LabVIEW
Autofilling Water Pitcher
A pitcher does not have buttons. As I first step, I recommend to leave out any hardware (valves, flow sensors, etc.) and work out all the logic in a simulation.
Create a proper state machine with the desired buttons and their desired mechanical actions and a tank indicator to show the fill level. What is your LabVIEW knowledge? Your "plan" is very vague. Did you do any basic tutorials yet?
A state machine is the way to go here. Think though your states well and I think you'll be able to implement it easily enough. Off the top of my head, an "Idle" state and a "Filling" state should do most of what you want. Transitions from Idle to Filling would happen whenever you clicked a button. In Filling, watch your flow sensor and integrate it. Once it reaches your target value, transition back to Idle.
I'd start by making it entirely manual- keep both states, but transition only with a "manual" button. Once that works like you want, add the flow sensor but only to monitor- show the value on the front panel. Once that works, you can add logic to switch based on the integrated flow sensor reading.
(Or you might find it easier to do a weight-based sensor, as scales are super cheap, are often easier to read than a flow sensor, and you don't have to do any integration.)
