In a previous article, we had use an Arduino + RF433 chip + DS28B20 to come up with a cheap temperature sensor.
We are going to improve the setup by replacing the Arduino Pro mini by an ATTINY85.
See here on how to flash an ATTINY85.
See rf433_sendOOK_at85 for the code.
Note that power consumption will be as low as 0.005ma (5ua) with a peak at 18ma when reading temp.
See below a revised wiring replacing the Arduino by an ATTINY85.