Water pump controller: Need some verification and tips

Hello there guys...

Just a little unsure of the fine calculating with this.

Is this circuit useable. And im not sure of the correct components.

See attached image of circuit.

I will work on the code later. First I want this circuit to be ok. Arduino will be powered from this circuit.

The plan is to use this on a pump in a room in my basement where there is always water coming in. And want the pump to start when water high is triggered, and stop when water level hits water low.
The sensor s is just plain wires that will trigger the NPN transistor and give a signal to arduino.

How much current do those relays need for operating properly?

If they need a fair bit of current, then the arduino's digital outputs won't be able to supply the amount of needed current level.

Also, you may need to see whether those sensors for the water level will turn on and turn off cleanly ----- such as not turn on-and-off repeatedly if the water level is at 'border' ------ the interface between high and low that is. Maybe for your case it's all ok. This is just referring to 'chatter' and hysteresis.

The right hand terminal of the relays (cathode of the 1N4148) go to a positive relay power supply, ‘NOT’ an Arduino I/O pin. See Q5 cct. below.

Made sure your sensors have a base current limiting resistor.

Thanks Larry.

Your led current limiting resistor are in SERIES with the relay coil current. The leds and resistors should be connected to the I/O pin that drives the
base resistor for Q1.

I would connect the LED and It's current limiting resistor right across the coil,

and not in series with it

In parallel is fine.

Thank you guys. I see where i can improve. Will come with updated drwaing later on:)

Have redrawn the circuit. Hopefully catched all your tips

Your indicator LEDs are reversed. You want the cathodes low side.

Personally I would not use your level sensor scheme. How well it works will be a function of the conductivity of the water. Another problem is the exposed wire in the water will build up corrosion. One big problem with using probes in the solution, you will be constantly cleaning the probes. Personally I would go with stainless steel float switched which can be had for about $10 USD each.

Ron

Your indicator LEDs are reversed. You want the cathodes low side.

This is a reference to the ones you put in parallel with the coils, not the other ones.

What are resistor and voltage values? If neutral (N) wire is grounded, you don't need to (shouldn't) switch it , just one relay on the "HOT" line.

What are resistor and voltage values? If neutral (N) wire is grounded, you don't need to (shouldn't) switch it , just one relay on the "HOT" line.

Actually, I think it is considered unsafe to switch the neutral but I'm not an electrician so I could be wrong about that. I agree there is no point in switching the neutral as it gains you nothing. No current can flow if the L is not
connected. Neutral is simply a return line.