I see some cheap Hall effect water flow sensors available (< $20) for 1 to 60 L/min range (which doesn’t help for very low flow drip or very high demand sprinklers but should cover most cases). However, these just put out an electrical impulse. One would still need to process those signals and display the info. But it has me wondering if there’s not a product idea here 🙂 It probably has been done. I just haven’t found it yet. Altogether I figure you can probably have flow data sent directly to the OS for < $40 but someone’s got to do it.
Hmmm… would that be interesting to people? I can look at it.