I’m logging voltage and current of electric appliances (eg. lights) in my use case, the idea being I’d like to calculate the daily energy consumption. Following are the concerns:

- How do I multiply voltage and current of each data point, and store it in a new field (Power)
- Let’s say the frequency of data collection is 5 minutes. How do I calculate the time difference (in minutes) between two successive data points? This would enable me to multiply power with time, and store the result as a new field (Energy).
- I want to calculate the energy consumption every day, and plot a daily profile of energy consumption. How do I segregate Date from the timestamp, and save it as a new field, so that I can reference the energy consumption by Date, and produce a plot.