Pinhole

If you make a small hole in a light-proof box, the hole will let light through in such an order that inside the box there will be an inverted image observed by the camera. This hole is called pinhole, the phenomenon of inverted image is an effect known as camera obscura. This concept can be freely developed by experimenting with the size and shape of the pinhole, the distance of the pinhole from the light-sensitive element, or experimenting with curvature. An extreme case of pinhole is Solarigraphy, which involves months of exposure and centers around recording the sun's travel....

My first camera was created from a peanut can and as a proof of concept I took pictures through a window.