water level indicator

[deepakgupta.rf]

hello everyone
i have made water level indicator based at cd 4066 there we put 4 metal screw and wired to our kit.
in that one is +12v supply and rest three are inputs. and at last one we use relay for loud siren.
but there we are facing trouble with earth problem.there earth making flicking in realy and relay flicking very fastly and we are feared also that is that current we leave in water current can make any trouble when we use water or get any shock.
here i am attaching a file for this but here after bc148 i used a 12 v small relay for siren so this realy is getting flicked.
please solve my problem

 

[poor mystic]

Hi deepakgupta.rf
It's a little hard to penetrate your grammar, which is unique.
However, I wonder where this other current might be coming from and I think you should sort that out first.

PS Be very sure that everything is well earthed!

 

[dauntless]

Hi all, water level indicator based at cd 4066

I have made the below circuit for a school project and found the 4th LED (Full) is not lighting when the full probe touches water level. buzzer is ringing. also all other leds (3) get extinguished. Just extended the reference probe (common 6v) near to the 4th LED (full) probe and extinguishing problem (other 3 leds) solved and still the full led did not light up. any help????

hello everyone
i have made water level indicator based at cd 4066 there we put 4 metal screw and wired to our kit.
in that one is +12v supply and rest three are inputs. and at last one we use relay for loud siren.
but there we are facing trouble with earth problem.there earth making flicking in realy and relay flicking very fastly and we are feared also that is that current we leave in water current can make any trouble when we use water or get any shock.
here i am attaching a file for this but here after bc148 i used a 12 v small relay for siren so this realy is getting flicked.
please solve my problem

 

[shrtrnd]

Make sure your grounds are correct. As poor mystic mentioned, make sure you're
not picking-up stray current flows. If you've got a voltmeter hooked-up to your circuit,
disconnect it for circuit operation. Any strong electromagnetic fields in the vicinity
of your circuit, move them (Power supplies, other emf generators).
When I built my water/water/level sensor circuit, I found you needed 'dirty' water that
has conductive contaminants in it. The cleaner the water, the less reliable the contact
connections to the 4066. Good luck.

 

[dauntless]

Make sure your grounds are correct. As poor mystic mentioned, make sure you're
not picking-up stray current flows. If you've got a voltmeter hooked-up to your circuit,
disconnect it for circuit operation. Any strong electromagnetic fields in the vicinity
of your circuit, move them (Power supplies, other emf generators).
When I built my water/water/level sensor circuit, I found you needed 'dirty' water that
has conductive contaminants in it. The cleaner the water, the less reliable the contact
connections to the 4066. Good luck.

Thanks.
No luck. just removed the full level LED and adjusted the project report with 3 level led and just buzzer for full level.

 

[DLD]

I had used 12V DC source or 230V AC main from 12v Adaptor.
But I used three sensor built from non-corrosive particle (metal).
http://files.spogel.com/abstracts/p-1510--simple water cont1.pdf
http://files.spogel.com/abstracts/p-1510--simple water cont2.pdf
Thanks

 

[duke37]

There will be no danger if you are using an isolated 12V supply.

The 180k resistors could be raised to say 1M if necessary which may make more reliable operation.

The 2.2k feeding the BC148 is very low. The BC148 could be replaced by a fet or a darlington transistor with a high value drive resistor.
A Darlington can be made with a pair of BC148.

More reliability would be achieved if a positive electrode were placed near each sense electrode.

 

[Arouse1973]

Why don't you put the buzzer across the 4th LED and resistor and get rid of the transistors? That's assuming is not a 100dB sounder that draws an amp or two
Adam