Congratulations! From someone who does mixed electronics+mechanical design: this is hard. There are moments of desperation where you realize that everything depends on everything else, and there is no way to achieve all of your design goals. You then have to realize that engineering is all about compromises, and move on, compromising — but this is very difficult. It's easy to get bogged down in details and dependencies and never finish the project.
It's very impressive work and it makes me so happy to see real hacker news on HN. This is real hacking.