Most "smart water tank" projects are Arduino + ultrasonic sensor + buzzer, wired together in a single loop(). This one reaches for something more interesting: an STM32F446RE running FreeRTOS, where the level sensing, alert logic, and user feedback are separated into discrete tasks coordinated by the kernel.

That framing matters. A water-tank monitor is the kind of small, bounded problem where you can actually see why an RTOS is useful — you have a slow sensor read, a time-critical alert, and a UI that all need to coexist without blocking each other. Doing it on bare-metal Arduino-style code forces you into fragile timer ISRs and state machines; doing it with FreeRTOS tasks, queues, and semaphores is the textbook example used to teach preemptive scheduling.

The STM32F446RE (Nucleo board) is also a solid choice — it's the same Cortex-M4 platform used in a lot of professional embedded curricula, so the techniques transfer directly to industrial work. Expect to see task creation, inter-task communication, and probably priority assignment for the alert path.

Caveat: this is a 1-subscriber channel and likely a student project, so production polish will be limited. But for someone learning the jump from Arduino's loop() to real RTOS-based firmware, watching a peer work through a concrete example is often more instructive than a polished tutorial.