"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 feedback control. Working and tested projects are given for controlling real-life systems using PID controllers. The open-loop step time response, tuning the PID parameters, and the closed-loop time response of the developed systems are discussed together with the block diagrams, circuit diagrams, PID controller algorithms, and the full program listings for both the Raspberry Pi and the Arduino Uno.The projects given in the book aim to teach the theory and applications of PID controllers and can be modified easily as desired for other applications. The projects given for the Raspberry Pi 4 should work with all other models of Raspberry Pi family.The book covers the following topics:Open-loop and closed-loop control systemsAnalog and digital sensorsTransfer functions and continuous-time systemsFirst-order and second-order system time responsesDiscrete-time digital systemsContinuous-time PID controllersDiscrete-time PID controllersON-OFF temperature control with Raspberry Pi and Arduino UnoPID-based temperature control with Raspberry Pi and Arduino UnoPID-based DC motor control with Raspberry Pi and Arduino UnoPID-based water level control with Raspberry Pi and Arduino UnoPID-based LED-LDR brightness control with Raspberry Pi and Arduino Uno". [4e de couv.]