Identifying the Arduino COM Port on Windows

Connect your Arduino Uno to your computer via a USB cable.

Open the Device Manager by clicking the Start menu, right-clicking Computer (Vista) or My Computer (XP), and choosing Properties. On Windows XP, click Hardware and choose Device Manager. On Vista, click Device Manager (it appears in the list of tasks on the left of the window).

Look for the Arduino device in the list under Ports (COM & LPT). The Arduino will appear as Arduino UNO and will have a name like COM7, as shown in Figure 11-1.

NOTE

On some Windows machines, the COM port has a number greater than 9; this numbering creates some problems when Arduino is trying to communicate with it.