I'm working on an project which will be given to some friends and will be open-source too. I need to choose the power supply connector (5V or 12V @ 3A) and I'm thinking to barrel connectors. I found there're 2 version of them, the 2.1mm and 2.5mm for the internal pin.
I read also the 2.5mm male will fit the 2.1 female but connection is not stable, so it is not a reliable solution to choose the smaller one to accept both.
So, which is the most used? The goal is to have the maximum compatibility with existing PSU around the house.