On the day of the solar eclipse I improvized a camera obscura in the office. It’s not nice, but functional and took only 10 minutes to make it. It was great fun to see my colleagues tucking their heads in the box to see the phenomenon.
I got a cardboard box from the store. I used a piece of plastic (cut out
from a 3.5” floppy disk) to create a thin slit. The slit is fixed over a
hole I cut in the side of the cardboard. An office chair provides the support.
I glued a white sheet of paper in the box, on the side that is opposite to
the slit. The image of the eclipse is small, but surprisingly sharp.