user25944: i want to use multiple capacitive touch keypads with arduino uno but number of IO ports are not enough. So I decided to use MSP23S17 port extender. Now i have to find some methods to sense the touch keypad without using its library. Can anyone tell me if there is any way to do the task.

user19457: Here's one: Microchip mtch6102, though it might be a little more complex than you're looking for.  All the others I found with a quick search were surface mount or single button controllers.  You might be able to multiplex a single button controller like the Atmel AT42QT1011, but I don't know what the settling or reset times are.  It may take to long to change pads, reset the chip, then wait for settling/calibration time (if any).

25944: <p>i want to use multiple capacitive touch keypads with arduino uno but number of IO ports are not enough. So I decided to use MSP23S17 port extender. Now i have to find some methods to sense the touch keypad without using its library. Can anyone tell me if there is any way to do the task.</p>
 19457: <p>Here's one: Microchip mtch6102, though it might be a little more complex than you're looking for.  All the others I found with a quick search were surface mount or single button controllers.  You might be able to multiplex a single button controller like the Atmel AT42QT1011, but I don't know what the settling or reset times are.  It may take to long to change pads, reset the chip, then wait for settling/calibration time (if any).</p>
