Timespan between two events

May 26 2013 2:26 AM

I receive a message from serial port that is passed to a variable once every few seconds. The message is generated by a microprocessor and it is basically a simple string containing "1/r" which represent one complete turn of a motor (every time a microswitch is pressed, the micro prints "1/r) on the serial port). In order to show in a text box the revolution per minute of such motor, based on the time interval between the update of the variable, I would like to implement a timespan method. I should therefore obtain the time elapsed between the start and the end of a turn and return the result for further actions to the original method.

This is what I have done so far but does not work:

public void CalcolaRPM (string giriRicevuti, out double RPM)

{

Stopwatch stopWatch = new Stopwatch();

stopWatch.Start();

{

if (giriRicevuti == "1/r")

{

stopWatch.Stop();

}

double elapsedT = stopWatch.ElapsedMilliseconds;

stopWatch.Restart();