The 4 x 4 matrix keypad usually is used as input in a project. It has 16 keys in total, which means the same input values. The 4 x 4 Matrix Keypad Module is a non-encoded matrix keypad consisting of 16 keys in parallel. The keys of each row and column are connected through the pins outside – pin R1-R4 as labeled beside control the rows, when L1-L4, the columns.

A 4×4 matrix keypad consisting of microswitch buttons. The module has four holes 3mm (M3) holes for mounting. The pin designations on each PCB are shown on each PCB. Four pins are thus used as an ‘x’ coordinate and the other 4 as a ‘y’ coordinate.
The module is already equipped with a soldered pin-headers.

The keypad consists of pushbutton switches that are arranged in a matrix of 4 rows and 4 columns.  The pushbutton switches are labeled S1 thru S16 and are wired at the intersection of the rows and columns.

Button pushes can be detected using 8 pins on a MCU.  The MCU uses 4 output pins to drive the columns one at a time.  At the same time, it uses 4 input pins to scan the rows at the same time.  This logic can be inverted so it drives the rows and scans the columns.

When no button is pushed, none of the row/column pins are electrically connected.  If a button is pushed, the MCU will see it on an input pin and can determine which button was pushed by which output pin was active when the button push was detected.  For example, if the ‘S8’ button is pressed, there will be a short between the Row 1 and Col 3 pins.

Features:

• This is a simple Key Pad Made by Push Buttons , can be extended to any functionalities.
• These buttons can be placed in different places in robotic applications.
• This design does not need any library and also can be expandable to more buttons.
• This design Does not need any Resistors and also does not use any libraries
• 4×4 Matrix Keyboard Module with 16 buttons
• Small in size and hence Save space
• More convenient to use
• Expanded development application modules for single chip
• With 16 keys and 8 pin

Specification:

• 4 x 4 Matrix Keyboard
• 16 Buttons
• Size: 42x39x11mm

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.

Application:

• DIY MCU keyboard module for learning and development

Package Included:

• 1 x Tactile Switch 4×4 Matrix 16 Keypad Keyboard Module 4×4 Matrix 16 Array Keyboard 16 Button MCU 8Pin 4×4 Micro Switch Tactile Push Button Switch