As computer technology has evolved, there have been two groups of people: the hardware group that understands the machine, and the software group that codes in high-level programming languages. This book puts the two together by providing an understanding of the nuts and bolts of digital devices and implementing hardware operations by coding a microcontroller.We use the Arduino microcontroller, which is embraced by the world-wide maker community of well over 300,000 people of all ages and technical backgrounds. The projects start at ground level and scaffold upward to fun challenges.We begin with a background on digital circuitry and cover the operation of the Arduino microcontroller. From there, we examine digital logic gates, which are the building blocks of computer hardware, and see how they make decisions.