# Water Level Indicator

#### Seaker

Joined Feb 3, 2013
32
I am ready for my second electrical project and it will be a simple water level indicator.
The project calls of a 6V AC power source, my question is what would be the cheapest method of providing the 6 Volts AC?
My AC voltage where I live is 220 volts so I suppose a step down transformer would be one solution, what about an inverter or ?

The description and circuit for this simple device is at:

http://www.circuitstoday.com/simple-water-level-idicator

Thank you all for you input!

#### edwardholmes91

Joined Feb 25, 2013
210
Personally I would look for a wall plug that will give you 6VAC. You could use a DC one, but then you have to use an inventor and it probably isn't worth the money.

#### ramancini8

Joined Jul 18, 2012
473
Use a 6V wallwart, and pull it apart to remove the ac to dc parts.

#### DickCappels

Joined Aug 21, 2008
7,251
Since this project involves the AC mains and water, it is a very good idea to make sure that your circuit has a very good connection to earth. It is important because that connection might save your life.

#### KMoffett

Joined Dec 19, 2007
2,918
A very strange circuit. The electrodes will not be driven by AC. Because of the LEDs (and b-e junctions) will act as rectifiers, the electrodes will only see pulsating DC. Electrolytic erosion will happen. This would be OK if the circuit were for just one level, and only alarmed when the water touched the upper electrode.

Ken

Ken

#### Seaker

Joined Feb 3, 2013
32
A very strange circuit. The electrodes will not be driven by AC. Because of the LEDs (and b-e junctions) will act as rectifiers, the electrodes will only see pulsating DC. Electrolytic erosion will happen. This would be OK if the circuit were for just one level, and only alarmed when the water touched the upper electrode.

Ken

Ken
Well there goes the prospect of doing this design for the project.

http://electroschematics.com/5764/simple-water-level-indicator-2/

OR

http://archive.siliconchip.com.au/cms/A_30607/article.html

OR

http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt6.shtml

I do not intend on leaving the unit continuously powered, rather than during the refill stage or to do a quick check on the level.

Using a DC power source is much cheaper than going the AC route, still working on trying to find in insulated wires of Aluminum or stainless steel.
I want a buzzer or alarm of some sort as well!

#### KMoffett

Joined Dec 19, 2007
2,918

#### tubeguy

Joined Nov 3, 2012
1,157
KMoffet's circuit has the advantage of using a Cmos sensing device which has a much higher input impedance (higher sensitivity than the transistor inputs),

And, it's a Schmidt trigger which would provide a more definite and stable on'off indication than the transistor sensors.

#### Seaker

Joined Feb 3, 2013
32
Hello KMoffet, thank you for the link.
I respect your experience and knowledgeable advise that this circuit is a very good option. However as a inexperienced individual to electronics I find it difficult enough to follow schematics/diagrams.
For me unfortunately I am at present unable to form in my mind the addition of multiple detectors as mentioned. I assume from the diagram that the area marked input probe is where one connects the level indicators to but even here I have difficulty as there is two points shown and I would have only a single wire running from the depth indicator in the tank.
I feel that I must have at least four tank level indicators and preferably six to make this project work for me.

Thank you all for the input it is much appreciated!

#### KMoffett

Joined Dec 19, 2007
2,918
Here's my concept. Not tested, but should work.

Ken

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#### Seaker

Joined Feb 3, 2013
32
Hello Ken;
Thank you so much for the effort on putting this together for me!
I will print it up and start getting the components together.

Thanks again

Al

#### KMoffett

Joined Dec 19, 2007
2,918
Need to change the schematic/circuit. I realized that the CMOS gates could not drive the LEDs at 10mA. So I added BS250 P-MOSFETs for greater current drive. If brightness was not important you could use the original circuit with 5.6KΩ resistors instead of the 1KΩ in series with the LEDs. "High brightness" LEDs are pretty bright even at 2mA.

Sorry.

Ken

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