Alan B. Pearce wrote:
>
> >No steps would work so long as the transistion from one step to another is
> >good and repeatable. Seems to me like your solution would work fine in this
> >case. Any info on the mechanical construction of this (like width of rod,
> >how deep to make each step ec.)
>
> I do not have any direct experience with the method, but heard of it being used for fluid level, I think it was in petrol tanks, where it was important to have no electric's inside the tank.
>
> Time for some ASCII art
>
> ------\_________
>                 \---------\_________
>                                     \
>                             ________/
>        _________/----------/
> ------/
>
> If you get the idea. The LED and sensor (e.g. a reflective sensor unit) would be looking down the rod from the left hand end. each step causes some light to be reflected back, and the liquid covering each step fouls up the reflection coefficient of that step, meaning light does not get reflected back.
>
> If you have access to a suitable lathe you may wish to try turning a piece of Perspex rod to try out the idea. The other trick which may work better for you, as I envisage the rod being on a slope inside the tank, is to use a rectangular rod, and steadily mill away steps on one side only. It may require some experimentation to determine if you get better results with the steps on the top or bottom side in this case.
>
> happy experimenting
>
> --

I think that is a really clever idea!

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