Oxygen Switch Gauge?

Has anyone done this gauge yet? I'm imagining a gauge for unpressurized planes that recognizes when you've been flying higher than X number of feet for X number of hours, and, if you haven't flipped the oxygen switch, it starts to make the screen get blurry or darker, and eventually crashes you if you don't recognize what is wrong and switch on your oxygen. Also, it keeps track of the amount of oxygen you have used, and, if you don't recharge the tanks, you eventually run out with applicable consequences.Thomas