I did one once (unreleased). Apart from the problems that you always run into when you do loops (here a recurring 1 second timer), it also wasn't terribly useful as the values would jump around too much. I didn't include any code to normalize the values over time, I just displayed pure damage per second, i.e. dps would jump from 0 to 20k and back all the time. But theoretically you could store the data internally and normalize it.
In the end I just found ACT easier and much better to use and I scrapped the project.
