This Arduino lights dimmer project is based on Doug Hitchcock’s comment: “I need to have a lamp dimmer that can “cascade” from one lamp to the next (up to 4 lamps). Basically, when you close a switch, ...

Now suppose you have a 100 Watt light bulb. Then, each time you switch on the light, you burn 900,000 watts, or nearly a megawatt of power. Mind you, that would be only for one fifth of a second.