Not really a product-like project, but I have an esp32c3 controlling our pool's filter and chlorine pumps at my home, and write the software controlling it with the excellent embedded rust esp-hal project and embassy. Having a conversion from straightforward procedural code to a state machine that is usable even without a heap is a fantastic feature to have in a language.

Figuring out how best to control immediate user input and automatic timers has been a bit of an ongoing journey, which I should write more about here.