The best solution for this is probably to use Kapacitor with a script something like this…
stream
|from()
.database('door')
.measurement('door')
|stateDuration(lambda: "value" == FALSE)
.unit(1s)
|influxDBOut()
.database('door')
.retentionPolicy('autogen')
.measurement('door_open')
However, as noted by @michael on this thread, you’ll need to sample and write the sate of the door more often than just on state changes in order for it to calculate state duration.
