Hello,
the task looks amazing, I would like to help you, in both programming MCU firmware and electronic circuit development. It would be fine if we could contact and exchange details. There is also an option to adapt the budget estimate.
Best regards,
Viktor Gotwig,
Cologne, Germany.
P.S.: About the milestone: the freelancer.com behaves strange, so I do it firstly as "project architecture design", we can adapt it later.