelength of 9.4 μm.

When a human passes the front of the sensor, the temperature from the PIR sensor point of view changes from the background value to the human value. The sensor detects this change in the infrared radiation and changes its output voltage, signaling the detection.

To increase the sensitivity of the PIR sensor, a Fresnel lens is mounted in front of it. A sensor is in fact a FET transistor with a source pin connected with a pull down to ground. We can see this setup in the following figure:

In the following image, we can see a Fresnel lens made from plastic:

The sensor itself is located under...