Hello! I have started projects where I do not need to transmit serial data however the serial library still forces me to declare both a TX and RX pin. I modified the Software Serial library to only receive data and was able to save about 500 bytes (and a pin!) on my ATtiny85. The modifications were inspired by Nick Gammon's SendOnlySoftwareSerial (which works great!) http://forum.arduino.cc/index.php?topic=112013.0
Unfortunately, I am not a lawyer and I am unsure of the proper etiquette on how to mark my changes if I were to "publish" the modified libraries. If I could get some guidance, I would love to contribute this library (it is still being tested though!).
I have tested the library and it seems to work. Just make a folder called ReceiveOnlySoftwareSerial and place the three attached folders into it. Then place that folder into your arduino/sketchbook/ibrary folder to "install". It works exactly the same as SoftwareSerial except you only need to specify one receiver pin during initialization. This is also my first modified library, any pointers/tips would be GREATLY appreciated!