What is the difference between a smart switch and a smart relay?
Smart Switch: A smart switch as the name implies is a simple switch, it supplies 110v when activated to the end device. A smart switch sends full voltage (110v) to turn on or turn off a device. For example: if you want the light in the room to turn off, you turn the light off (open the switch) and the light turns off. A Smart switch can be automated OR may need manual human intervention
Smart Relay: A smart relay blends into the circuit and acts as a switch within the circuit. One example would be a situation where you need a circuit opened or closed, but not 110v passed through. A relay is kind of an automated switch which is controlled electronically. So if you have light which you want to turn on and off through motion sensors, The signal from motion sensor feeds the relay and the relay would have to control the light