I've had trouble with wireless things not working. People have even had trouble with their wireless keys not working for their cars.
The problem is too many wireless "signals" in the air and this can "jam" wireless devices.
Also metal walls, siding, etc. can interfere with the signals.
With that said, I would suggest going to a local home improvement store and buying something there. Then if it did not work, you could easily return it.
Otherwise online... Following is a google.com search for "home automation" and all sorts of web sites selling all sorts of gadgets for this...