The Thanksgiving have passed by, and if you’re feeling bored sitting in your house for by doing nothing, then you might want to try something more fun and interesting project!

Well, it’s not too hard to buy a humidity and temperature sensor on the market, but you need to spend over $30 or more for a simple sensor and it definitely didn’t worth at all!

Instead of pulling the money out from your pocket, why don’t you keep the money warm inside your wallet, by simply build your very own digital humidity and temperature sensor?

Since most of the components that being used here are mainly cheap, thus you don’t need to spend too much for constructing a cheap digital humidity and temperature sensor. This is going to be a very compact data logger that using the SHT11 or SHT15 sensor for humidity and temperature.

For your information, the logger will contain 128Kbytes of memory for logging 32768 samples of temperature and humidity or 26214 samples of temperature. The AT90S8535 will be the main heart of this project and it has eight 8-bit analog to digital converters built in.