OK, first, if you touch the hygro, it needs to be cleaned with alcohol (no, not beer ) and if your readings are off, it's because you probably had a low wattage (low wattage does not mean cheap) soldering iron and cooked something.

Most circuit soldering is done with higher wattage's because you have very little surface touch time. This means that after a second or so, the heat will start to do microscopic damage to the circuits and the sensors. Radio Shack sells an item that is made off aluminum and looks like a little clothes pin. It is called a heat sync and will prevent the heat from reaching the sensor. I did not have this item at my disposal when I undertook this project though. But if you have not done a lot of soldering, it may help a little bit. They also have the second pair of hands you always wish you had when doing wierd projects. It's the goofy looking cloths pin clamp and magnifying glass thingy they have in the soldering section for $20.

I would like to see some pics of the ones you guys have done. Maybe I will learn something new to do with my next one.......