N
NotMyRealName
...But what are you going to do with it?...
I will have to do a 'calibration' once. Or twice. Assume the meter reads 0 units on a full cylinder. End of cylinder say it reads 348 units. So i know a full cylinder contains about that much. So next cylinder would reach empty at around 696 units. Or instead of adding, maybe reset the meter to 0 each new cylinder.