rope and tennis balls baby
This is a good idea to use on ur greenhouses to do a quick light dep system. This system in this video can be made from metal fence components to make the hinged arm at the ground point. Check out the video below
https://m.youtube.com/watch?v=acPQybj-s7I
I think the best is going Auto. Roll up is cheapest and most simple. Motors are 200$ a piece. You need 2. Couple pieces of emt for arms and you are in business. Leave end walls blacked out.
Or if you want to cover on the inside manually, use cables from end wall to end wall.
Or low tunnel frame about nose height is easy