Try this arrangement.

The decal for K1 seems off. The pinout is correct, but the location of the coil relative to the normally closed contacts is, let's say, not intuitive.

ak

 

Try this arrangement.
What are SW1 and SW2 for?
As wired they will shut off the Relay and Pump when pressed


View attachment 369318

D1/R1 has a very low operating current. Assume a 2Vf on a 5V source, 3V would be 1.4mA. Assume a 3Vf on a 5V source, 2V would be 0.9mA. That DOES look like a 2.2KΩ resistor. Changing R1 to 200Ω in either example would yield 10mA or 15mA. As far as off current draw, that would be nearly zero µA (depending on the leakage current of Q1).

 

SW1 allows me to turn on the pump from the transmitter.
SW2 allows me to turn on the pump from the switch when to boat is out of the water.

 

SW1 allows me to turn on the pump from the transmitter.
SW2 allows me to turn on the pump from the switch when to boat is out of the water.

In that case SW1 and SW2 will be wired to +5volts, not ground.

 

OK on that. I don't have them in the circuit right now. I can add them later.

I tried the circuit as B-Jo-Jo-S said. Not working. I measured 5v where the two probes are connected. Can I short the probes together to see if the probes are a problem?

 

I tried the circuit as B-Jo-Jo-S said. Not working. I measured 5v where the two probes are connected. Can I short the probes together to see if the probes are a problem?

What circuit was that?
The correct circuit is post #84.

 

Yes post #84

 

Yes post #84

Are you saying the circuit in post #84 is not working?

 

I tried the circuit as B-Jo-Jo-S said. Not working.

Could you quote my comment so I can review it and see if I said something incorrectly? Thank you.

 

Are you saying the circuit in post #84 is not working?

Correct. When I immerse both probes in the water the pump does not activate.

To be clear,
when the low probe is immersed, pump should not activate
when the high probe is immersed, pump should activate
as the water drops, pump should shut off once both probes are not in water

That was the idea in the beginning of the discussion.

Could you quote my comment so I can review it and see if I said something incorrectly? Thank you.

Um, at this point I'm not sure. We are working off the circuit in post #84 that sghioto changed.

 

Correct. When I immerse both probes in the water the pump does not activate.

Do you have a volt meter?
I think I know what the problem is.

 

I have a voltmeter and scope

 

Um, at this point I'm not sure. We are working off the circuit in post #84 that sghioto changed.

That's a good circuit. As long as your motor runs satisfactorily on 5V. Then again, I don't readily see a reason for using a 5V regulator. But somewhere in this thread you may have said your motor can run on 12V. Sadly, I don't have time right now to review all five pages.

 

I have a voltmeter and scope

Read the voltage on the Base of the TIP120 with the high probe in the water.

 

The base reads Øv, the collector is 5v

 

The base reads Øv, the collector is 5v

Would not have expected 0 volts.
Read the voltage on both ends of the high probe and R2.

 

Sorry, with all the touching of things a wire popped out I did not see. That reading is 1.32v.

Now with the high probe in the water the pump/LED turns on.

And it operates as it is supposed to!
when the low probe is immersed, pump/LED does not activate
when the low & high probe is immersed, pump/LED activates
as the water drops, high probe is dry, pump still runs
when low probe is dry, pump turns off

The voltage at the pump is 4.85 volts. Current draw at the power supply is 0.187 amps.

This is the pump I am using... https://www.amazon.com/dp/B08QTS5YRN?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

 

Great, nice to see it's working.

 

Tanks for all that helped.

I'll add SW1 and SW2 in now.

 

Work's fine with SW1 and SW2.

Can LED's be added so that visually I can see that the low or high probes are active?