A modified version of the official Arduino library exclusively for the stepper motor 28BYJ-48 (with the board ULN2003) as the official version doesn't work properly with this stepper motor.

This Arduino library is used to control one or more 28BYJ-48 stepper motors. These motors are very small with a built in gear reduction. The advantage of these motors is that they are inexpensive and ...

Motion is provided by a 28BYJ-48 stepper which is connected to the drive nut by way of a belt. The spinning nut is used to raise and lower the threaded rod which opens and closes the “door”.