I am an engineering student tasked with building a gas liquid level system for my final project (level 1), I have to pass to go to level two. I am facing difficulties with picking the right parts. My idea is for it to be non invasive, magnetic so that it can be put under the cylinder.
Remote controlling,mobile app,alarm system, connected to the phone via Bluetooth.
Any ideas will be deeply appreciated, thank you ????

I did research on sensors and ended at using ultrasonic sensors, I already have a battery in mind, I’m looking for an alternative for arduino