SHT11 - RaresPlescan/daisypi GitHub Wiki
SHT11 is a digital temperature sensor 
It has a nice sensitivity and accuracy and for us was the perfect choice because of the price / features ratio.
Ratings :
Supply voltage : 2.4 V to 5.5 V
Temperature : -40 .. +123 C, resolution 0.01 C, accuracy +- 0.4 C
Humidity ( RH ) : 0 .. 100 %, resolution 0.05 %, accuracy +- 4.5 %
Output : digital, proprietary protocol similar to I2C
Producer's page and documentation :
The C code is taken from this site : http://www.john.geek.nz/ and some modifications were made in order to make its output AWK friendly .
Besides the regular commands for reading temperature and relative humidity and a formula for computing analytical dew point, it features an interesting "heating" command aimed to dry the sensor's reading chamber and provide a feedback check for the temperature ( it is not implemented yet in the current version of the C code.
Our modified code is here : SHT11 source code for Daisy Pi
The executable will output in one line the following values:
-temperature
-relative humidity
-dew point