Europa-List: Noncontact fuel level indicator

[Andrew Sarangan <asarangan@gmail.com>]

The fuel tank is translucent. One can clearly see the fuel level by
eye. So, it occurred to me why not build a fuel level sensor that
attaches to the outside of the tank? I recently built such a unit with
LED illuminators and detectors, and it works like a charm. It even
shows the waves when the fuel is sloshing around. Only question is,
how does the translucency of the tank change with time? If it becomes
totally opaque in a few years, then this won't work. I can post
further details of the device if anyone is interested.