previously mentioned about an arduino sketch which can gather data from various sensors and push them to my home automation & personal assistant software called "Judith"
Today i implemented one LDR and BMP180 barometric pressure sensor. LDR's are really old technology, even was exists inside of automatic night lamps at my childhood. i suppose they're just reacting too dark or lighter environment but surprisingly i found this one very sensitive. it can detect light changes step by step while sun goes down at the evenings. currently judith controlling hallway and my rooms light switch based on her own day & night calculations. i will use this data as correction value for cloudly days which light will be needed at a rainy day.
Bosch's bmp180 barometer unit is really small even exists in motorola xoom tablet. you can calculate approx. altitude from pressure value but i can't get the point why a tablet bundled with a barometer. probably a marketing trick to make it more expensive. By the way, it can also measure temperature but when compared to ds1820b and DHT11 it's value 3 celsius lower than others. probably surrounding metal case causes that. also pressure resolution not too high as described in other diy sites. anyway can be used in weather alert applications at least.
it's arduino compatible library available in here