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),
- DS18B20 (temperature sensor), DHT22 (temperature and humidity sensor),
- simple chineese low cost 433MHz emetter,
- 3 AAA batteries cheap support (i did not have a printer when i started this project..., one can make its own),
- put a 10uF capacitor between +5v and ground,
- emetter data pin on attyni85 pin 2,
- for a DS18B20 : VDD on attyni85 pin 3 and DQ on attyni85 pin 4, and 4.7k resistor between VDD and DQ,
- for a DHT22 : VDD on attyni85 pin 3 and DATA on attyni85 pin 4 (simpl