As Lau explained it, yersterday, we spent a lot of time discussing hardware components. So, today, I carried on searching for rechargeable button batteries, micro solar panel, not rechargeable button batteries which can last a very long time with the memory (32-Mbit DataFlash) and microcontroller we will probably use.
I also continue my work on STM23 board. I am now able to manipulate events ! And material interrupts such as push buttons ! It is thanks to Samuel Tardieu, who helps me to understand how it works – him and some posts in ChibiOs forum. And of course, documentation sources.