https://msalamon.pl/tani-dalmierz-ultradzwiekowy-hc-sr04/
Cheap ultrasonic distance sensor HC-SR04. Project is based on STM32L476RG Nucleo.
This project uses HC-SR04 with Timer interrupts for CPU nonblocking distance reading.
There is another project with simple blocking distance reading CPU: https://github.com/lamik/HCSR04_blocking_STM32