It seams you have a problem working out Fritzing, and that the circuit doesn’t work based on your interpretation of the SCH.
I would start again and do the SCH first using the LM324N - there is a LM124-324 in the core bin -. Then check that every connection to a pin is green, and that every junction is actually connected by grabbing the junction and moving it and making sure all the wires move with it.
Then go to the BB view and trust the ratsnest. You can click on a pin on a part and every place it can connect to will turn yellow, so run a wire between those two points and the ratsnest should disappear.
Hopefully this will show if there is an error in your original BB layout, and why the Ard isn’t getting enough signal.
I just noticed your R2 20K pot is missing.
What’s the story, this has been posted 2½ years ago.