The Arduino Uno is an open-source microcontroller development system encompassing hardware, an Integrated Development Environment (IDE), and a vast number of libraries. It is supported by an enormous community of programmers, electronic engineers, enthusiasts, and academics. The libraries in particular really smooth Arduino programming and reduce programming time. What's more, the libraries greatly facilitate testing your programs since most come fully tested and working.The Raspberry Pi 4 can be used in many applications such as audio and video media devices. It also works in industrial controllers, robotics, games, and in many domestic and commercial applications. The Raspberry Pi 4 also offers Wi-Fi and Bluetooth capability which makes it great for remote and Internet-based control and monitoring applications.This book is about using both the Raspberry Pi 4 and the Arduino Uno in PID-based automatic control applications. The book starts with basic theory of the control systems and f