Determine valve handle position

Hi all,

Any suggestions on the best way to determine the position of a ball valve? I'd like to use the existing valve which is similar to:

Can I mount something on the handle that would still allow it to be used in the normal fashion? I could live with a binary response (fully closed vs not fully closed), preferred would be 3 levels: Fully closed, fully open, somewhere in between. The valve would still be operated by hand, I just need to know the status of the valve elsewhere (e.g. if the engine is operating while this valve is closed, give a warning signal to the operator).

Suggestions on an inexpensive sensor I could use to send a signal to the Arduino?


You could use a potentiometer on a bracket that mounts it over the valve axis. The Arduino could then measure the valve position.

A microswitch that is closed when the valve is closed, in series with a switch that is closed when the engine is running, powering a lamp, seems to be all you need. How to arrange the 'engine running' switch is a question only you can answer, but it does not seem likely to be difficult.

I think the micro switch is exactly the route I was trying to think of. I'll give both a shot and see how it goes from there, thanks! The engine test should be pretty basic, not too worried about that one.