Hi DebutPic

The first question to ask is that one : you want to show 5 turns/min resolution , ok, BUT at which speed ???

Where do you want to measure these RPMs ???

There are other methods for RPM Measuring ... but depends on the use you want to do ... and mostly the pulse freq.

Ceci dit, un joyeux pneu à toi aussi !!! ( a happy good year ... )

Alain