[GerardvanA]

Hi,
Thanks for your reply.
I have got the AVR Boards v 1.6.21 (compiling for a Nano using the Old bootloader (tried the others but no difference).
It was great to have all the libraries with the code, however I did have to get some that the IDE indicated were missing. I can't recall details anymore on which ones, so went back to the supplied Libraries (deleted my folder). To make sure I'm using that library my IDE skethbook location is set to:

/home/gerard/Arduino/WeatherDuino/WeatherDuino_Pro2_Compact

So compiling the TX firmware gives this error:
=======================================
WeatherDuino_Pro2_Universal_TX_v7.0_b003:56:72: fatal error: HTU21D.h: No such file or directory
 #include <HTU21D.h>                // library for HTU21 Temp/Hum Sensor
                                                                        ^
compilation terminated.
exit status 1
HTU21D.h: No such file or directory
==============================================
I installed that library, and then the compile gets to the SHT2x problem: (note this is different in the upper/lowercase of some statements, as I started again with the supplied code in the rar file. I'm running a Linux system and because that tends to be more case sensitive, I'd changed the case of 'GetTemperature' to getTemperature' as it's written like that in the library file, to see if that was the problem)
==============================================================
/home/gerard/Arduino/WeatherDuino/WeatherDuino_Pro2_Compact/software/TX software/WeatherDuino_Pro2_Universal_TX_v7.0_b003/Routines.ino: In function 'void read_SHT21()':
Routines:10:22: error: expected primary-expression before '.' token
       T_ExtS0 = SHT2x.GetTemperature() * 100.0;
                      ^
Routines:11:22: error: expected primary-expression before '.' token
       H_ExtS0 = SHT2x.GetHumidity() * 100.0;      
                      ^
exit status 1
expected primary-expression before '.' token
============================================================

Any further clues as what I can have set wrong?
Thanks, Gerard