Water Valve Project: Adding Blynk control to previously written code

[PeteKnight]

@Blink_tynker

My question is, can I incorporate Blynk to this existing code in order to add mobile connectivity and control to this project ?

Not really. The code in the link is a demo that seems to move the valve from one location to another then waits 45 seconds, then moves it back.
The wait process, and the sampling delays on the opening process, which seem to be for calibration) use blocking delay() commands. These aren’t compatible with Blynk.

The example is simply a calibration and demo sketch, not a working solution that can then be 'Blynkified".

@Blink_tynker

Do I create the blynk interface and just add it to the existing code? If so, could someone point to some tutorials on how that’s done.

You need to understand the process of getting commands from the Blynk app into the sketch and using them to perform the actions you need.
I’d suggest that you use virtual pins on the widgets that you choose for this. You may find this tutorial useful:

Using Virtual Pins to control physical devices

I thought I’d write a guide about how to use virtual pins with app widgets such as buttons, to control physical devices such as relays, LEDs etc… Why use virtual pins anyway? I’d always recommend using virtual pins over physical pins when developing your code. There are a number of reasons, but here are what I consider to be the main ones: Virtual pins are hardware independent. This means that it’s far easier to port your code from one hardware platform to another in future (when you realise…

@Blink_tynker

Or do I have to start from scratch and write new code just because I’m using Blynk (If so this will take much longer as I would need to learn how to rewrite this code for blynk)

Looking at that example sketch, I’d start from scratch.

@Blink_tynker

with a second ‘display’ of some sort that shows the valve did OPEN, did CLOSE or is MIDWAY

Maybe LED widgets to mimic those physical one you are thinking about using?

@Blink_tynker

In the attached schematic, The valve’s black wire is connected directly to the AC24V ground, which I don’t have as I will go from 120v AC to 24vdc and the schematic does not use LEDS for display.

Well, first of all, I don’t understand the schematic. It’s colour coding is somewhat bizarre, as is it’s use of what I assume are grounplane symbols.
Secondly, I don’t understand your comment comment about you not having the “black wire”.

There is no GND with an AC supply, unless you’re referring to the mains GND, which should be at the same potential as the mains Neutral.
The way to control physical LEDs is to connect them to GPIO pins on your ESP32. Depending on your LEDs, you will probably need a resistor to drop the 3.3v to a voltage which is acceptable to the LEDs, and to limit the current. There are plenty of online calculators for this, simply input the parameters of your chosen LEDs (and remember that different coloured LEDs tend to have different parameters, so different resistor values may be required for each LED.

Pete.