Circuit Diagram 4x4 Matrix Keypad. The idea involves using a microcontroller to send required messages to the given mobile number through gsm communication. By margaret byrd february 5 2018.
The proposed project has pretty minimalistic hardware design. If we see the port there are 8 pins first 4 from left to right are x1 x2 x3 and x4 are the rows and last 4 from left to right are y1 y2 y3 y4 are four columns. The same logic applies to any matrix keypad of order nxn.
Like in our case we are using 4x4 matrix keypad in which there are 4 push buttons in each of four rows.
Beneath each key is a special membrane switch. If we see the port there are 8 pins first 4 from left to right are x1 x2 x3 and x4 are the rows and last 4 from left to right are y1 y2 y3 y4 are four columns. For example if c1 c2 c3 c4 0111 this means that a key in the c1 column has been pressed. The keypad is usually made of plastic materials and is relatively cheap compared to touchscreen displays.