Editing the firmware with the Arduino IDE
The configuration.h folder is usually the only file that most RepRap printers will need to adjust. This file contains the data that describes your particular electronics and stores the numerical data that calibrates your printer.
The line that is most commonly changed with a working unmodified 3D printer contains the X, Y, Z, and E steps per unit values. These values calibrate the movement of the printer and the amount of filament extruded.
In Sprinter, this can be easily found at the beginning of the configuration.h file. In Marlin, this is closer to the bottom-third of the file. Marlin can be seen open in the Arduino IDE in the following screenshot:
Any data recorded with two forward slashes // is the data that is commented out and disabled. It can also precede comments for information purposes or records. When changing values in the firmware, it's a good idea to comment out your old values with the // for record-keeping in case you would like...
