Camera parts to be 3d printed

I am building lens-less (pinhole) cameras. I have designed and 3D printed the first prototype and need someone to design additional parts. The first of these is an assembly so that the photographer can press a button/pull a lever to allow light into the camera and then block it when the photo is ready. I need the assembly to be made of 3D printed parts and available hardware.

The assembly needs to fit within and operate within a diameter of 2 inches or 52 MM.

Thank you reading and bidding.