system design

[kenvogt]

I would like to create a watering system that has control over both zone timing and zone volume. Can anyone suggest how I could use OpenSprinkler to achieve the following:

Zone 1: every three days; 7:00am – 7:15am; 40 gpm
Zone 2: every three days; 7:15am – 7:30am; 10 gpm

In other words, I want to control the frequency, the duration, and the volume. It’s the volume part I am not clear about with OpenSprinkler. I would like to make volume at least roughly controlled programmatically rather than just physically. We can assume the water pressure remains basically constant.

[EH]

The “low-tech” method that is not software controllable is to put a flow restrictor on each zone that will give the flow level you want. You can use fixed flow adapters or a manual ball valve that you adjust to get the flow you want.

Programmatic control of flow would require a flow meter in the line hooked up to one of the sensor connections, and use of an electrically controlled variable flow valve. Electric variable flow valves are typically only used in industrial settings and are consequently quite expensive (around $500 or more). I’m pretty sure that the software doesn’t yet support control of a variable flow valve, but it should be possible if you can find a suitable valve.

I actually found the opensprinkler project because I was doing research trying to build my own system that had software control of both pressure and flow. At the moment I’m trying to dig far enough into the hardware and software designs to figure out if OS can be adapted to do what I want easier than building my own system.

[IDtheTarget]

I’m actually looking for the ability to modify the flow rate as well. That’s why I’m drawn to the OpenSprinkler project, I need to be able to have two programmable flow rates. (I’m not looking to use the system for gardening, but for bird water bowls. I need a high-pressure to clean out the bowl, and a low pressure to refill the bowl.

EH, I think you may be wrong about the cost. I found this on Amazon, and it’ basically what I’m wanting to control (though I’m not fixed on this particular model or brand):
205T-FC 1″ with Adjustable Flow Control

[Mike]

@IDtheTarget
That looks like a manual flow control valve, not a programatically controlled one.

[kenvogt]

I agree with Mike that that one looks like it is manually controlled. But we don’t need a “smart” valve, we just need one that is electronically controllable (which shouldn’t cost $500), the valve itself doesn’t need to be programmable.

[IDtheTarget]

Yep, you guys are correct, dangit.

[EH]

I’ve done a ton of research trying to find electrically flow controlled valves, and it took a long time for me to find an option that wasn’t in the $250 and up range, with almost all being in the $500 and up and “industrial” grade.

BUT, my work seems to have paid off. The best option I have found so far are valves like these: https://www.amazon.com/dp/B0119ZI38U?th=1
I haven’t purchased one yet, but I think these should be able to be controlled using PWM to slow down the actuation speed to get more control of the position, and coupled with a flow sensor gives the feedback necessary to adjust it well, and even makes it possible to adjust for changes in pressure. Unfortunately I can’t find ones that are reasonably priced that work with 24VAC like regular sprinkler valves, so they will require a separate power supply or a voltage converter.

[RottenMutt]

You could use two sprinkler valves per bowl, one to flow unrestricted to flush, and the the second with a restricter to fill.

[Ray]

You said 40 gpm, which I assume means flow rate (i.e. gallons per minute), not the total volume. How does one control the flow rate? Isn’t that fixed by your water source? Or did you mean to control the total volume, within, say, 30 minutes of water time? Still, I am confused how you can control both the water time and total volume at the same time — what if with your water source’s flow rate, the water time and total volume do not agree with what you want them to be set?

[EH]

In my previous post I gave a link to a low cost motorized ball valve from Amazon that looks like it could be used as an adjustable valve. All that is needed then is a flow rate sensor to drive the valve motor (probably with PWM to slow down the adjustment) until you get the flow rate you want. Lots of relatively low cost flow rate sensors seem to be readily available, and would only use one of the sensor pins.

[Ray]

Sorry, I must have missed that link when I read your post the first time. I didn’t know these valves exist. Do you know how to control the flow rate — in other words, what’s the electric interface to set the flow rate on these valves? OpenSprinkler can only open or close a valve, I am actually curious how to tell those valves to, say, open 50%, and if that’s the way to open it, how to close it afterwards. It sounds like this would require reversing the voltage polarity which is something that OpenSprinkler can’t do yet (the OpenSprinkler Bee can do so).

[Author]

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