This is touch keypad function by measuring the capacitance of 16 electrode points.
This compact inexpensive keypad, can connecting to any Capacitive module. In our catalog you can find 16 Keys Capacitive touch module which base on TTP229 and connecting to microcontroler with I2C bus.
This touch keypad, is both an ideal learning tool for capacitive touch sensing keypads, as well as a fully operational touch keypad that can be easily incorporated in a professional control system or microcontroller application.
Touch pads have numbers from 1 to 16, and can mark with felt-pan.