Arduino: A Quick-Start Guide, 2nd Edition

Using Serial Ports

Arduino makes many stand-alone applications—projects that do not involve any additional computers—possible. In such cases you need to connect the Arduino to a computer once to upload the software, and after that, it needs only a power supply. More often, people use the Arduino to enhance the capabilities of a computer using sensors or by giving access to additional hardware. Usually, you control external hardware via a serial port, so it is a good idea to learn how to communicate serially with the Arduino.

Although the standards for serial communication have changed over the past years (for example, we use USB today, and our computers no longer have RS232 connectors), the basic working principles remain the same. In the simplest ...