Turn a phone into a game controller. One device is the big screen (a laptop or TV browser). Phones join with a code and send their motion. This page shows what works on your devices, and how long a swing takes to arrive.
Phones need a browser with motion sensors. On iPhone you will be asked once to allow motion. Nothing is stored, and names disappear when the room closes.
Scan the code with a phone camera, or open , choose the controller, and enter:
Hold the phone like a remote, top edge toward the screen. Swing it like a racket to see the power bar.