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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.

asked Aug 22, 2016 at 9:19
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    Tricky at best. CapSense relies on pretty tight time measurement to determine small changes in capacitance. You would be better off using a proper CapSense interface chip. There's plenty to choose from - most of them I2C based. Commented Aug 22, 2016 at 11:32
  • I am new in this field. Can you please refer me any CapSense interface chip. I am using the following touch keypad by waveshare Waveshare Touch Keypad Commented Aug 22, 2016 at 17:03

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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).

answered Aug 22, 2016 at 17:57

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