linear humidity coefficients out of date for newer sensors ( after 2008 ? )

[cenau]

Sensors after v3 use a new set of more 'optimised' coefficients. The lib only uses the old ones.

New coefficients

C1 = -2.0468;
C2 = 0.0367;
C3 = -0.0000015955;

relevant lines 82 to 84 in SHT1x.cpp

Most recent datasheet
http://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/Humidity/Sensirion_Humidity_SHT1x_Datasheet_V5.pdf

Older datasheet explaining the change
http://courses.cs.tau.ac.il/embedded/docs/TelosB/SHT11.pdf

[LittleHelper00]

This optimisation of the coefficients instroduced in Dec 2011 is valid for both Sensirion families SHT1x (SHT10, SHT11, SHT15) and SHT7x (SHT71, SHT75).
The lib needs updating with the new values.

Thanks
Giulio
https://twitter.com/giuliotamberi