You can use an external touch controller. For example MPR121 (I2C).
Adafruit 12-Key Capacitive Touch Sensor Breakout - MPR121 or
Sparkfun Touch Shield DEV-10508
You can use an external touch controller. For example MPR121 (I2C).
Adafruit 12-Key Capacitive Touch Sensor Breakout - MPR121 or
Sparkfun Touch Shield DEV-10508