This is an improved version provided by
Jarda Pajskr from Czech Republic.

He has designed a correction function which uses
a graph with four lines for better approximation.
Now the accurancy is better than 0.4%  humidity in most cases.
He approximated the natural logaritmus by 8 lines. He changed some
constants in the formula for calculating the dew point. Now 
the accurancy for temperature less than 30'C is +- 0.2'C in 
most cases and for temperature up to 100'C is +- 1'C.

The code is a bit larger than the original tuxgraphics code.

Some comments in the code are now in Czech. We don't
speak Czech but if you understand it then 
please feel free to clean it up and send us
the code with English comments.

The code is un-tested and "as is". It is what Jarda Pajskr provided.
You can reach Jarda via jarda.pajskr  at  tiscali.cz


Regards
 Guido