After a long time tweaking my new 3D printer I solved all the unexpected errors and I can print succesful pieces but I am facing a "problem", they are over sized, I found this problem trying to print a Raspberry Pi Case and an smartphone case, the printed pieces are bigger than the objects.
Here some related information
Printer: Geeetech Prusa i3 Pro B
Firmware: My GitHub (Marlin)
Software: Repetier Host with Slic3r
Does somebody know how could I solve it? Thank you very much