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Topic: Frequency Measurement Library Zero Frequency (Read 454 times) previous topic - next topic

matinzk

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.

MarkT

You want to use a different technique from that library (which is measuring the period).  You want to measure the zero-crossings per second instead.   Simplest way is to count each zero crossing in a variable and then every second (use the blinkWithoutDelay technique) note the change in that variable from the last time.
[ I won't respond to messages, use the forum please ]

matinzk

Thanks for your reply.

I'm not sure how to do that to be honest  :~

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