Macworld contributor Brian Jepson isn't content with just connecting external drives, mice, scanners, and printers to his Mac—he wants to control custom hardware. He explains how to do just that with a microcontroller. Jepson writes:
To show you what's possible with microcontrollers and the Mac, I came up with a demonstration project that I call BreakTimer. This system enables your Mac to detect whether you're sitting in your chair and, if you've been sitting too long, to tell you it's time to get up and take a break.
Jepson uses the Arduino microcontroller board, which plays nice with the Mac and comes with software that lets you program it. Hit the link to see how he hooked up a seat sensor and the microcontroller to his Mac to issue break reminders.