I just started experimenting with using an Arduino and various remote system protocols (IR, Bluetooth, Low Freq RF, sound/light activation, etc) to control a relay to turn on/off a simple desk lamp. It's a plain jane desk lamp that originally had a filament bulb, I've stuck in an LED bulb.
I chopped the AC live wire and stuck it into the relay, things are working okay. Both relay and lamp switch have to be on for it to be on, or either of them off will have it off. Like they're just two switches in series, really. Perhaps the reverse would be preferable- both have to be off to have it off, but only one needs to be on for it to be on.
I'm wondering what the best ways are to keep the original on/off switch on the lamp still functional. So if the relay is off, the lamp can still be turned on/off with its switch. Or even true 3-way functionality where either one can turn the lamp on or off interchangeably if that's not too complicated.