MPR121 Touch Shield 12 keys 12 Channels 5V 3.3V

product description
MPR121 Capacitive Keyboard The MPR121 and 12 touch panels provide you with a simple "keyboard" with I2C output. The board also has four mounting holes that can be used as an input instead of the traditional buttons. Check the sample code below to read the keyboard. Note: This keyboard outputs 3.3V logic. If you are using a board that accepts only 5V logic, you will encounter problems. You will need to use a logic level shifter or board that accepts 3.3V logic.