New updated library using urban's code. works fine.
the example qTouchADC_urban... is working fine now.
To do: try to make it compatible accros different boards. Arduino Uno, Micro/leonardo, Attiny. how to access this different port and deal with the weird numbering of the ADC in the ADMUX of the attiny?
see some inspiration of nice code: http://tuomasnylund.fi/drupal6/content/capacitive-touch-sensing-avr-and-single-adc-pin