Yep the CoopBoss was designed from the begging to operate without the SmartThings cloud. SmartThings is only used to setup and monitor the CoopBoss it has nothing to do with the object detection circuit or the auto open and close of the door. If the chicken coop door doesn’t close its a big deal so the CoopBoss is designed to be safe and reliable. You can pull the ZigBee radio out of the circuit and the unit will still boot up, close and open the door as well as detect objects.
When you say leverage the ST hub are you thinking your custom device type is going to run on the hub? From my understanding only ST developers (employees) can write code that runs on the hub. I think your going to be forced to create a cloud based custom device type like the rest of us and you should count on delays between a local event and reacting to it from cloud based custom device type or SmartApp.
I don’t want to be negative I want to help. My solution may not be right that is fine believe me I’m okay with it!!
If I can help I will be happy to. I think your bump switch is your best bet for keeping the cost down. The challenge your going to have with a simple switch is that it will stop your motor just fine (if rated correctly) but that will just stop it in place trapping whatever it bumped up against. I think you will want to reverse the motor so whatever it is pushing against can be released. That gets a little tricky with just a bump switch. I would stick some type of circuit there to reverse the door until it is all the way open. Maybe your curtain controller already has that built in. That would be great!!
Again sorry if I have come across as a negative Nancy here. I admire people who take things on like this!! Thanks for sharing your project and I encourage you to keep it up! Go go go!!!