After many weeks of waiting for parts, and then weeks of trying to make parts work right, it’s finally done. The chicken coop has an automatic door on a timer so my wonderful, patient girlfriend can get more sleep!
It’s super basic. Retractable car antenna from Amazon, two 12v 5a power supplies, and some maguyvering. The antenna has three wires. You attach the grounds for both power supplies to the black wire, and the hot wires to the remaining two wires respectively. When they’ve both got power, the antenna is extended. When only one does, it retracts. Oversimplified, but you get the idea. So one power supply is on a timer and the other isn’t.
For some more detailed instructions, check out this thread at Automatic pop hole opener on backyard chickens.
Additionally, I have installed three nest boxes since the chickens started laying. And even better, they’re actually using them! We’ve had three more eggs since the first two, but what makes it cooler is the timing.
On Wednesday, making breakfast, the girlfriend realized we were out of eggs and was worried she had to run to the store. It had been over a week since the first two so neither of us expected to have any, but lo and behold the Bielefelders are just that courteous.