It's rush hour, and you're headed due West on your evening commute -- the sun burning holes in your eyes. You could flip down a window visor, trading your field of view for visibility. Or, with a prototype shown off at Intel's 2010 International Science and Engineering Fair, you could simply let the windshield darken on its own. Two San Diego students (both accustomed to copious amounts of sunshine) rigged a Toyota Prius to do just that by stringing up electrochromic panels, which dim when voltage is applied. The trick is figuring out when and where to apply it, because when the sun is shining the panels them
