A few months ago, I wrote a post about the camera obscura , in which he explained the basic principle of photography, which is nothing but the formation of a mirror image to pass light through a very small hole in a dark room.

Based on this principle can make a pinhole camera without more material than a cardboard box and a photosensitive paper. If you want more details about the steps to do it, you can see the video below, where it was made a pinhole camera and shows a picture taken with her.