So the four-4-US$12 flow sensors have turned up. The minimum measurable flow rate appears to be 1 litre a minute. To put this in perspective Bob Hawke (ex Australian Prime Minister) sculled a yard glass (1.4 litre) of beer in a record (for the time) 12 seconds.
In comparison irrigation “emitters” tend to be in the ranges of:
- 2,0 liters/hour – 1/2 gallon per hour
- 4,0 liters/hour – 1 gallon per hour
- 8,0 liters/hour – 2 gallons per hour
Now this will be per emitter so you will need around 8 times 8,0 liters/hour “emitter” in a line to get a 1 liter/minute flow by napkin scribbles. A whopping 30! 2,0 liters/hour “emitter” will be needed to get a 1 litre/minute flow in a line. Note, there may well be more than enough “emitter” to turn the paddle but that will depend upon the individual installations.
Not really a problem as the intention was to use this as a leak detector as the rate will be driven up but the leak, especially if your dog has dug up and chewed through a hidden hose, as evidenced by …
… mind you that one didn’t need a leak detector to find.
These sensors are advertised as low precision in any event so really not a problem. So this won’t be of use to meter your water usage.
I am playing with the idea of higher precision flow sensors – to set time-versus-budget constraints – but I will roll that in as a separate option as such a flow meter can likely go on the input rather than output lines, and as we are using MQTT the high precision flow-sensor can also be separate unit to the valve controller/line flow sensor.
All the signal integration will occur in the main host.