water detecting circuits

[aliyesami]

hi!
I am looking for a circuit/probe to detect water , can someone point me to one. ??

thanks
Sami

 

[ctownsend]

http://www.discovercircuits.com/PDF-FILES/h2oalm.pdf

 

[dr pepper]

That circuit is good when the apllication doesnt have the probes in water for a long time, if your apllication has prolonged submerged probes then you need a circuit that applies ac to the probes to minimise electrolosys, otherwise your probes will be eaten.
I think I have an everyday eletronics article with one in.

 

[KMoffett]

I agree with dr pepper. A better choice: **broken link removed**

Ken

 

[dr pepper]

Thats an altogether better circuit, the one I had in mind is unwieldy in comparison.
I've added that to my collection of circuits, that would also be cool for use with a micrcontroller (as long as the input is a schmitt).

 

[KMoffett]

Been there...done that...here's the link: 08M Christmas tree watering controller - PICAXE Forum
My PICAXE 08M controlled Christmas tree stand watering system.

Ken

 

[Nik_2213]

IIRC, the problems are just as bad whether the water is ultra pure or tap: One is a fair insulator and the other corrodes non-inert electrodes. You may be better going for float switches or a capacitance-based device. In latter case, the panel electrodes may be insulated...

 

[KMoffett]

I think we're getting way off point. Sami just indicated that (s)he wanted to "detect water". Probably like a flood alarm. Maybe Sami can elaborate?

Ken

 

[vinodstanur]

actually what you mean by water detection?
1>A circuit which detects water and no other liquid
Or
2>A circuit which detects when a water drop fall on a panel.

In case 1 its little bit complicated one and may require complicated circuits.
I think the circuit should confirm the liquid as water by testing some chemical parameters like pH and some thing like that.

The second case is very simple. You can even make it with two or three transistors.

 

[aliyesami]

sorry I had to take a break due to private issues, I back so lets take this issue again .
I am llooking for a way to detect water flow in an salt water aquarium. I want to detect water at the point where its entering the tank since the water pump could be pumping but water not reaching the tank so i dont want to detect pump active or not .
what options i have to achive this ?

 

[KMoffett]

Is the inlet submerged? Can you show us a photo of the water inlet? Is inlet flow normally continuous? What do you want to happen with a no-water-flow indication.

Ken

 

[aliyesami]

the outlet is submerged and the flow is continous, when i detect no water flow i just want to activate a switch .

 

[KMoffett]

Again, a photo would help. Does the inlet line back siphon if there in no flow...whether on pump is supposedly on or off?...i.e. blocked inlet.

Ken

 

[aliyesami]

hi Ken I will try to take a picture, the out does back siphon . basically i want to detect if there is no water coming out of the pipes into the tank.
or i could design something at the submerged pump output to see if its pumping water ?

 

[KMoffett]

Again, without seeing the system, I have no clue. (back to wrapping Christmas presents )

Ken

 

[SWINI]

Sami - May be the second one is easier.. Like if you want to know whether there is water flowing from pump we can do that .. there will be mor intensity of water in that place compared to other levels.. so u can design a circuit where u can put a comparator with one level indicating normal pressure and other the changed one.. this will send signals if there is any flow inside..

 

[aliyesami]

swini iam not sure i understand . .can you please explain ?