I have experience designing hardware projects from scratch, and I have access to the tools necessary for the design stage (I am experienced with the Altium Designer suite, and have worked professionally with it in the past). Obviously this is a bit more complicated than the average project. Once the hardware design is complete prototype boards will need to be ordered and assembled so that the whole thing can be debugged and optimized for battery life. Software design can start at that stage. Ordering say 10x FR4 prototype blanks is around 100$ in cheap shops, but the turnaround can be anywhere from a week to a month. Once you receive the blanks a couple will need to be populated and assembled, by which time the firmware and controller UI should be about ready for testing.
Let me know what you are thinking of, and we can start brainstorming a bit.