E Smoke 2x

E-cigarettes I've seen so far give no indication how much battery capacity or nicotine cartridge capacity is left. Some of the rebounds addressed that issue by presenting the cigarette as, essentially, a battery indicator.

Following on that idea and in spirit of simulating "the real thing", what if the "tobacco" side would give an indication of how much longer smoker can enjoy the cigarette by colouring the "burned" part in grey or black e-ink and lighting a LED to indicate the current charge.