water level detector.

Thread Starter

vivek.raunak

Joined Oct 23, 2010
29
hiiiii

i am doing project on water level detector.......
i need some modification.......
can u suggest some?
i have attached my circuit diagram here....
 

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Thread Starter

vivek.raunak

Joined Oct 23, 2010
29
hi,
i want to control water level of the tank automatically,
mean if water would fall below an specified level motor should switch on automatically.......
and in the same way if water starts overflowing motor should switch off.
plz suggest me an idea....
 

JDT

Joined Feb 12, 2009
657
You need a latching circuit. Also known as a SR latch. Two NAND gates cross-coupled are a classic implementation of this. Half of the familiar "4013" can also be used (tie the D and clk inputs to 0V). Use logic on each input to the latch so that it will be set when the water level gets below a certain point and reset when it gets up to another point.

Control your pump via a relay so that it is isolated from your level detector circuit.

Your level detector circuit will work but suffers from a problem that only DC is used on the probes. In time there will be electrolytic action that can cause corrosion. Better detectors (all commercial types) use AC.
 

bertus

Joined Apr 5, 2008
22,270
Hello,

You could feed the outputs of the desired and ports to a flip-flop.
The flip-flop cab control the motor over a power stage.

Bertus
 

Thread Starter

vivek.raunak

Joined Oct 23, 2010
29
hello sir,
very very thanks for your precious suggestion .........

u mean to say corrosion takes place inside the tank...........
but what if i use an inverter ?
it will convert DC signal into AC.

how the commercial level detector is made?
 

kcarring

Joined Jan 22, 2011
38
You might want to look around for a more corrosion resistant style well nut. The typical RV water storage tank well nut doesn't hold up for more than about a year. As an RV technician, I am all too familiar with this. The circuits on RV have a resistor block, and the panel detects the different levels based on resistance. Unfortunately, the meters start to lie, sooner than acceptable, usually based on the well nuts failing to do their job properply, as mentioned earlier: corrosion.

It may be that stainless hold up better. I do know kayaks have some. Research and see if a better well nut is available. (If that's what your using)

http://topkayaker.net/topkayakersho...ducts_id=142&zenid=008dn80jv4iea99q104fgs62d0
 
Last edited:

SgtWookie

Joined Jul 17, 2007
22,230
You might find something like the attached circuit more useful and easier to build.

C1 is a pair of conductive plates with a surface area of 12 square inches, or roughly 30 square centimeters space 0.1" or 2.54mm apart. It could be any shape; circular, a long strip, rectangular - just as long as the surface area and spacing are approximately those dimensions. The plates could be single-sided raw PCB stock. They can be conformal coated so the water cannot contact the copper surface.

With no water between the plates, the output will be a logic low. As more water comes between the plates, the output starts to generate pulses. When the plates are completely covered with water, you will see a square wave output.

This is an inexpensive and simple circuit to build.
 

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