Rolling 24h accumulating measurement

Projects Programming
1

Hi

I have an electric motor that starts and stops every now and then. many times per day.

I log the the starts and stops and measure the run-time of the motor.

I would like to present how long the motor has been running in total, for the last 24 hours, at any given time. For instance, if I check the log right now, I would like to now how long time the auger has been running since the same time yesterday. If I check it in 1.5 hours again, it should be the same (but 1.5 hours later)

Any suggestions on how to implement this?
I am thinking I am not the first to do this, so there might be code for it somewhere :slight_smile:

The application is a house heating system with a pellet boiler, where I measure the run time of the auger feeding the pellet burner with pellets. I am running an ESP8266 hooked up to the burner and feeding a webpage via wifi/internet with stats from the burner.

2

Number of seconds since midnight.
Simple timestamp.

3

where do you log the data and what timeline do you use to remember the starts and stops moments ? do you have an RTC ? (and do you keep start time and duration or start time and stop time?)