I looked through he forums but I still have a tough time finding a recommendation for a flow meter that would work well with OpenSprinkler.
Anybody has a recommended piece of hardware that I should get?
If you search “water meter pulse output” on amazon you can find several choices. They usually have two wires coming out of the meter. There are brand names like EKM or DAE.
There are also smaller and cheaper ones that come with 3 wires — those are usually not very reliable and tend to generate too many pulses per second so I wouldn’t recommend them, although they are still usable with OpenSprinkler.