This is the chicken coop door controller. When it gets dark at night, then hens go in by themselves, then the door shuts when the light reaches a certain level. In the morning it gets brighter and the door opens again. There is some hysteresis to stop it from going up and down. The electronics are simpler (ish..) and there is software running on a PIC16 to do the slightly clever stuff. I might write about it some time later, but for now I’m trying out this album plugin for wordpress.