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Associate

Join Date: Jul 2007
Posts: 26

water level detecter

06/18/2008 12:05 PM

i am building a project to dectect the level of water in a tank using a microcontroller basically all i want to do is to put a switch in the tank that will close when the water level reaches that level so that the micro can pick that up and switch a relay off. i have finished with the program for the controller and everything works fine but my problem is the switch that i will place in the tank.Is there a switch i can use other than a probe? please help

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Guru

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#1

Re: water level detecter

06/18/2008 12:17 PM

Floats..

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#2

Re: water level detecter

06/18/2008 12:48 PM

Bulb float switch for a sump pump.

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#3

Re: water level detecter

06/18/2008 3:37 PM

There are loads of float switches out there. RS Farnell, Digikey will all have 'em.

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#4

Re: water level detecter

06/18/2008 10:45 PM

for jetted bath control systems, we used to use a capacitive sensor that was designed and built by us.. basically it was a fully plated circuit board in a plastic box, placed on the outside wall of the fiberglass tub, and the other half of the 'capacitor' was connected to the drain. When the water was high enough to switch the state in the tuned capacitor circuit, the circuit had then 'detected' the water level at that level where the 'sensor' was positioned.

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Active Contributor

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#5

Re: water level detecter

06/18/2008 10:54 PM

Is this for fun and home or is it for real? Are you putting people or capital in danger? The suggestions above are just fine - float switches are about as cheap and standard as you can get, and they work. The cap sensor is a great way to go AND you dont have floats and things getting fouled. There are other more sophisticated sensors out there, but your syntax implies a desire for drop-dead cheap, so being careful should also be on your list....

dj

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#6
In reply to #5

Re: water level detector

06/18/2008 11:10 PM

Program? Using a pico relay or other processor and is this just an exercise in writing code? Or--Are you hard wiring and needing to maintain liquid levels?

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#7

Re: water level detecter

06/18/2008 11:46 PM

Hi there.

I am rohinton from India. We do get float switches to control water level. Available in 12, 24 V DC & 220V ac. Floats are available in nylon, Pu foam, stainless steel etc. We use for our controlling water level in our own design PRE COOLER for air conditioner. Called Genie The Power Saver. we buy switches from Shridhan international in India. You may check the site www.shridham.com.

If you need more help contact me

Regards

Rohinton Panthaki

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#8

Re: water level undefined

06/19/2008 12:53 AM

Hello gdallas2,

you did not say if you also wanted to control the water level. I note you mention a microcontroller. The Royal Society for the Blind make a very cheap and simple device for telling you when the water has reached a certain level in a bath. Is is battery powered with a buzzer. Very cheap, and you could just hang it on a length of string, (if you want really cheap!).

jfmfit

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Guru

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#9

Re: water level detecter

06/19/2008 3:38 AM

Didn't we have this question a few weeks ago?

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Power-User

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#10

Re: water level detecter

06/19/2008 9:08 AM

As others have said, float switrches are the cheapest probably. However, if you want to eliminate the electrical current being in the water, you can use a pressure switch such as manufactured by Mercoid and others. Some of these are relatively expensive, while a simple low-pressure switch can be as cheap as a float switch. It would require a tube be placed in the water and the setting adjusted. When the level gets to the level you have set, the pressure switch would close. These closing contacts would be located somewhere other than in the water.

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Anonymous Poster
#11

Re: water level detecter

06/19/2008 11:43 AM

You could use an optical transiver system to level control.

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Associate

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#12

Re: water level detecter

06/21/2008 4:23 PM

hi gdallas2, in every household washingmachine there is a switch to control the waterlevel. Its basically a 6 mm (1/4") rubber hose connected to the bottom of the tank and the switch, which is placed at the desired level outside the tank. When the water reaches the max level, the airpressure inside the rubbertube pushes a membrane which is connected to the switch, and you have your level switch without electricity in the water, and, may I add, very affordable, if you can get your hands on a machine to be dumped.

I plan to use a couple of these switches to control waterlevel in a drain-back solar water heating system, because the open expansiontank will be placed just under the panels inside the attick, and not easily accessable. If level is not right, both running and still, I will get a warning light.

Good luck with your project

moe

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Anonymous Poster
#13

Re: water level detecter

07/27/2008 10:56 AM

IFM Effector makes some really good 24vdc programable level detectors.

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