What software to use to mockup a hardware/software combo with multiple interfaces that interact at once? [on hold]

I'm developing a product that has it's own screen and physical buttons. In addition, a smartphone app communicates to and controls this product. I would like to digitally mockup this entire interaction between the user and between each of these interfaces. What is the best software to use that would allow me to see these three interfaces at once and have them be interactive?

ie. Button in app is pushed, the lights of the physical buttons change, and the display of the product changes.