Add stepper motor (28BYJ-48 is used here)
Add NeoPixel (or white LED) … made a quick acrylic cut with some etchings and wrapped the 5 RGB LED strip around it.
Wire up to Arduino (see the supplied Arduino sketch to see which pins are used for the Stepper engine, which is used for the RGB lighting and another four are used for the buttons)
Programming Arduino  – used CheapStepper- the library for 28BYJ-48 (search for this library in Arduino to download it)
Download the program (stepper motor and lighting NeoPixel)
Stepper motor works well because this cheap engine has little torque and works well, but is quite slow. The other thing I have noticed is that the stepper motor takes a lot of energy and drains batteries quite quickly, and in addition it can get quite hot after excessive use. Can look in to use another type of motor or servo, and maybe have sensors that tell when the aperture is fully open / closed.
Secure everything with a hot glue gun (make sure the wires don't move too much, as well as keep the Arduino in one place and the stepper motor board.
Put the buttons on the board so that you open the aperture, another closes it and the two remaining will take steps in either direction as long as the button is held down.