Where exactly are you going to put a power supply in a room? Make a special electrical box for it?
Switched-mode power supplies can be as small as your average Arduino board. They can fit inside the space used for wall outlets or light fixtures. Or you can put the DC transformer inside the light switch.
Switched-mode power supplies can be as small as your average Arduino board. They can fit inside the space used for wall outlets or light fixtures. Or you can put the DC transformer inside the light switch.