robtillaart
sorry should i replace my
if (isnan(t) || isnan(h)) {
with
if t == NaN and h == NaN
??
String ttd =dtostrf(t,5,2,buffer1);
This casts a float or double to a string. I have no idea if its valid but it works 
I thought its a power problem too, but the LCD should use less than what arduino itself can supply, but i added a external power supply (5v,3A) but got exactly the same results.
hehe on the comment and code difference, the comment is to remind myself how it works but i changed the actual pins and code for some reason only myself at 2am in the morning knew!!
at the moment the temp difference to a thermometer is about 1 degC but i still cant use the LCD with the sensor or the sensor gives false values 