A lot of governments (at least in Australia) ask their residents to use 4 minute egg-timers in the shower to save water. Well I like idea of LEDs that show water usage much better. For every 5 litres that that goes own the drain, a new LED on the scale lights up.
Not only is this more interesting than watching an egg-timer, it’d be much more accurate too (measuring time assumes everyone is using the same water pressure).
Courtesy of infothestics.