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[on:]

I'm new here, and one of the projects I'm thinking about is a system to water potted plants. I haven't ordered any parts yet.

I was thinking about putting a soil probe in the flowerpot and having an elevated cistern. The soil probe would tell a board when that pot needed to be watered, then the board would open a valve at the bottom of the cistern, and a flow meter would report back the flow rate so that the board could shut the valve when a certain amount of water had passed through. Probably not the most efficient way of getting the job done, but I would be able to apply some concepts to another project I have in mind.

If that sounds good, I was hoping I could get some opinions/advice about some hardware I was looking at.

I think I've seen posts where people have talked about using this:
http://www.seeedstudio.com/depot/water-flow-sensor-p-635.html?cPath=6&zenid=594b89701c7a2015a13064b67aed4f44
so far I'm not worried about this peripheral not working with a board (the attitude may change if I try this out), the only worry I have with that now is the flow rate wont be high enough to register.

What I'm not seeing is people talking about is this:
http://www.seeedstudio.com/depot/electric-solenoid-valve-p-636.html
It looks like it could be used in this application, I like it because it is inexpensive, but I don't see examples of it being used with arduino boards. Did I abandon my search too soon, or not look very hard? Can any give or cite examples of this being used with arduino boards? Perhaps there is something else out there like this that would be a better fit for this type of project?

[Reply #1 on:]

Both of those should work just fine with Arduino.  See this http://arduino.cc/playground/Learning/SolenoidTutorial for information on using the solenoid with Arduino.

Look here http://www.seeedstudio.com/wiki/index.php?title=G1/2_Water_Flow_sensor#Reading_Water_Flow_rate_with_Water_Flow_Sensor for information on using the hall effect water flow sensor with Arduino.

[Reply #2 on:]

Electrically that valve will work, however one problem with most solenoid valves is that they need pressure to crack, a simple gravity feed from a header tank won't cut it.

That one may be different but bear that in mind.

______
Rob

[Reply #3 on:]

it lists pressure as "0.02~0.8MPa", I assumed that meant pressure wouldn't be an issue, was that a bad assumption?

[Reply #4 on:]

Hmm, I really don't know. That's about 3-116psi and it may refer to the min pressure required to hold it open (3) and the max it can handle (116).

Whether or not the pressure needed to crack it is somewhere between these values I don't know. I have been caught with this before though when using a different type of solenoid valve.

______
Rob

[Reply #5 on:]

just a question: that fritzing image isn't correct, is it? the ground is not connected and the signal is connected to the Vcc, which is rather strange..
i think they misundertood the lay-out of the breadboard xs

[Reply #6 on:]

I'm looking at relays for this project, both of those devices require 24V I think. would this work:
http://www.seeedstudio.com/depot/relay-shield-p-693.html?cPath=132_134
How might it limit the pins I have available?

The board I'm currently using is an Arduino Mega.

[Reply #7 on:]

What about a windscreen washer pump and reservoir? http://www.amazon.com/ACI-99300-Windshield-Washer-Pump/dp/B00495UQT2/ref=sr_1_5?s=automotive&ie=UTF8&qid=1334699301&sr=1-5. Looks like the kit costs a few dollars more than the solenoid but it includes the reservoir and tubing.

[Reply #8 on:]

... Probably not the most efficient way of getting the job done, but I would be able to apply some concepts to another project I have in mind...

I'm afraid I'm going to be stubborn on the design. The specific parts, though, are up for debate.