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Sprinkler project
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Sprinkler project

by stevenelson on Sun Sep 26, 2010 5:04 pm

I'm working on a sprinkler project and I'm trying to reverse engineer an Orbit sprinkler valve. I've cut the wire sticking out of it and inside are 3 VERY tiny wires. At first they appeared uninsulated, obviously they aren't. But the insulation seems to be painted on. The only way I could get it off was with a soldering iron.

Anyway... I've plugged the wire into the Orbit sprinkler unit and connected a multimeter to each of the 3 wires. I'm getting voltage from two of the wires, but NO milliamps.

I'm a bit baffled. Can this be? Or am doing something wrong?

Steve
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Re: Sprinkler project

by oPossum on Sun Sep 26, 2010 5:51 pm

Sprinkler valves are usually 24 volt solenoids with two wires.

Can you provide a link to the specific valve you have? Or a picture?
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Re: Sprinkler project

by stevenelson on Sun Sep 26, 2010 6:44 pm

I'll take some pictures tonight. One of the wires may be a ground, but it seems strange to have a ground on a device run by 3 AAA batteries.

I just bought a new multimeter this afternoon so I'm not used to it yet. It was showing readings anywhere from hundreds of millivolts to 1.5 volts.

I don't know much about how solenoids work. Is it possible it sends a short pulse to the valve and I just wasn't reading it? Or would is normally send a continuous amount of current while it's open then stop the current when it closes?
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Re: Sprinkler project

by oPossum on Sun Sep 26, 2010 6:56 pm

Oh, it's a timer like this ?

Then three wires would suggest a latching solenoid. The wires would be common, open and close. A pulse on common and open would open the valve. A pulse on common and close would close the valve.
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Re: Sprinkler project

by stevenelson on Sun Sep 26, 2010 7:28 pm

That probably works identical to the one I am using, mine is a slightly different.

Here's the system I'm using:
http://www.amazon.com/Orbit-62032-Yard- ... y_ol_img_b

Here's the stand alone valve:
http://www.amazon.com/Orbit-62035-Extra ... y_ol_img_b

All I have to test it with is a multimeter. If it's sending a pulse of current how do i capture that number? Just trial and error? If the timer is run off of 3 AAA batteries. Why would they increase the voltage to 24volts?

The wires are red, green and copper colors. Any idea off hand which is which?

Sorry for the barrage of questions this is quickly becoming a fascinating project.
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Re: Sprinkler project

by oPossum on Sun Sep 26, 2010 7:46 pm

Valves for underground sprinkler systems usually use 24 volt solenoids. What you have probably uses 4.5 volts (3 x AA @ 1.5 V) to trigger the valve.

Measure the resistance between the wires. That may give some clues about how it is wired.

red to green = ? ohms
copper to red = ? ohms
copper to green = ? ohms
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Re: Sprinkler project

by zener on Sun Sep 26, 2010 9:38 pm

So are we talking latching-water-valve here? That is pretty cool. I have a battery powered hose timer valve but it uses a gear motor for the valve.

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Re: Sprinkler project

by stevenelson on Sun Sep 26, 2010 11:15 pm

Dang it. I'm stuck.

I'm attacking this from two sides now and have failed up to this point. But I'm a lot smarter now.

First of all I've taken this valve almost totally apart now and have a slightly better understanding of how it works. I think you're right that it's a latching solenoid. There is a little pin that feels like it's on a spring, but I suspect that's the feeling of a magnet. I can't take that section apart without breaking it. But I can see a coil of wire in a little hole indicating there is an inductor in there.

I don't have have a triple battery holder. I'll pick one up tomorrow. I've tried activating it with one battery on all 3 pairs of leads, but can't seem to get the valve to move. I have however been able to get resistance levels through the inductor(s).

copper-red: 3.8ohms
green-copper: 3.4 ohms
green-red: 0.3 ohms

Does that tell us anything?

The other way I've been attacking this has been from the timer side. I've ripped apart the adapter that plugs into the timer, soldered on some more stable wires for testing, then tried setting it to "manual" and getting readings. I get voltage readings but they don't change when I turn it on versus off.

copper-red: 0.017v
green-copper: 0.015v
green-red: 0.056v

I don't register any amps and have infinite resistance from the timer regardless of if it's on or off. I'll try more tomorrow. I guess it's possible I'm not working the timer correctly. I'll try in my garden tomorrow with a working valve.

Just to give you an idea of what I'm trying to do...

I'm using an arduino and an ethernet shield to connect my arduino to the net to get the weather forecast. I'll write an algorithm to determine whether it'll rain or not then decide if it should water the grass.
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Re: Sprinkler project

by richms on Mon Sep 27, 2010 12:45 am

The pulses are probably too short for you to measure with a meter.

The wires are more likly to be 2 for the coil, and you reverse the polarity to trigger IMO, the other wire may be for sensing or similar.

The last sprinker timer I had break on me was a geared motor that rotated a ball valve, and had a cam on it to switch the motor off, retrigger the motor and it would go around to the next postion.

The one before that was a latching solonoid but it would do werid stuff like not turn off when the batteries were getting low, so I got rid of it.

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Re: Sprinkler project

by oPossum on Mon Sep 27, 2010 7:20 pm

Those resistance measurements suggest a solenoid or motor on green & copper, and switch on green & red.

Connect a 3 x AA battery pack to green & copper and see what happens.

Post a picture of the guts if you can.
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Re: Sprinkler project

by stevenelson on Mon Sep 27, 2010 8:35 pm

I got it to work! ...Well kind of.

I just grabbed a 3AAA holder from radio shack, popped the batteries in and touched

green-copper: small spark
red-copper: small spark
green-red: tiny spark

Nothing happened except getting tiny sparks. Then I tried holding the metal part of the valve down while touching the green and copper leads like you suggested and viola! It stayed down. Then if I touched the green and red. POP! it popped up. Exactly what I was expecting.

The problem is that I seem to have to hold it down manually. That's no good. Is it possible this thing is broken? I'll take some pictures.
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Re: Sprinkler project

by mitpatterson on Mon Sep 27, 2010 8:50 pm

is it possible it is normally "held down" by the pressure of the water?

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Re: Sprinkler project

by adafruit_support_bill on Tue Sep 28, 2010 5:48 am

This is common for automatic valves. They are designed so that the fluid pressure assists in the actuation of the valve.

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Re: Sprinkler project

by richms on Tue Sep 28, 2010 5:58 am

Yeah, if you turn off the water on the output of them, they will sometimes shut off, which is a pain when using the hose off the timer and kinking the hose to move the sprinkler.

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Re: Sprinkler project

by stevenelson on Tue Sep 28, 2010 5:23 pm

I took a bunch of pictures of this valve. I think I have a pretty firm grasp of how it works. It's raining out now or I'd go hook it up to the faucet and give it a try.

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