Yeah Rbt , I'm was thinkin about those awning motors, that are just the open and closed type systems. These motors are fairly simple, push the button once and it goes up, push it again and it goes down. Now if I can get these to be operated on a timer BINGO ! Everything is in my brain right now. I can visualize what I want, building it is a whole nother thing !  I have seen commercial light dep motors that are REAL expensive ! They operate on a system that not only can be set for the time of day, but also the time that the cover takes to completely open or close. My system doesn't need that.  I think I have thought of everything, but until I build one I can't say for sure if it would be cheap enough for the home grower to afford, but one of my main objectives is to keep it as cheap as possible !!   TBS... look at the $$ spent now for lighting/LED's, electricity, ventilation systems, tents, fans and whatever else plants need to grow ! With my light dep cold frame, other than media, nutes and pots, all you need to pay for, is the small amount of electricity to run ventilation and fans !! Oh yeah, as far as yield potential is concerned, a 4'x8' would yield anywhere between 2-3 lbs per harvest, and you could run two maybe three harvests if the weather permits. The smaller size cold frame could be set up on a apartment balcony, in your back yard, who knows where !! I'm pumped...talk is cheap !!