Hello @terrylu7121!
I’m glad you shared Spooder here, it’s already an excellent robot but I think it’s great that you want to improve it even more and I’m sure you’ll learn a lot along the way.
We are also thinking about using the OAK-D camera with a Raspberry Pi 4 for the humanoid robot but we are also considering using a Jetson Nano with a good webcam, so I invite you to check the Humanoid thread for updates on that.
I see you are already well on your way with the updates so I don’t have much to add other than I hope you have fun and learn a lot by experimenting with it.
Regarding the vision system there’s so much you can do with it, object detection and tracking (people, faces, balls), pose estimation (not sure how useful it could be for an octopod but it might be fun trying to imitate the behavior of an animal), and I think the most useful: localization and navigation. As Coleman mentioned, as it is more of an indoor robot I don’t know how useful it could be using a GPS, but since you are already planning on adding the vision system I’m sure you can experiment with different solutions for indoor localization (check ArUco markers for example) and if you use the OAK camera you could use AprilTags