So far I am figuring out which low voltage 555 version I'll be using.  As anyone trying to replicate this project might know, its fundamental to find a low voltage substitute of the classic 555 IC, since this chip in the standard version needs at least 5V to power on. So, I'ts important to choose between the different options based mainly on availability, cost and operation voltage.

In the next days, I'll publish which one was my choice.