Frequency to Microprocessor input.

MikeMl said:

To implement a tach, you have two choices: count events per unit time, or measure the period between events using a high frequency clock (like the cpu clock of a microprocessor). Doing the former with any significant resolution means waiting a relatively long time between updates (like a second per update). Doing the latter means you can get higher resolution in a shorter time (like the interval between successive power strokes). Doing the latter, however, requires that you do a division to get the RPM:

f=k/period, where k is a constant.

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Huttojb1 said:

Hey Spec,

Sorry the diagram wasn't viewable on my phone last night so didn't see you had posted it.

Thanks ever so much, I will need to source the 6N139, but will definitely try the design for my solution.

Will definitely get back to you with the results.

Thanks again, Jason.

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Huttojb1 said:

Spec, all components ordered and should be here Monday.

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Huttojb1 said:

After earthing pin 3 it all magically started to work.

See results.

Would like to thank the people who have helped me on this.

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