The TK-3x4CL capacitive keypad uses the AT42QT2120 integrated circuit and 12 touch sensitive pads to provide a simple 'keypad' with an I2C communication. This keypad functions by measuring the capacitance of twelve electrode points. When an object comes close to the electrode connector, the measured capacitance changes. The AT42QT2120 signals the microcontroller that touch is detected.

The TK-3x4CL uses the IS32FL3740 integrated circuit to indicate a key pressed by turning on the corresponding LED. The IS32FL3740 uses an I2C communication.

This keypad accepts 3.3V or 5V VCC.

The custom graphic overlay can be provided upon request.

Documents:

TK-3x4CL Schematic (pdf - 390 KB)

TK-3x4CL Sample Code (ino - 3.63 KB)