4×4 Matrix 16 Keypad Keyboard Module 16 Button MCU

Typically, a project’s 4 × 4 matrix keypad is used for input. It takes the same input values because there are 16 keys in total. With 16 parallel keys, the 4 x 4 Matrix Keypad Module is a non-encoded matrix keypad. The pins outside, designated R1–R4, are where the keys of each row and column are attached. Pins L1–L4 control the columns, while pins R1–R4 control the rows.

A 4×4 matrix keypad with buttons for microswitches. There are four 3mm (M3) mounting holes on the module. Every PCB has pin designations that are displayed on the board. Hence, four pins are utilised as the “x” coordinate and the remaining four as the “y” coordinate.
There are already soldered pin-headers on the module.

How it Works:

First test whether any key is pressed down. Connect power to rows, so they are High level. Then set all the rows R1-R4 as Low and then detect the status of the columns. Any column of Low indicates there is key pressing and that the key is among the 4 keys of the column. If all columns are High, it means no key is pressed down. Next, locate the key. Since the column in which the pressed key lies is identified, knowing the line would finalize the testing. Thus, set the rows as Low in turns until any is unveiled accordingly – other rows will still be High.
Now the row can be identified. Detect the status of each column in turns. The column tested Low is the one intersecting with the line – their cross point is just the key pressed.

Features: 

• 16-button 4×4 matrix keyboard module
• Tiny in size, so Conserve space; easier to utilise
• Enhanced application modules for development on a single chip
• 16 keys and 8 pins