I have a project that I have been thinking about and need to us CO2 for it. What ways are there to measure the amount of CO2 left in a cylinder if its mounted to a moving object? I thought about the normal scale method but with bumps it wouldn't be accurate. You cant really measure pressure since it self regulates in a way and will change with temperature. The only other thing I have been able to come up with is measure the flow and come up with a calculation that a certain volume weighs so much but that seems like that would leave a pretty high margin of error. The only way I see to get close using that method is to fill your own tank that you know the weight on with a known weight of liquid co2 using a scale.