Looking for a valve for use with Arduino

You don’t have to use AC it will work on DC we used it with 12 volt DC to make a water cannon.
http://www.homedepot.com/p/Rain-Bird-3-4-in-FPT-In-Line-Valve-CP075/202078357

dwightthinker:
http://www.rainbird.com/LANDSCAPE/PRODUCTS/valves/PESB-Rseries.htm
Dwight

$112+ and 1" plus. I think they are a little oversized and overpriced.

be80be: You don't have to use AC it will work on DC we used it with 12 volt DC to make a water cannon. http://www.homedepot.com/p/Rain-Bird-3-4-in-FPT-In-Line-Valve-CP075/202078357

I haven't seen anything like that in stores near me. Likely because none of them stock it according to the websites, Lowe's and Home Depot. Ports are a little large but I think I can work with it, the price is right.

adwsystems the one I posted in 8# is a baby of post 20# post 20 it's $14 post 6 it's $6 And yes the valve in post 20 is big Post 6 is a baby but there both push pull types. I played with the big one nice water cannon for school. The little one could make a nice water wall. They have them here there green and just a little smaller.

You do realize that these need a minimum pressure to close. They use the water pressure it self to close the valve. The solenoid only operates a tiny needle valve. The battery operated hose controls use a small DC motor and a threaded linear actuator to open and close the needle valve. That way, the only need current when changing states. Here is a good article on these valves: http://rayshobby.net/understanding-24vac-sprinkler-valves/ It seems you need to hit them harder to actuate them. This can be done with a 12V and a 5V DC source. We have an arduino with two PFets in the source, one a 12V and the other a 5V ( with a blocking diode ). You need two outputs. One does need a buffer transistor and resistor to get the 12 swing but the 5V PFet can be driven directly. (assuming logic level Fets ). It is now just a timing thing with milliSeconds() Dwight

dwightthinker: The solenoid only operates a tiny needle valve. The battery operated hose controls use a small DC motor and a threaded linear actuator to open and close the needle valve. That way, the only need current when changing states.

Any idea if these can be gotten in US for little money?

dwightthinker: You do realize that these need a minimum pressure to close. They use the water pressure it self to close the valve. The solenoid only operates a tiny needle valve.

Here is a good article on these valves: http://rayshobby.net/understanding-24vac-sprinkler-valves/ It seems you need to hit them harder to actuate them. This can be done with a 12V and a 5V DC source. We have an arduino with two PFets in the source, one a 12V and the other a 5V ( with a blocking diode ). You need two outputs. One does need a buffer transistor and resistor to get the 12 swing but the 5V PFet can be driven directly. (assuming logic level Fets ). It is now just a timing thing with milliSeconds() Dwight

I assume by the 12V and 5V PFets, you are referring to the two-stage circuit to open and hold the 24VAC valves?

What about back pressure (or negative differential pressure, outlet higher than inlet)? Does any one know if the 24VAC irrigation valves will open in a negative differential pressure situation? (and I do expect that to be a possibility)

The unit I suggested was just an example. I don't know of any motor driven valves outside of the built in units. That would be a little to expensive. You'll have to look for ones that are self holding.

As for back flow, any of them will back flow if the pressure is greater on the outlet than the inlet. This type of problem is solved with a check valve.

And yes, using the two FETs is to overcome the problem of using a DC source when one wants to hold with a lower voltage for power dissipation problems in the coil. This allows the coil to pull in and then change to just a holding current. This is described as an issue in the article I pointed to. Dwight