I think post# 2 is your best and easiest bet to achieve what you want to do.
Why do you have a check valve as indicated in your diagram? If the water main already has a check valve a 2nd one in the line does not make much sense.
I want the pressure to stay high when the irrigation turns on, if the irrigation turns on and there is no check valve there then the pressure sensor would think the house is using water and close the valve to the irrigation.
Well that is no fun. I don't want to be turning the valve manually a few times per night when someone uses the shower or dishwasher then opening it when they are not using the water.
The valve I am looking to use is servo/stepper driven ball valve. The valve remains in its current state if there is no signal sent.
I don't blame you. I thought you said it does not matter if the irrigation starves for a couple of days.
You indicated that the irrigation does not really matter, so the manual ball valve would just be a set it and forget it type of thing. So no adjustments needed.
I would think you need a separate power supply for it. Then the program could be as simple as analog read an inline pressure sensor of your choosing and map it to the servo control.
Yeah, I was just outlining that its not overly important that if the irrigation doesn't get water for a period of time, the yard would be okay.
I was thinking some sort of controller, relays, external 24v power supply, pressure sensor, motorized valve. But was initially wanting to use Arduino of some sorts.
The program seems as simple or complicated as YOU want it to be.
If it was my project at my house I would power the ball valve 24/7 from it's own power source (no relays needed) and program in an alarm condition to indicate a potential leak.
There are plenty of outdoor rated 120 volt or 220 volt AC down to 12 or 24 volt DC transformers on the market. They are generally for landscape lighting.
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I suppose you could operate the ball valve from a relay controlled by the arduino. Then your alarm condition could read something like
if(ballValveRelay == OFF && pressureSensor < threshold){
sound alarm;
}
This way it might know better if the pressure drop is due to the irrigation or not.
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I use one of these valves. Easy to operate, low current, 2 wire operation.
Can be operated on a 9V PP3 battery. -
Your issue will be in measuring meaningful water pressure.
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Water at 5AM when the pressure should be constant and adjust the valve to open based on your requirements.
Calibrate motor ON time thru experimentation. My valve fully opens/closes in only 4 seconds. -
Design your circuit to have a manual fallback option.
Why? The pressure does not depend on the pipe size.
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Because I want to monitor the pressure drop on the house side, when it drops below a certain pressure the assumption is that the irrigation is on as well, which means, close the valve to the irrigation to divert more water to the house. The lines I am working with are 3/4", I will most likely reduce the 3/4" down to 1/4" or similar to accommodate the pressure transducer via a tee with a bushing.
- Is the main line 1â ?
That's actually the same brand I just ordered but the 5 wire. I have a feeling I will be getting a little carried away with the logic on when it can turn on and how it will respond to the pressure changes.
I have one of these coming McMaster-Carr to be used as the pressure transducer. Looks like I'll need a few extra components so the Pi5 can use the signal.
When you say manual fallback option are you referring to a bypass or isolation.
Negative. 3/4". I wish I had 1" main.
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If you plan on controlling the valve with a controller, itâs nice to have a way to switch between Auto and Manual operation.
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BTW, my valve works on voltage polarity, hence only 2 wires.
A simple DPDT relay with a ON/OFF relay is how I control the valve.
So, you have a relay to turn the power on/off to the switch, then the DPDT to open/close the valve.
I was thinking a 3 position switch could do the same? toggle left - close, toggle right - open, toggle middle - no change. Would the relay be necessary or was that just a nice to have.
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Relays allow a controller or electronic circuit to take control of the valve.
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One of my valves is connected to a water monitoring/leak_detection circuit.
You can see the Auto/Manual switch in the design below.
K1 is a DPDT relay
Terry, the connection between the water main and the irrigation ALSO needs a check valve!
Not my schematic, it's the OP's from post #1!
Ah, then when the water company discovers there is nothing stopping the irrigation water from flowing back into the water mains, he will learn about such things!