Maybe my Googling sucks, but I’ve been trying to track down a transmitter / receiver pair that takes a volt-free input and just transmits it to its partner in another room.

One example: energising undercounter lights when the overhead lights come on. Adding one of these pairs into the circuit would allow lights from two places to be controlled from one switch even if the wiring isn’t present. In my case I want to be able to turn an electric fire on using an Eddi solar diverter.

Is anyone aware of something that does the job? Please don’t recommend the Quinetic stuff.