Hi, I built a electrolytic cell that uses electricity to break water into hydrogen and oxygen. I am testing efficiency and need a way of calculating the average current draw and voltage drop over a period of time for the cell. I have some experience using Arduinos in projects but not much. I know I will have to take samples then use a function to calculate the average voltage and current. By the way the current is measured using a shunt so 1mv = 1amp. The voltage drop averages around 40 volts. I have researched some but am still very confused on adding memory to the arduino and outputting data via serial cable to a laptop. Any help would be much appreciated. Thanks in advance.