Very nice!
I'm doing something similar (in C# though). I'm using a FET as inverter for the RX signal. Hopefully I can test my setup in the coming days to see if it all works, I have completed most code so its a matter of debugging :-)
Now I just need to find a suitable home automation system to log the data too :-) Too bad there arent any big open source projects on .NET going on for this :-(