I sorry to be so dense, but where is the locking mechanism? And how handy do you have to be to install this? I have an old sign and lots of lumber and I'm pretty good with building stuff, just not that inventive. I can follow directions would be the extent of my know how! How much room does it need? My coop is a converted play house, and right now we just use the playhouse door, so I'm not sure I have the space for it.
thanks,
Sarah
If you look at the post from N4HHM, you will see the cable from the lift motor attaches to a simple mechanism. Note that the pop door attachment is not a single point, but a plate that rotates as the tension is added or removed from the lift cable. The rotating plate slides a pin, on the right side of the door, to the left, or open, when the lift motor reels up the door. The weight of the door holds the pin in the open position. When closing, the door reaches the bottom of it's travel but the motor keeps lowering and the plate rotates around the bolt in the upper right corner, pushing the pin into the door frame, I assume into a hole drilled for that purpose.
If you are good at building and can follow instructions, the D20 should not be a problem. The wiring is simple and there is an instruction sheet that explains how to hook up the different components. It is a little cheaper as you invest "sweat equity" building the door and buying the timer or photo cell (and battery/solar panel if no power in the coop) and rigging up the pop door opener.
BOTTOM LINE: They all work. Use a timer or use a photo cell, they all work. Use the vertical lift (guillotine) or swing open, they all work. The "open a second time" thingy is a great sales pitch, but it tells me that the door is closing too soon as chooks don't walk around in the dark. Despite the added sales pitch, it also works quite well, especially in applications where the overhead room above the pop door is limited and a swing door is needed. Find one you think you'll be happy with and chances are pretty good you'll be happy with it after you have gone to the expense, time, and effort to install it. Since they all work, each owner is "HAPPY" they don't have to go out twice a day to let the chooks in or out.
The pre-assembled kits basically install over an opening with a few screws. Easy, quick, and no fuss. The others require that you build the door and install the different components to make it work, saving a little money.
BTW, if you do build your own vertical sliding door, make sure the door slides behind a bottom piece so that predators cannot get their little fingers under the door to lift it. That's where the locking mechanism shown above comes in, it gives peace of mind that no critters are going to lift the door. I've never heard on a predator opening an automatic pop door, but with the locking mechanism, they are pretty much guaranteed to fail. I use the same setup but with no locking mechanism. Since my run is pretty much secure, I find little reason to worry about a locking mechanism. But if I were to add a locking mechanism, the one shown above is probably the best I've seen to date.
HTH!
