You know those days when lifting a finger to scroll a website seems like to much of an effort? No, of course not, me neither. But just in case I made this so I can scroll just by leaning back in my chair:
If you look closely there's Adafruit's Feather nRF52840 Sense board attached to the back of the chair. It uses the onboard sensors to figure out the angle of the chair's back and if it's over a threshold it sends scroll down events to the computer (using the standard Bluetooth mouse protocol so it works with any OS). To set the "zero" position you press the "user switch" button on the board.