Grid Frequency Monitor - LCD version

Due to the issues I encountered with the 10 hour collection period of grid monitoring I decided I may need to do some filtering on the input of the Grid Frequency Monitor. I decided to try a .1 uF capacitor across the input of the switching transistor. I experimented with various capacitor values using Scopino to actually observe the wave shape. The selected value provided about a 3 ms rise time to the otherwise sharp leading edge of the square wave pulse.

I also did not want to have the computer connected for long term collection and wanted to rule out a serial transmission error so I modified the code to just drive a LCD with my Arduino. The LCD is a 16 character display. The left half always reads the current grid frequency and the right half alternates between the uptime in days, hours, minutes then the lowest frequency sampled followed by the highest.

I ran it over night for over 12 hours and I did not see the issue, however while setting up to take the pictures of the display I some how glitched it and it was reading over 100 hz! I think the prototype board can generate noise if bumped. If I can run it for several days with no issues I will solder up a more permanent probe board. The original code had accumulated offset in ms, sec, etc also which is interesting from the stability of the grid stand-point as the grid drives the old clock with a synchronous motors so I will add that back to the code to see that drift over time.