This is a simple project:  STM8S003 timer for watering plants and LED lighting   It is essentially an clock project with a user interface for setting the alarms. The user interface is a missing piece in my microcontroller library and will be ported to my other projects.

Here is the UI for trimming the RTC by adjusting the values of the timer reload.

https://hw-by-design.blogspot.com/2018/10/stm8-timer.html