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Would it be possible?

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New Member
Hi i'm new to electro tech and a releative beginer to electronics.:oops:

I would apreciate your help with this, would it be possible to make a max rpm record/playback device using a PIC with the pulsein/out commands?

What sort of circuit would this require? is it even possible?

Any idea's or suggestions would be greatly appreciated.



New Member
Yes, it's possible.

You can use any PORTB pin to do this. Just generate an interrupt with every turn, and count the pulses. Calculate the time between two pulses and you're done.

Assuming your RPM meter will sense speeds up to 20000 RPM:

20000 RPM = 333 revolutions per second

And the period of the revolution would be 3 ms.

If you run the PIC with a 4MHz crystal, you will have an instruction every 1 us, and this will be your resolution

Hope that gets you started

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