I'm trying to build a plant watering system with a lot of different places that could be watered or not watered. I've been looking at solenoid valves online and haven't found much of anything that seems cost effective for watering many different spots that may or may not need water at different times.
I don't need high flow rates, in fact, a very low flow rate would be preferable.
Does anyone know where I can get controllable water valves (probably a solenoid valve) for inexpensive, maybe around $5 each? The closest thing I found were some fountain water pumps for $3 each sold in a lot of 42. But I figure pumps would be more prone to breakage.
I just realized that the washing machine valves have two inputs (for hot and cold water, I assume), but one output. I wonder if I can reverse the flow of water through them, or if that reverse pressure will cause the valve not to work?
You don't say whether this is an indoor or outdoor setup; if it is for outdoor, then your best bet (if you can set it up) would be sprinkler valves for the plant zones, and control those.
But I have a feeling you are wanting to do this for indoor plant; call it a hunch.
You might actually try rigging small brass ball valves for 1/4 inch line to servos; I have such a valve set up for manual control of some outdoor misters in an infrequently used area, and they work pretty well. You could mount the valves to a piece of plywood or polypropylene (plastic cutting board), along with the servos, connecting them with a linkage to turn the valve on and off. Use a custom manifold to connect the water supply, then standard 1/4 drip irrigation tubing from each valve to the plants. At that point, you write code on the Arduino to control the servos.
Yeah, I was designing for an indoor setup. An herb garden for my kitchen to be specific. The problem is, I don't want to water my rosemary that grows slower and likes to dry out before being watered again just because my fast growing peppermint sucked up all the water in its pot. I was hoping to water each of maybe 7-10 plants separately. But all the solenoid valves I could find are $15-$30 which is a little cost prohibitive, especially if I want to do some other stuff as well.
How much are the valves that you were using, were you able to get a better price?
I just had a singular valve; it was a standard brass valve I purchased at Home Depot or Lowes, probably only cost $2-5.00 US each. You can probably also find plastic ones that might be a bit cheaper. The hard part would be getting a servo with enough torque to turn the handle; you would need a good linkage, and maybe if you extended the handle of the valve a bit (solder on some brass rod or something), you could get more leverage so the servo could turn it (you don't want to use expensive servos, because that would defeat the purpose, of course). If you go this route, make sure once you have things debugged and somewhat working that you make all connections leak-free, then place the entire thing in a plastic container and set it up such that leaks won't cause issues. You might also want some method to perform a "main shutoff" if something fails (unless you want a mess).
What about fashioning a cheap 'pinch' valve using a motor, or servo?
I'd think you want to look at cheap roll/pinch closures ala medical drip devices???
What about fashioning a cheap 'pinch' valve using a motor, or servo?
I'd think you want to look at cheap roll/pinch closures ala medical drip devices???
THAT'S ASKING for a visit from the INSURANCE GUY, when the setup fails
The point of automatic watering system, is that you can count on the system working 24/365, without supervision (well, almost)
I think a pinch valve is a good idea. You might even be able to build one yourself with plastic tubing, a disk with an eccentric hole, and a solenoid.
Or how about this: http://www.aquariumguys.com/4plva.html. A spring and a small solenoid might be able to open and close these. It would probably leak a little, so what?
On the other hand, a real sprinkler valve can be had for $12.
The annoying part about them is that it's a full size pipe, so you need to have all the plastic bits to get it up and down to small diameter tubing that you really want for this.
it's a full size pipe, so you need to have all the plastic bits to get it up and down to small diameter tubing
Drip irrigation tubing is probably too stiff for a "crimp valve", but the fittings and adapters should work with something softer, and be available cheap.
On the other hand, a real sprinkler valve can be had for $12.
Sprinkler valves require pressure behind them to operate properly; the OP didn't say whether they were going to use standard water pressure, or a separate low-volume pump system.
If they were going to tee into the regular water pressure (they said it was for a kitchen herb garden - so, maybe under the sink?), then if they have the room, going with standard sprinkler parts and electric valves, manifolds, etc - to drip irrigation parts - would probably be the best bet (just be sure to glue EVERYTHING together, sprinkler valves have a habit of coming apart when you least expect them to - and generally when you are away from home - not that big of a deal if its outside - just a large bill - but inside - eegh).
Drip irrigation tubing is probably too stiff for a "crimp valve", but the fittings and adapters should work with something softer, and be available cheap.
1/4 inch silicone aquarium air-hose tubing is very flexible, and will work with drip irrigation parts just fine.
I was debating about weather to use a reservoir and then have a gravity fed system, or just tap into the house water supply. I know some valves only work with one or the other.
Sounds like the sprinkler valve might be the cheapest so far after accounting for extra parts and time to implement the other solutions?
Doesn't it seem that a solenoid valve should be available somewhere on the cheap though? From what I understand, its not a terribly complicated part and used for a lot of applications. I feel like I'm just looking in all the wrong places...
Only lists air service, however does rate pressure range as 30 to 105 psig.
Another spec important to valves (manual or solenoid) is it's CV (flow capacity) rating. That it's volume of media passed at a specific pressure drop. It has to do with the actual orifice size, smaller passage of course passes less material at a given pressure then a larger passage. Of course large orifices converts to larger parts, stronger magnetic force, etc, so larger size and larger costs for more flow capacity.
Thats too bad it only has air service, that would have been a nice one. Though it would be better if I could find something new that way I would have a consistent source of parts that I was familiar with and would interface with my current infrastructure.
I'd actually prefer something smaller and with a low flow rate. It really only has to water the plants faster than water evaporates which is setting the bar pretty low. Anything with a high flow rate, I'd have to cut down anyway to make sure I was watering slow enough so that the water was permeating through the soil to the moisture sensors and giving me time to adjust.
Sprinkler valves work fine at drip irrigation pressures. Using drippers for this application is probably just what you want. That means you come off of a faucet, through a drip irrigation filter and pressure reducer, through a manifold to the sprinkler valves, down to small diameter tubing and off to drippers in the herb pots.
gotta agree, if you are using the city water mains to feed the system. Anything less leaves you liable for a flood.
Of course you could always use a sprinkler valve for a master valve and make pinch valves for all the seperate plants, add it into the code that if all valves are to be closed, it would close the master first and have a short delay to release any pressure before closing the pinch valves.
A simple pinch valve could be made fairly easily, take some small flexible tubing, and have a small strip of plastic or metal against the tube. Then have a servo next to it with a pin on the end of an arm. When the valve is to be closed, the pin on the servo would push the tube down around the strip to kink the hose shut.
Another place to look could be the valves for refrigerator ice makers. They typically use 1/4" tubing and would be perfect for plant watering. I'm not sure if they're switched by 110v or mechanically, but with some thought you could probably add or replace a solenoid or just control it with a relay.
