Typically, there is zwave plug measuring the power draw and sending data to hub. Based on the data, an event is triggered to change an LED on a light switch. H

Typically, there is zwave plug measuring the power draw and sending data to hub. Based on the data, an event is triggered to change an LED on a light switch. HomeSeer has zwave switches with LEDs used for dimmer feedback than can be programmed to show a color. I use the LEDs on one switch to match the state of two exterior door locks. Green/unlocked and Red/locked. I use another LED on the switch to match state of the Litter Robot, automatic cat litter box. Blinks red when full and needs to be emptied.