If work is getting to you, or at the end of the day you just can't relax - consider making yourself a "Relaxino". Created by Arduino forum member "trendski", it's a biofeedback device that can detect your heart rate using a clip-on ear sensor. As the system detects your heart beats, it displays whether your heart rate is above, below or just around a certain level with LEDs - thus giving you a method of focusing on and reducing your heart rate.
If you decide to make such a device, ensure you power the system from a battery and not the mains power. For more information and the sketch, click here to visit the Arduino forum post. And for more, we're on twitter and Google+, so follow us for news and product updates as well.