I have an Arduino UNO R3. It seems to be very sensitive to EMI. I have an HV (1400V) pulse circuit with a voltage divider which I hook up to the Arduino to measure the voltage of the 1400V cap bank. It mostly works, until the Arduino resets.
In this video I show how its outputting to the serial console the results of an analogread. There is nothing hooked up to the Arduino at first so the numbers shown in the serial window are just random. I then plug in the ground/negative side of the voltage divider to the Arduino. thats it. You'll see after a few pulses it freezes. Does this all the time. Will a flyback diode on my HV transformer stop backemf? is it backemf that is doing this or EMI from the HV transformer. I've had the Arduino freeze with nothing hooked up to it too at all, which leads me to believe EMI (through the air). But 99% of the times its when I hook something up to a pin. Why is the Arduino so sensitive? I find it flaky at best. I've tried two UNO's and two laptops, always the same instability.