Servo or dc motor for water valve?

Hello - I’m planning an arduino controlled watering system. Currently i use 2" valve as seen in the attached picture. I would like to connect a servo or motor to it to open and close. Could anyone help point me in the right direction ? Would i be best to use a servo , or a dc motor and driver. The valves are somewhat stiff so would require a bit of torque. Any suggestions for hardware? And also which library would i need to learn to control it. Thank you!

Perhaps the first thing is to try to quantify "a bit of torque". Maybe rig some kind of lever and hang some weights on it?

Or, change tack and look at a solenoid valve?

Thanks. And my apologies for not being specific about the amount of torque. I would have to figure that out.
The solinoid valve might be a good idea. I hadnt thought of them so I googled it. Any idea how they work? Do they just have a positive, negative and signal wire typically?

Any idea how they work? Do they just have a positive, negative and signal wire typically?

I've never used one so not sure tbh. They might even just have power wires so you have to manage that through a relay or similar. If they do come with a signal line then I imagine that would be a logic level high/low to control it.

One thing I do know is, some types require decent fluid pressure to open the valve. The solenoid just "unlocks" it a and the water opens it. So bear that in mind.

But that would save you a heap of trouble trying to Heath Robinson a motor onto that valve you have.

Thank you manor_royal. I think you're right. Seems much easier to go with a solenoid valve. Thanks for the advice!

katana_flyer:
Thanks. And my apologies for not being specific about the amount of torque. I would have to figure that out.
The solinoid valve might be a good idea. I hadnt thought of them so I googled it. Any idea how they work? Do they just have a positive, negative and signal wire typically?

First, torque on the ball valve is quite variable because they have a rubber seal around the ball and it gets stiff with age and lack of use. I have even broken the handle on a few.

Second, a 2 inch solenoid valve is quite expensive, even used. The lowest priced one on Ebay is currently $119. I have only seen ones that operate on 120 volts AC.

Your irrigation system, like mine, is probably a low pressure system. My system fills a 1,000 gallon tank from the domestic well. The connection to the well is 2 inch PVC pipe and has a 120 volt solenoid valve to fill the tank. The type of valve is called a "piloted" valve in that the solenoid only opens a tiny port to the pressure side of the valve, which then lets the pressure move the diaphram controlling the main water path.

A second piloted solenoid valve allows water from the tank to go to the pump input. When the pump shuts off, the valve closes to stop water from draining out of the tank and through the now stopped pump.

I kept watch on Ebay for about two years looking for suitable solenoid valves. I think they were excess devices from municipal water systems. There was little bidding for the big valves, so the price was reasonable. You may be able to do the same.

Paul

Ive been using these types of valves on my watering system for over 4 years now.
https://www.aliexpress.com/item/New-12V-Electric-Solenoid-Valve-Magnetic-DC-N-C-Water-Air-Inlet-Flow-Switch-1-2/32699483604.html?spm=2114.30010308.3.21.o5c2TT&ws_ab_test=searchweb0_0,searchweb201602_0_10065_10068_10000009_10084_10083_10080_10082_10081_10060_10062_10056_10055_503_10054_10059_10099_10078_501_10079_426_10103_10073_10102_10096_10052_10050_10107_10051_10106,searchweb201603_0,afswitch_5_afChannel&btsid=bddc9311-6d62-4e81-bb2c-562c9bbacff7

They are a mains pressure valve, so need 40psi + to open.
They draw around 250 ma at 12V .
The valves feed water into a pressure reducer to feed the sprayers.
Make sure to connect a diode across the coil to stop voltage spikes when the valve turns off.

Paul_KD7HB:
First, torque on the ball valve is quite variable because they have a rubber seal around the ball and it gets stiff with age and lack of use. I have even broken the handle on a few.

Second, a 2 inch solenoid valve is quite expensive, even used. The lowest priced one on Ebay is currently $119. I have only seen ones that operate on 120 volts AC.

Your irrigation system, like mine, is probably a low pressure system. My system fills a 1,000 gallon tank from the domestic well. The connection to the well is 2 inch PVC pipe and has a 120 volt solenoid valve to fill the tank. The type of valve is called a "piloted" valve in that the solenoid only opens a tiny port to the pressure side of the valve, which then lets the pressure move the diaphram controlling the main water path.

Thanks Paul, my irrigation system is actually high pressure. I'm pumping water with a pressure pump and sending it nearly 500 feet through a 2" header pipe branching off to 1.5" lines to field sprinklers.
Since my last post, I found some valves online that work off 24VAC, they are similar to what you say in that the pressure is what maintains the diaphram in the open position. I guess I will just need to use a 24V power supply and a relay between the 5v from the arduino and the AC... but yes, I'm gonna pay for them alright!

Do you have any experience using water pressure transducers that could be connected to a watering system, and rigged up through the arduino ?
Thank you....

mauried:
Ive been using these types of valves on my watering system for over 4 years now.
https://www.aliexpress.com/item/New-12V-Electric-Solenoid-Valve-Magnetic-DC-N-C-Water-Air-Inlet-Flow-Switch-1-2/32699483604.html?spm=2114.30010308.3.21.o5c2TT&ws_ab_test=searchweb0_0,searchweb201602_0_10065_10068_10000009_10084_10083_10080_10082_10081_10060_10062_10056_10055_503_10054_10059_10099_10078_501_10079_426_10103_10073_10102_10096_10052_10050_10107_10051_10106,searchweb201603_0,afswitch_5_afChannel&btsid=bddc9311-6d62-4e81-bb2c-562c9bbacff7

They are a mains pressure valve, so need 40psi + to open.
They draw around 250 ma at 12V .
The valves feed water into a pressure reducer to feed the sprayers.
Make sure to connect a diode across the coil to stop voltage spikes when the valve turns off.

Thank you Mauried,
I had a look at the link. The valve is too small but they may also have on there what I need.
Would you mind to explain a bit more about using the diode? Would I need this no matter what solenoid valve I decide to go with?
Thank you.

katana_flyer:
Thanks Paul, my irrigation system is actually high pressure. I'm pumping water with a pressure pump and sending it nearly 500 feet through a 2" header pipe branching off to 1.5" lines to field sprinklers.
Since my last post, I found some valves online that work off 24VAC, they are similar to what you say in that the pressure is what maintains the diaphram in the open position. I guess I will just need to use a 24V power supply and a relay between the 5v from the arduino and the AC... but yes, I'm gonna pay for them alright!

Do you have any experience using water pressure transducers that could be connected to a watering system, and rigged up through the arduino ?
Thank you....

You might get one and try it on DC, if you have a variable voltage supply. AC relays and solenoids will all operate off much lower DC voltage. DC makes continuous magnetism when AC is going to zero and reversing continuously. Try 6-9 volts. You will be operating the valves on a continuous basis, so heating will be your determining factor.

My pressure transducer is a pressure switch on the pump output. Operate by hand until the water pressure takes over. Loss of pressure or power failure turns the whole system off.

Paul

Paul_KD7HB:
You might get one and try it on DC, if you have a variable voltage supply. AC relays and solenoids will all operate off much lower DC voltage. DC makes continuous magnetism when AC is going to zero and reversing continuously. Try 6-9 volts. You will be operating the valves on a continuous basis, so heating will be your determining factor.

My pressure transducer is a pressure switch on the pump output. Operate by hand until the water pressure takes over. Loss of pressure or power failure turns the whole system off.

Paul

Thank you Paul, great to know about using a lower DC voltage. When you say heating, do yo mean by a steady current? I was under the impression that the voltage "unlocks" the valve and the water pressure keeps it open. Then only requires voltage to "lock" it again. Am I wrong in this thinking? Thank you.
Also; I think I chose the wrong term for pressure transducer, I meant a sensor to send a voltages to the arduino to calculate water pressure in the pipe.... Thank you.
Morgan...
Ontario, Canada

also; the more I read the more I see that what I thought was wrong. Seems as though they require a steady supply of power in order to keep valve open. Once power is turned off, the valve closes. Is this correct? The piloted part just means it doesn't need to pull up the whole valve, the pressure does this but the power is still required to allow that diaphragm to open by the pressure of the water....
If so, is it the same voltage the whole time, what I mean is if I apply 24VAC for example to open valve initially, would I just keep the same 24 VAC applied to maintain an open valve state or should it be reduced?
Thank you.

katana_flyer:
also; the more I read the more I see that what I thought was wrong. Seems as though they require a steady supply of power in order to keep valve open. Once power is turned off, the valve closes. Is this correct? The piloted part just means it doesn't need to pull up the whole valve, the pressure does this but the power is still required to allow that diaphragm to open by the pressure of the water....
If so, is it the same voltage the whole time, what I mean is if I apply 24VAC for example to open valve initially, would I just keep the same 24 VAC applied to maintain an open valve state or should it be reduced?
Thank you.

The valve needs the stay activated to stay open. Same voltage throughout the whole open time. A spring in the valve will push the diaphragm closed as soon as the pilot path is closed.

Paul

Thanks Paul, I’m on my way to getting this thing together! Did you happen to see my bit about using the wrong term for the transducer, what I meant was a water pressure sensor… any idea what option would be best or what exactly I should be looking for in order for it to work with the analogue in pin on the arduino…

katana_flyer:
Thanks Paul, I'm on my way to getting this thing together! Did you happen to see my bit about using the wrong term for the transducer, what I meant was a water pressure sensor... any idea what option would be best or what exactly I should be looking for in order for it to work with the analogue in pin on the arduino...

Not an electronic one. I use a manual gate valve to allow water to bypass the irrigation output of the pump and go back into the tank until a pressure gauge shows the pressure I need. My sprinklers won't work right if the pressure is too high. I have several irrigation lines that have different number of sprinkler heads.

Paul