The Raspberry Pi has traditionally been programmed using Python. Although this is a very powerful language, many programmers may not be familiar with it. C on the other hand is perhaps the most commonly used programming language and all embedded microcontrollers can be programmed using it. The C language is taught in most technical colleges and universities and almost all engineering students are familiar with using it with their projects. This book is about using the Raspberry Pi with C to develop a range of hardware-based projects. Two of the most popular C libraries, wiringPi and pigpio are used. The book starts with an introduction to C and most students and newcomers will find this chapter invaluable. Many projects are provided in the book, including using Wi-Fi and Bluetooth to establish communication with smartphones. Many sensor and hardware-based projects are included. Both wiringPi and pigpio libraries are used in all projects. Complete program listings are given with full explanations. All projects have been fully tested and work. The following hardware-based projects are provided in the book: - Using sensors - Using LCDs - I²C and SPI buses - Serial communication - Multitasking - External and timer interrupts - Using Wi-Fi - Webservers - Communicating with smartphones - Using Bluetooth - Sending data to the cloud Program listings of all Raspberry Pi projects developed in this book are available on the Elektor website. Readers can download and use these programs in their projects. Alternatively, they can customize them to suit their applications.