The Grove 12 button Capacitive Touch Keypad is built around the ATtiny1616, an AVR® 8-bit processor running at up to 16 MHz. ATtiny1616 is a low-power, high-performance chip integrated QTouch® peripheral touch controller which supports capacitive touch interfaces with proximity sensing and driven shield. With this module, you can easily create an arduino password keypad or a DIY phone keypad.

We made this keypad into a 3x4 form, just like the layout of a mobile phone keyboard. The traditional keypad requires 3 vertical lines and 4 horizontal lines to scan, which will occupy 7 I/O pins of the microcontroller. With the help of ATtiny1616 and Grove connector, only RX and TX two pins are enough for Grove - 12-Channel Capacitive Touch Keypad. You can easily use this module with a microcontroller with a hardware UART interface, or you can use the software UART to read the button input with two normal I/O pins.