Nitram147 from instructables.com has build a ATmega based alarm clock with temperature and humidity reading. Sensor used is DHT11.
First, let me introduce you my project. I made an Alarm clock with extended functionality & thermometer and humiditymeter. Everything started when my friend (who used to bring me some old electronic rubbish and I used to check if there’s not something useful) brought me some cashing register display similar like that. When I first see them I knew that I will made from it alarm clock.
ATmega Alarm Clock & Thermometer Humidity meter – [Link]