Membrane 4x5 Matrix Keypad
Membrane 4x5 Matrix Keypad
Membrane 4x5 Matrix Keypad
Membrane 4x5 Matrix Keypad

Membrane 4x5 Matrix Keypad

Keypads
SWK250
Part.No: 0262
€3.00
In Stock
Immediate Dispatch
Membrane 4x5 Matrix Keypad with 20 keys arranged in a 4-column × 5-row grid. Ultra-slim design with adhesive backing, 9-pin output, and 3.3V–5V operating voltage — ideal for Arduino, ESP32, and breadboard prototyping.

 

The Membrane 4×5 Matrix Keypad is a compact, ultra-thin 20-key input device designed for microcontroller projects, prototyping, and embedded systems. With its 9-pin ribbon connector and passive matrix scanning interface, it gives you full access to all 20 keys using only 9 GPIO pins — 4 rows and 5 columns. The adhesive backing lets you mount it permanently to any flat surface, making it a clean and practical addition to custom enclosures, control panels, or breadboard setups.

Κύρια Χαρακτηριστικά / Key Features

  • 20-Key Matrix Layout (4 rows × 5 columns): Full 20-button input with only 9 GPIO pins required — efficient pin usage for any microcontroller project.
  • 3.3V – 5V Operating Voltage: Compatible with both 3.3V (ESP32, Raspberry Pi) and 5V (Arduino UNO, Mega) logic levels — no level shifter needed in most cases.
  • Passive Matrix Interface (Direct GPIO Scanning): No I2C, SPI, or UART required — works with standard digital I/O pins and simple scanning code using libraries like Keypad.h.
  • Ultra-Slim Membrane Construction: The thin, flexible membrane design allows flush mounting on surfaces — ideal for custom project enclosures.
  • Adhesive Backing: Peel-and-stick mounting — no screws, brackets, or glue needed for installation.
  • 9-Pin Ribbon Connector, 18 cm Cable: Long enough for flexible placement inside a project box or on a breadboard.
  • Low Contact Resistance (0.5–10 Ω): Ensures reliable keypress detection even at low drive currents.

Pinout & Wiring

The 9-pin ribbon cable maps to 4 row lines and 5 column lines. The matrix scanning principle works as follows: set one row LOW at a time, then read each column pin — a LOW reading on a column indicates a pressed key at that row/column intersection.

PinSymbolDescription
1R1Row 1 (top row)
2R2Row 2
3R3Row 3
4R4Row 4 (bottom row)
5C1Column 1 (leftmost)
6C2Column 2
7C3Column 3
8C4Column 4
9C5Column 5 (rightmost)

Wiring note: Connect the 4 row pins to 4 digital output pins and the 5 column pins to 5 digital input pins (with internal pull-ups enabled) on your microcontroller. No external resistors required when using INPUT_PULLUP mode on Arduino.

Compatibility

  • Arduino UNO / Nano / Mega: 5V GPIO — direct connection, use the Keypad.h library for easy integration.
  • ESP32 / ESP8266: 3.3V GPIO — fully compatible, use INPUT_PULLUP on column pins.
  • Raspberry Pi (any model): 3.3V GPIO — compatible with Python RPi.GPIO or gpiozero matrix scanning.
  • STM32 / Teensy / ATmega-based boards: Compatible with any platform supporting direct GPIO digital scanning.

Typical Applications

  • PIN entry and password protection systems on Arduino projects
  • Menu navigation for LCD/OLED display interfaces
  • Custom control panels for robotics and automation
  • Numeric data entry for data loggers and embedded instruments
  • DIY alarm system keypads and access control prototypes
  • Educational microcontroller labs and university projects

Technical Specifications

ParameterValue
InterfaceDirect GPIO Matrix Scanning (4 rows × 5 columns)
Number of Keys20
Operating Voltage3.3V – 5V DC
Max Voltage (circuit)50V DC
Max Current100 mA
Contact Resistance0.5 – 10 Ω
Insulation Resistance≥ 100 MΩ @ 100V DC
Dielectric Withstand250V RMS (50–60 Hz, 1 min)
Contact Bounce≤ 5–6 ms
Operating Temperature−20°C to +60°C
Storage Temperature+15°C to +35°C
Storage Humidity70% – 90%
Panel Size75 × 85 mm
Cable Length18 cm
Output Connector9-pin ribbon cable
MountingAdhesive backing (peel-and-stick)

Frequently Asked Questions

Q: Do I need external pull-up or pull-down resistors for this keypad?
A: No — when using Arduino, simply configure the column pins as INPUT_PULLUP in your sketch. The internal pull-up resistors handle the logic correctly, and the Keypad.h library does this automatically.

Q: Can I use this keypad with an ESP32 or Raspberry Pi?
A: Yes. The keypad operates at 3.3V–5V, making it directly compatible with 3.3V GPIO platforms like the ESP32 and Raspberry Pi without any level-shifting circuitry.

Package Contents: 1 × Membrane 4×5 Matrix Keypad (20 keys) with 9-pin ribbon cable (18 cm) and adhesive backing pre-applied.

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