Automatic door invent your own?

[Coopscraft]

Has anybody innovated their own automatic coop door from spare parts? The idea would be to have it close and open either by light or time using electricity or stored mechanical energy. And of course, I want it to be way cheaper than a retail solution.

 

[jthornton]

Of course many have built there own automatic coop doors.
This is the best one I've seen as for simple to build.
DIY Auto Coop Door by @Tsheaby

Mine is complex and controlled by a Raspberry Pi

JT