I need you to check my project diagram

hellow,
I have choose a project through internet, but I am not sure if it works properly. I am upposed to finish the project within 2 weeks so please help me.

this is my project:

- Water Pump Relay Control
Water Pump Relay Control - RED - Page129

I apreciate your help, thank you for your time

Offhand it would appear to work. Do you have a specific concern about the circuit?

Thank you for your replaym Mr.Carl
I did not start to work on the project yet, I got it from redcircuit website so am not sure if it is approved. that is why I have post it here
and yes actually, if I want to add an alarm if it reached low level of water where should I place it?

Well per Carl the circuit will work. However, there is something you need to look at about the circuit. The circuit relies on the conductivity of the water in the tank. Very pure water or deionized water would produce a problem. Another problem with a circuit like this is the probes are steel rods. They will tend to rust a little or corrode, (remember they are steel electrodes) and will need periodic cleaning.

Now as to your question. Note what they say here:

SW1 is optional and was added to provide reverse operation. Switching SW1 in order to connect R3 to pin #11 of IC1D, the pump will operate when the reservoir is nearly empty and will stop when the reservoir is full. In this case, the pump will be used to fill the reservoir and not to empty it as in the default operating mode.

Click to expand...

The circuit can either fill the tank or empty the tank. You could get a signal off IC1D pin 11.

Hope that helps....

Ron

Pin 11 goes HIGH when the tank is nearly empty. Put your alarm on this pin.

Hi Reloadron,

Reloadron said:

Well per Carl the circuit will work. However, there is something you need to look at about the circuit. The circuit relies on the conductivity of the water in the tank. Very pure water or deionized water would produce a problem.

Click to expand...

I measured the resistance of well water at 10KΩ with the probes 5mm apart. Rain water has a higher resistance depending on location. In industrial areas it is most likely sour and has less resistance than living at the coast. At my location rain water is very clean because of heavy rain falls (rainy season) and almost no industry and has a resistance of about 50KΩ.

Another problem with a circuit like this is the probes are steel rods. They will tend to rust a little or corrode, (remember they are steel electrodes) and will need periodic cleaning.

Click to expand...

That problem can be solved using stainless steel, which has to be cleaned at regular intervals because of lime deposit.

I'd be more considered about electrochemical reaction, since the probes are using DC.

Regards

Boncuk

Yes, chemical corrosion can be a problem. The best way to avoid it is to use AC and couple the signal with capacitors.

https://www.electro-tech-online.com/threads/detecting-water-and-probe-disolving.104697/

**broken link removed**

Per the thread Hero was kind enough to link to, when I had the problem I went with enclosed float switches and never worried about it again. That was after years of screwing with all flavors of probes.

Interesting how the conductivity of water changes so much based on geographical location, including well water. I mean, yes, it is to be expected but not something you think about, like measuring the conductivity of acid rain.

Ron

Thank you all for your replay, and for sharing the experience you have, I think this is the best forum ever!

I am still applying everything you have said,

this is the first circuit I do other than the labs circuits, so please be patient with my quesions in next week


thanks again