# Any info on making a DIY micro-float valve?



## tokyo (Jan 19, 2010)

Ok, so this is for a non-aquaria related project, but I figured the people here might be able to help.

I have 3/8" tubing(like used on water coolers) and I need to make some sort of float valve on the end. I don't have alot of space, so I would like to keep it as small as possible. I also only have vertical room, no horizontal room.

I was thinking of having maybe some sort of tapered plug attached to a wire that would guide it into the end of the tubing as the water level rises. There is not alot of water pressure as the tubing is just gravity fed from a small reservoir(~3liters) a few inches above.

Maybe a cap of some sort would work better than the plug?

Any ideas on how I can make this work?

Oh, and if anyones curious, this is for a compact automatic watering system for a semi-hydro planter.


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## PfunMo (Jul 30, 2009)

Sounds like a fun challenge. Any way you could post up a picure of the setup or a drawing from Paint to show space available? How fail safe does this have to be and are you wanting the water level in the lower tank to stay pretty constant or is it just to change X amount of water daily? We might get some ideas flowing.


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## cgmark (Aug 18, 2010)

I haven't tried it but I have been considering using a water level switch like those used in washing machines. My brother runs an appliance business and I was looking at one of the switches while visiting him. The switch is just small round diaphragm that connects to a long vinyl tube. The tube end is open at the bottom of the washing machines tub. When the machine adds water it raises the air pressure inside the tube and pushes on the diaphragm in the switch causing it to close telling the machine it is full of water.


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## tokyo (Jan 19, 2010)

I think I may just use a float switch hooked up to a solenoid valve. This is the only thing I could come up with that would fit in such a tight space.

I will try to post a drawing when I get a chance. I'm about to head to work, so I don't have time to do it right now.

To give you an idea, it is a flexible plastic planter inside a ceramic planter. The ceramic planter needs to have about 1" of water in it at all times. The plastic planter holds the growing medium(LECA). I then have a 3 liter reservoir that will hold a nutrient/water mix for top offs. The medium still needs to be flushed occassionally to keep it fresh, but the 3 liter container should hold enough water to last about a month.


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## fox (Jun 11, 2009)

The needle valve on a Brigs & Stratton is operated by a float that presses a valve into an orifice as the level rises. Sorta lika a stopper. The needle valve slips into the float so as the level lowers the float drops and pulls the valve open.


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## PfunMo (Jul 30, 2009)

I like electrical things so if room is available for a solenoid, that would be my first thought. The water inlet on a refrig icemaker might be as small and cheap to find as anything salvage. It will most likely have a small(1/4"?) in and out. They use 110 volt making it simple to wire using a set of wires as probes. I have forgotten if the solenoid is held open or closed by the 110. That will need some thought. I like solenoids better than stoppers for controlling flow. The water here is hard and the deposits make stoppers funky to keep working.


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## tokyo (Jan 19, 2010)

Thanks for the suggestions.

I've never used a solenoid valve before. What powers it?

I understand that the float switch sends an electrical current to the valve and that triggers it to open(or close in some cases), but where does the electrical current come from? Do you hook it up to a battery? Can you plug it into the wall? Do you have to hard wire it?

I am not an electrician, will it be difficult for me to set it up? If possible I would like to be able to plug it into a socket, is this possible?


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## PfunMo (Jul 30, 2009)

solenoids are really simple things once you look them over. They are what let the water into washers, dishwashers and icemakers. These are 110 Volt coils of wire that make an electrically operate gate (switch) for the water flow. On your washer it is a double unit for the hot and cold. The water is cut off until the washer timer sends current to the solenoid magnetic coil. This magnet pulls the valve open to let water flow. For your use an icemaker would have near the same inlet/outlet tubing as you have but any would work. Basically need an extension cord, Leave the male plug on, cut the other end off and crimp lugs on to fit the solenoid. When plugged in it will open the water flow. You need a float switch to control when it opens and how long. For that you need a pair of contacts that are tied to a float. When the float goes down the contacts are connected and the water flows.

I'll draw up a plan so that it makes a bit more sense. Solenoids are so handy, I use them for a number of different things.


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## tokyo (Jan 19, 2010)

Thanks

So I need a 110v solenoid to be able to wire it to a plug?

I will be ordering both the solenoid valve and the float switch tomorrow.


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## PfunMo (Jul 30, 2009)

Yes, To plug it directly into the wall you would. If you are ordering and would rather, You might find a solenoid that used a smaller voltage like 9,12 or 24 volt. Then use could use a plug in power supply like a cell phone charger, etc. to power it.










Electricity has to have a full path to work. Think of it as running in a circle, maybe? In this drawing I have a plug at the left. Power comes in on the black line, runs up to the contacts at the tank. When the float(blue) comes down and contacts the two wires, current flows through the red line to the solenoid, through the coil and back to the plug in the wall. This current makes the solenoid open and water flows by gravity down the one tube and up the other to the tank where you want it. When the float go up the circuit is opened and water shuts off. If add a power supply, it just fits between the wall and the plug to drop the voltage down to the safer low voltage. Match the power supply to the solenoid or solenoid to the supply. If you put a timer on instead of the float contacts, you can hook it to a faucet to water flowers while you are gone, etc.


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## PfunMo (Jul 30, 2009)

These are salvage solenoids I've used.


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## tokyo (Jan 19, 2010)

Nice, I like the idea of using a lower voltage solenoid. But how do you hook it up to the power supply? Do you need to take it apart?


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## PfunMo (Jul 30, 2009)

No. What exactly you have to do will depend. Got a cell phone charger that plugs into the wall with a cord running to plug into the phone? That type power supply comes in all kinds of different voltage and power sizes. To use them you will need to get the right type to match the solenoid. I kind of throwing the game into a bit more thinking. The chargers will have a label telling what voltage it puts out. If it is a 12V power supply and you cut the funny little plug off the end and wire it to a 12V solenoid, the solenoid should operate. The hangup is in not only the voltage being right but the amount of electricity (amps) available. Using a cell phone chager is a bad example for me to use. They put out very small amount (amperage or amps) and the solenoid will most likely need much more. When shopping for a power supply and solenoid, you will need to match the voltage of the two. Then there will be a rating for how much power the solenoid needs to operate. The power supply needs to provide MORE than the solenoid needs. The power supply may be a plug in type or it may have screws on it to attach wires. Since we have a very simple circuit, there is no need to worry about polarity ( hot or ground) for this project. Just so the current has a full circle to run round through the item you want to work and back home.


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## PfunMo (Jul 30, 2009)

There's an upgrade I might suggest on the controls. Using home-made contacts with a float will work but if you have some space there, it would be better to replace the contacts with a microswitch. There are small switches with long arms on them that would work well for turning the solenoid on/off. They are not too expensive and they have the advantages of being fully enclosed so that they are safer to use. They also are made for switching power so they would last longer than improvised contacts. Let me know if you are still on board with this and I can tell you what to look for in a switch. Easier to mount and wire as well.


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## tokyo (Jan 19, 2010)

Thanks

I already have a float switch on order from the supplier I'm getting my solenoid valve from.

It's 5/8" wide. Are there smaller ones available? This supplier only had the one style available.

Also, the solenoid valve I'm getting is a 24 volt 10 watt solenoid. Do I need more info to figure out what I need in a power supply?


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## PfunMo (Jul 30, 2009)

No. Those are the two main items. Definitely look for a 24V power supply Then make sure it puts out at least 10 watts or more. more is better there but no reason to go higher than needed. Don't be surprised by power supplies rated in different ways than watts. Might expect to see watts, milliwatts or amps used to rate them. Suggest looking for a conversion table or such if you do. Better for you to look at a table than have me guess! 

Sounds like you may have a handle on it.


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## tokyo (Jan 19, 2010)

PfunMo said:


> No. Those are the two main items.


What other info is needed?


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## PfunMo (Jul 30, 2009)

Make sure the power supply and the solenoid are both either AC or DC. If you do wind up with DC, you will need to make sure the +/- are kept straight but I don't think that will be a question on the solenoid or the microswitch. They normally will not matter as far as correct wiring polarity.

You may find the microswitch has more than two connections. Depending on the type, some have a connection marked "C" for common. One wire goes there. There may also be connections marked "NC" (normally closed) and "NO" (normally open). This just tells you which connection to use if you want the power on or off in the normal unoperated state. In your case if you get water flow when the float is up, reverse this last connection. Lots of switches don't have this and just two connections, but don't let it boggle you if you do find this.

Anybody else notice something I've missed??


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## tokyo (Jan 19, 2010)

Thanks for all the help. This definitely made it alot easier to figure out.

The solenoid is a 24 volt DC and is 10watts.

Any suggestions on what I can look for to use as a power supply? I'm not really sure where to start. Should I just go to the local electronics store and look at cell phone chargers?


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## PfunMo (Jul 30, 2009)

No, cell phone chargers are definitely too small output. That 10 watts is much bigger load. Suggest an internet search for sizing the market and finding what the right price might be. It's late but I will do a little looking tomorrow for possible items. I sold my fishroom overload this weekend so I'm looking for a diversion. :lol:

Thanks to Craigslist, I sold about fifty fish to eager buyers. YEA!


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## tokyo (Jan 19, 2010)

Oh, didn't notice your last response.

Congrats on the sales!

Well, I got the solenoid and float switch a liitle while ago, I've just been waiting for some extra cash to finish up this project. Did you get a chance to look around at power sources? I really have no idea where to start looking? Maybe a laptop charger?

My laptop charger is 19v and 65w, so that wouldn't work, but there may be a 24v charger out there...

Any suggestions would be great

thanks


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## cgmark (Aug 18, 2010)

You really need a transformer based power supply for running solenoids. Most of the wall adapter supplies made now are switching power supplies that do not like being powered without a load attached . Since the solenoid isn't on all the time it could cause those kind of power sources to fail early.

24V adapters are rare but 16V adapters are not. You can tell transformer based supplies because they are heavy and bulky.

Here is a transformer that will do the job.
http://www.allelectronics.com/make-a-st ... ER//1.html

Notice it is a 16.5V AC transformer . That is because AC when converted to DC results in higher DC volts. So 16.5VAC x 1.414 = 23.31 VDC which is plenty enough to power the solenoid. Most solenoids will work in the 20-24V range.

To convert the AC to DC for the solenoid you just need a bridge rectifier
http://www.allelectronics.com/make-a-st ... ER//1.html

Attach the wires from the transformer to the squiggly lines on the rectifier, it doesn't matter which wire goes on which pin from the transformer, and the DC will be on the + and - pins. About $10 + shipping and you are done.

I don't know why I didn't think of this earlier but there is a much easier way to check water levels than using float switches. You use electrical contacts. I know, water + electricity = bad to most people but let me finish.

I could build a really cheap $5 or less circuit that would allow someone to measure the water between two pins. The pins could be stainless steel or anything fish safe and conductive. The amount of power between the two pins would be 1 micro amp or less, very hard to even measure. You could suck on the wires and not be harmed  Then the pins could just be lowered to where you want the limit set. It would trip a relay and turn on whatever was need to fill the tank. There is no direct connection of the tank or pins to the AC wall power so no shock hazard.


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## PfunMo (Jul 30, 2009)

Sleeping here. Let me do a little checking and get back to you. :zz:


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## PfunMo (Jul 30, 2009)

Hi CGMARK-- Glad to see some other input here. I'm not a design guy so sometimes I'm guiolty of just trying it to see if it works. For this case Tokyo would feel much better if we did not go that way! We need to keep it down to the basics for him. As near plug-in as possible. Would you take a look at this and see what you think of it as a supply. 
http://www.spytown.com/mg24vdc1apli.html?productid=mg24vdc1apli&channelid=NEXTA

Seems like it would do the job but if you will take a look it would be great. I think he has the float switch covered now as well as the solenoid. If we can get him onboard with a supply, he's getting close.


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## PfunMo (Jul 30, 2009)

Bump for CGMark-- got any advise here? Others feel free also. Do you see a problem with this power supply for operating a solenoid?


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## tokyo (Jan 19, 2010)

I'm just going to go ahead and buy it. If it doesn't work, no biggy. I need to finish this.

Thanks for the help, hopefully I can get this thing finished in the next week.


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## PfunMo (Jul 30, 2009)

Me thinks it will be fine. But then me thinking could cost you money! I've used that type for a number of different projects as I used to get them free from a burglar alarm guy. I only used them on model railroad projects and Halloween gizmos so none of them ever got much long term use. Good luck with the project. Sounds fun.


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## tokyo (Jan 19, 2010)

Thanks

I'm sure it will be fine, and if it ends up not working, I will have learned something.

*** always liked making contraptions. But i never tried using electricity before. This has opened the door to so many new possibilities.


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## PfunMo (Jul 30, 2009)

I've dabbled in several ares and feel good about doing a lot of things but the electrical is one where I worked with it a lot but never from the design end. At one point the company sent me to school and I got a second class radio license but like most stuff if it isn't something you use, you forget much of it. I don't think anybody does much of the component type work. It's just too cheap and easy to swap a whole board and you can't solder on one without a microscope anyway. Hope you get along well with the project.


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## cgmark (Aug 18, 2010)

Sorry I didn't reply sooner. That transformer will be fine for operating a solenoid. The only thing to watch for is connecting anything else along with the solenoid off the same adapter. Solenoids are basically inductors that release a very high spike of power when they are disconnected. If anything else is attached it could be harmed by those spikes. To absorb the spike from turning off the coil you need a single diode going from - to + on the solenoid. If you are just using it for the solenoid then you can use it without the diode.

This link shows what I mean. It is more about relays but a solenoid is the same electrically.
http://www.bcae1.com/relays.htm
Scroll down to the quenching diode for relays part.


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