System Diagram: components and implementation
Wall plug on the dock, (rechargeable) battery on the device.
The information requirements:
Wi-Fi, HDMI cord to TV, phone app
Device in the physical space or the human body:
The charging hub would be near the TV. The main component could be anywhere, floor, coffee table...
Power button (push)
Volume knob (turn)
App controller (button pushing, dial sliding/turning)
Motion detection (gesturing, positioning)