Maria Paz is exploring the field of mood inputs by using your pulse as an input to control your environment. The sensor is sending out light that is reflected in the finger and back to the light sensitive sensor. As blood is pumping and flowing in the finger the amount of light received back alters. The output gives you the pulse of your body. Follow her progress in working on her final project Mood Tunnel on http://themoodtunnel.posterous.com/
Nintendo Wii introduced the Vitality sensor a few months ago, working as an input to measure your health and can be used in games.