4x4 Matrix Keypad
4x4 matrix keypad with 16 numeric-style buttons, scanned over 8 pins via row/column matrix.
Pinout
- R1
Row 1 output — driven HIGH/LOW by MCU to scan rows
Type · GPIO - R2
Row 2 output
Type · GPIO - R3
Row 3 output
Type · GPIO - R4
Row 4 output
Type · GPIO - C1
Column 1 input — read by MCU; internal pull-up enabled
Type · GPIO - C2
Column 2 input
Type · GPIO - C3
Column 3 input
Type · GPIO - C4
Column 4 input
Type · GPIO
| Pin | Type | Function |
|---|---|---|
| R1 | GPIO | Row 1 output — driven HIGH/LOW by MCU to scan rows |
| R2 | GPIO | Row 2 output |
| R3 | GPIO | Row 3 output |
| R4 | GPIO | Row 4 output |
| C1 | GPIO | Column 1 input — read by MCU; internal pull-up enabled |
| C2 | GPIO | Column 2 input |
| C3 | GPIO | Column 3 input |
| C4 | GPIO | Column 4 input |
Pin details
8 connections- R1
Row 1 output — driven HIGH/LOW by MCU to scan rows
GPIO - R2
Row 2 output
GPIO - R3
Row 3 output
GPIO - R4
Row 4 output
GPIO - C1
Column 1 input — read by MCU; internal pull-up enabled
GPIO - C2
Column 2 input
GPIO - C3
Column 3 input
GPIO - C4
Column 4 input
GPIO
Start wiring
I2C · Analog · USB · 3.3 – 5 V · Breakout
Some modules need I2C or signal pull-ups — check the datasheet.
Keypads
36 other optionsMatrix keypads, analog ADKey boards, I2C keypad controllers, joysticks, and finished USB-HID keyboards are all here. Pin budget and simultaneous-press requirements are the splits that matter.
Adafruit PC Joystick to seesaw I2C Adapter visual previewAdafruit PC Joystick to seesaw I2C Adapter
$3.57
Adafruit Trellis Monochrome Driver PCB for 4x4 Keypad & 3mm LEDs visual previewAdafruit Trellis Monochrome Driver PCB for 4x4 Keypad & 3mm LEDs
Adafruit UNTZtrument 16x8 Grid Controller visual previewAdafruit UNTZtrument 16x8 Grid Controller
$199.99
Bus Pirate v3.6 Universal Serial Interface visual previewBus Pirate v3.6 Universal Serial Interface
CardKB2 Keyboard Unit (ESP32-C61) visual previewCardKB2 Keyboard Unit (ESP32-C61)
Fermion: ADKey Board -10 Keys (Breakout) visual previewFermion: ADKey Board -10 Keys (Breakout)
FS-GT3B visual previewFS-GT3B
Full Size Panel Mount Keyboard with Trackpad visual previewFull Size Panel Mount Keyboard with Trackpad
Gravity: Analog ADKeyboard Module V2 visual previewGravity: Analog ADKeyboard Module V2
Joystick visual previewJoystick
Joystick Module (.NET Gadgeteer Compatible) visual previewJoystick Module (.NET Gadgeteer Compatible)
Kailh Mechanical Key Switch - Clicky Blue - Single Piece visual previewKailh Mechanical Key Switch - Clicky Blue - Single Piece
Related groups
4 groups
12mm Domed Push Button Pack visual previewButtons & switches
Most parts here are simple contacts: press or release, open or closed. A few outliers — rotary switch potentiometer breakouts, NeoPixel potentiometers, wiper plungers — carry separate wiring requirements worth checking before you order.
Input & controls · Buttons & switches · 106 parts
ANO Directional Navigation and Scroll Wheel Rotary Encoder visual previewEncoders
Bare EC11 quadrature encoders, I2C navigation encoders, absolute AS5600 and 8421 encoders, slide and ribbon potentiometers, and digital I2C pots — covering most ways to read angular or linear position.
Input & controls · Rotary encoders · 28 parts
Adafruit 12-Key Capacitive Touch Sensor Breakout - MPR121 [STEMMA QT] visual previewTouch
MPR121, CAP1188, CAP1203 Qwiic slider and AT42QT breakouts are sensor ICs for electrodes you wire yourself. Simple single-pad modules like the TTP223B give you one digital output with no bus required.
Input & controls · Touch sensors · 14 parts
1.75mm PLA (1kg) - Black visual preview3D printing
DFRobot 1.75 mm PLA in 1 kg spools makes up the bulk of the group, in over 15 colors. Specialty options include PVA in both diameters, NinjaFlex flexible filament, Proto-Pasta conductive PLA, and wood-fill. OverLord printer spares and OverLord printers round out the hardware side.
Tools & prototyping · 3D printing · 53 parts