Digital Ins and Outs

Abstract

So far in our discussion of programming the Arduino microcontroller, we have generally glossed over the physical interactions of turning things on and off and sensing the world around us that make programming microcontrollers so much fun. Now it’s time to fix that. Programming a microcontroller can be rather unique because of its ability to easily turn on and off motors, lights, and other actuators, as well as read from switches and sensors. This is possible on the Arduino Uno by using its 20 input and output (I/O) pins, each having different functions that can be configured in software-including input, output, analog to digital conversion (ADC), and analog output, more accurately called pulse width modulation (PWM)). This chapter will take as its focus the various digital input and output functions available and how to interface the needed hardware to make them work.