The motor shield can handle up to two stepper motors at a time. This might be useful in a large room with more than one window. The curtains’ pulley systems can also be linked together so that a single stepper motor could open and close multiple curtains/shades. Going even further, the stepper motor/motor shield combination can be employed in a number of other home automation scenarios.
Elaborate on the curtain pulley with more sophisticated curtain rod systems that have an interior up/down window blind and exterior left/right curtain draw. Time one motor to raise/lower the blind followed by opening/closing the decorative exterior curtain. Modify these two configurations based on heat and light (i.e., if hot daylight, open curtain ...