It can be used on Windows, Linux and Android smartphones or tables. Adding additional pedals allows you to send more keystrokes. This project describes how to send and keys for two pedals, but you can use one pedal for one keystroke as well. Flip a page forward / backward in a PDF reader.The possibilities are endless! Some examples:
When you press the pedal with your foot, a keyboard keystroke will be send to your computer, smartphone or tablet over USB. This Instructable describes how to build a USB pedal with an Arduino Leonardo board.