low power water solenoid valve

Why reverse engineer it? You were looking for a valve, and it's a valve.

Here is another one:

Another option may be to replace the solenoid of a regular valve with a DC "latching" version:

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Regards, Joerg

http://www.analogconsultants.com/

I totally agree. However I'm new to electronics and a software engineer by trade. I had someone helping me trying to figure out how this valve works. I used a variable power supply to apply power thinking I could get the valve to open with no luck. After some help from a group that does this sort of thing it was determined it had a pilot valve that works with water pressure. I assumed this was the reason it wasn't working. I then hooked it up to a hose and tried applying power again with no luck.

Not followed this thread. But I assume that you don't understand how these simple water valves work!

The pressure of the water supply is used to both open and close the valve. All the solenoid plunger does is to open and close a tiny bleed hole. It is important that the water supply is filtered, since even a very tiny particle can stop the valve working compleatly. A filter is normally included in the inlet entrance.

As far as the voltage required is concerned, that will depend upon the coil, ie ac or dc and the force required to lift the plunger against the return spring. There is little physical difference between a 12v DC supplied valve and a 240V AC supplied one other than a shading ring.

HTH.

--
Best Regards:
                     Baron.

There needs to be water pressure and it has to be in the usual utility service range. Also, you normally have to apply the power in "digital" fashion, gradually increasing the voltage from a lab bench supply may not work.

The usual diaphragm valves won't open when there is not enough pressure or not enough water flow during the opening phase. If that presents a show-stopper problem for your project you might want to check the off-grid market where people have to water from cisterns and with low power solar. That's going to cost though.

--
Regards, Joerg

http://www.analogconsultants.com/

Hi Baron, No I don't know anything about how these valves work, I'm trying to learn :) I did notice that small bleed hole and wondered what its function was.

Yes the inlet portion has a filter built in.

I have a unit from orbit that looks like it has the same valve you see above. It runs on 3 AA batteries.

There is where I'm missing things. I was working with some people that do microcontroller work and integration of hardware like this. I was relying on their expertise but they sort of disappeared and didn't really understand what I was up to. They told me I could try just applying power with it hooked up to a water supply.

How do I apply power in a digital fashion? Is this something that can only be accomplished by integrating with my microcontroller?

This shouldn't be a problem my garden hose has enough pressure to open the current orbit device I have just fine.

I do understand I'm in over my head here but I'm *really* enjoying learning and well why not ... baptism by fire :) I've wanted to do something with microcontrollers for a long time and I purchased one of these kits from Freescale:

I understand I have several problems. 1) understanding how these valve works and how they are powered, 2) building a circuit that can then be integrated with the microcontroller to power the valve to open/ close.

I need some good books to help me learn ... any suggestions?

Mark

If there was no water pressure, how did you expect to tell if the valve was open or closed?

Thanks, Rich

Don't worry - that only means on/off. :-)

Cheers! Rich

Its function is to equalise the pressure on both sides of the diaphragm.

Examine the disassembled valve very closely and you will see that the water pressure bleeds through the small hole and applies force to keep the valve closed. Lifting the plunger opens the centre hole allowing the pressure to exit. The water pressure from the other side now pushes the diaphragm away and water flows out.

Really very simple and ingenious in concept. Since almost no effort is needed to stop hundreds of psi. In fact more pressure closes the valve more tightly. Some air valves work is a similar fashion.

I would have expected it to have one, particularly if it were for hot water!

Yes! As long as the plunger can be lifted a small amount then it will function properly.

Very often there is also a restrictor washer fitted which has to be removed for low pressure/flow rates.

I think what Joerg means here is either apply the rated voltage, on or off. Simply applying a slowly rising voltage will not control the rate of flow of the water through the valve.

In fact I don't think applying a square wave at the rated voltage faster than, say 1 cycle per second will allow any more than rudimentary control of the flow through the valve. This is because the valve is a very slow device in practice.

You can turn on the valve for say several seconds, then turn it off. But that is about all you will achieve with this kind of device.

See above par..

Yes I agree. A gate valve would be a better bet for flow control!

Probably not the best for this application.

I hope that I have helped you understand how and why this kind of valve works the way it does. In short it is an on or off type of device with no in between's. It does not lend itself to digital control in the way I belive you want to use it.

--
Best Regards:
                     Baron.

[...]

If power consumption is a concern there is a trick: Use full current only for a split second, then reduce to whatever holds the solenoid up with enough margin. Can be done with a capacitor. With a uC it's much easier because you can use two port pins to control the current stage. Both on for opening, then set one of them low.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

haha .. I thought something a bit more complicated was being said :)

The valve makes a distinctive *click* when it's opened or closed. It's actually quite loud.

I took pictures previously to describe it to someone else:

I chose the freescale device because I'm trying to build a wireless watering device. Something I can control remotely and program to have a schedule or even to tell me when it's watered, etc.

I can't think of why I would need more than simple on and off. You have helped greatly thanks. However I'm still baffled as to why applying the rated voltage (part of the problem, I don't know this) didn't open the valve. I wasn't slowly ramping the voltage, I put the power supply at 3 (then 4 I believe) volts with 1 amp and touching the wires to what I believe were the correct contacts. The ohmed values I got were:

Black to Red - 3.6 Red to Orange - 3.9 Black to Red - 0.5

Mark

Yes I saw your pictures. However I don't understand the three wires! Only two should be needed. Since its all plastic and low voltage I don't think it would need to be earthed.

The freescale will give you that ability.

I'm sorry but it isn't clear to me, is this a low voltage coil and is it DC ? If so then unless the coil is faulty the valve should open. You say that you can hear an audible click which would be normal, but water doesn't pass through.

Unfortunately these don't make sense! Please recheck! you quote "Black to Red" twice.

--
Best Regards:
                     Baron.

I was told Black to Red was a path to open the valve and Red to Orange was the path to close (or vice versa).

This plugs into a device which uses batteries. I will find a link to the device and re-post.

Sorry I meant:

Black to Orange - 3.6 Red to Orange - 3.9 Black to red - 0.5

Please! I haven't seen your device.

Ok. How many wires are actually connected to the coil ? Two or three. Normally there would only be two, since the spring will return the plunger to the off position.

The only concept that I think of that would use three wires would be where the valve is held open by an embedded magnet and requires a reverse polarity to close it.

I have seen these in both two and three wire systems. In the first the supply polarity is simply reversed and in the latter a common terminal with two coils wound on a common core. These cost more to make. I don't think such a low cost device would use this scheme.

The advantage of course would be zero power consumption to hold the valve open. Using batteries this would be a big advantage.

--
Best Regards:
                     Baron.

Here is a link on amazon that shows the battery powered device that controls these valves

Look at this photo:

It shows 3 wires going to the coil. The black has 2 wires twisted together going to the coil and then there is one from the red and one from the orange. I would have to break into that hardened plastic to see the way they're actually connected to the coil internally.

Mark

Right! This looks a bit like the kit that "Aldi Stores" sell for £15.

Yes it looks like the coil has two windings. The black being the common one.

No need to! You have obviously taken the valve apart. With the coil detached and the plunger inserted with its spring. Applying the battery voltage (4.5v or what ever it should be) between the black and one of the other two. Does the plunger pull in and stick after the voltage has been removed ? Or does the spring push it back out ?

What happens if you do the same with the other wire ?

--
Best Regards:
                     Baron.

Use 3 1.5 volt _new_ batteries in series to give you

4.5 volts to operate the solenoid. Your supply may not be able to provide the current needed.

Ed

dr fence snipped-for-privacy@gmail.com posted to sci.electronics.design:

I don't suppose that you can figure out the make and model? With that you can google up the vendor and perhaps a datasheet.

dr fence snipped-for-privacy@gmail.com posted to sci.electronics.design:

What i can see from the photos black is common, and red and orange will open or close the valve. I will bet that it is bistable, needing current for only a second or two. I will further guess that

5V at 50 MA is sufficient to operate the valve. Such valves are actually quite common in remote controlled irrigation systems. (though they are usually built to be solvent welded to PVC pipe.