This is the same underlying idea as your car's windshield washer fluid warning light, sense how much liquid is present and report it. We'll wire up a resistive water level sensor strip, read it via ADC, and print a live percentage-style level reading over UART.

2. Scope

We'll wire the sensor's analog output straight to the ADC (most modules already include their own onboard divider circuitry), and print a continuously updating level reading. This is another good reinforcement of the voltage-divider-plus-ADC pattern, now applied to a third different physical sensing need.

3. Prerequisite

3.1 Hardware

• STM32 Nucleo-F070RB development board

• Resistive water level sensor module (exposed parallel trace strip type)

• Breadboard and jumper wires

• Micro-USB cable

• PC with PuTTY

• A small container of water for testing

3.2 Software

• STM32CubeMX (standalone)

• STM32CubeIDE

• ST-LINK USB driver

• PuTTY, or an equivalent serial terminal app