I am using the Frequency Measurement Library: http://interface.khm.de/index.php/lab/experiments/frequency-measurement-library/

I am trying to measure frequecy from 0-500 To then connect to my RPM and speed frequency signal wires on my car to convert the frequency values to the correct speed and RPM values.

The problem I have is that when RPM is 0 or speed is 0 the library either doesn't give me anything or gives random values. How can I measure 0 frequency? Or in other words set frequency at zero when there are no counts?

I don't have to use this particular library either.

Any help is appreciated.

Thanks.