The sensor detects when infrared light is reflected from the user. A small microchip sets rules to reduce the chance of a spurious activation when a person simply walks past the sink or toilet.
The steps that need to be done for installation are that you first turn off the electricity, wire the fixture, mount it, and then set the rules on the motion sensor light for the on/off switch.
Control Waste With Automatic Toilet Tissue Dispensers. Controlling the amount of tissue dispensed is one of the overarching benefits