Hi All

I'm trying to build a counter which counts pulses from a energy meter, I would like to count as fast as possible.
I have tried a 3.5 and 3.6 found not much difference between the two. I have looked at the example video that Paul did, but the
difference being I'm trying to use an Optocoupler (6N139)

I have tried using both counting interupt's and the Freqcount.h library and haven't had much success in getting it to go really fast.

Just throwing it out there if anyone has done anything similar using an opto