hi, I tried to make your code work but no chance 
I am using a 3.3M resistor and I don't have a clue :-/
Here is a picture:
The white cable has a piece of copper ( 4x3cm ) at the other end.
I am new to arduino so you might find me quite silly. I was planning on using a qt but if your technique works it's better.
Thank you for your time and contribution to arduino.