My temperature or temperature/humidity sensor

My needs :
1/ I wanted to make temperature and temperature/humidity sensors based on oregon protocol to have a full compatibility with my RFXcom.
2/ I wanted it to have a low consuption.
3/ I wanted to choose either temperature only or temperature and humidity sensor.
4/ I wanted to use simple and cheap elements : less than 5€ each sensor.
5/ I wanted to put all this in a box i could fix on a wall, inside or outside.
This is all done.

About electronic part :
- attyni85 (low consuption