Today, the greenhouse itself has seen some major improvements. The bottom half is an old sandbox I picked up a few weeks ago at a garden store. It was moist, the glue had come loose, so basically it was an instable pile of wood. I managed to put it back together, with screws and added weed cloth on the bottom. Then I reinforced the sides and the bottom with wood I had lying around from an old bed. Since it is untreated wood, it will probably not hold forever, but since this is a prototype I do not mind so much.
This is the bottom of the greenhouse box with weedcloth attached
The top half of the greenhouse is the glass part, which is not actually glass, but some sort of double sided transparent plastic. The whole frame is aluminium. As you have probably guessed: this was bought, not made by me 
After finishing the box and reinforcements to the bottom, it was getting too dark to snap a decent photo, so that will have to wait for later. But I will finish this post with an image of the top half:
Light:
Moisture:
