The MPR121 IC is a great way to build simple capacitive touch interfaces,and now it is easier to integrate into your Arduino projects touch module. Touch module has 9 capacitive touch panels, with the head, and the remaining 3 electrode connections. In addition,at the back of the board we added two new analog buttons, with this module, you can have a total of 12 touch sensitive keys and two analog buttons. On-board logic level converter allows it to work with 5V and 3.3V Arduino board. note：MPR121 IC working voltage of 3.3V,the power to the module,do not mistake the input voltage.