I've been writing a rule when it occurred to me that a useful app would fit the bill.
I have a number of motion sensors of differing brands. It would be great if I could run an app that gave back a report by taking the active to not active timer of each of my sensors for review.
Obviously it's not a daily use thing - more of an informational task.
Right now, I've a rule that has a button trigger - it then waits for a device to go motion active, logs the time, then sets a trigger to log the time when it goes deactive. subtract the two and you get your 'motion active length' value for a specific device.
I haven't figured out how to store seconds (don't need mills) - so currently my rule only shows minutes - so work to be done. but anyway - if anyone is bored....!