Cycling down Mt. Zürich every morning during rush hour, I realised how dangerous it can be to take a hand off the handlebars to indicate a lane change. We used the physical computing module at University to solve these issues. The outcome was a helmet with inbuilt LEDs, controlled by a light sensor to automatically turn at night. The indicator lights react to a sideward nod of your head (accellerometers), also triggering feedback through vibrators in the straps.