Membrane 3×4 Matrix Keypad
Membrane 3×4 Matrix Keypad
Membrane 3×4 Matrix Keypad
Membrane 3×4 Matrix Keypad
Membrane 3×4 Matrix Keypad
Membrane 3×4 Matrix Keypad

Membrane 3x4 Matrix Keypad

Keypads
SWK220
Part.No: 0260
€2.50
In Stock
Immediate Dispatch
Membrane 3x4 Matrix Keypad with 12 keys arranged in a telephone-style grid. Passive matrix interface requiring only 7 GPIO pins (4 rows + 3 columns). Features self-adhesive backing, Dupont 2.54mm connector, and 1 million cycle life expectancy. Compatible with Arduino, ESP32, and most microcontrollers.

 

The Membrane 3×4 Matrix Keypad is a compact, thin, and flexible 12-button input device ideal for adding user input to embedded projects. Arranged in a classic telephone-style 3-column × 4-row grid, this fully passive keypad requires no power supply of its own — it operates entirely via GPIO scanning, needing just 7 microcontroller pins (3 columns + 4 rows) to read all 12 keys. Its self-adhesive backing makes it easy to mount on enclosures, project boxes, or panels, while the ultra-thin 0.8mm profile ensures a clean, professional look.

Key Features

  • 12-Key Matrix Layout (3×4): Telephone-style grid (digits 0–9, *, #) — covers the most common input scenarios for embedded UIs
  • Passive Matrix Interface: No VCC or GND power pins required — reduces wiring complexity and GPIO usage vs. individual button arrays
  • 7-Pin Dupont Connector (2.54mm pitch): Standard 0.1" spacing — plugs directly into a breadboard or Arduino header without adapters
  • Self-Adhesive Backing: Peel-and-stick mounting — attach permanently to any flat surface for clean project integration
  • Ultra-Thin Membrane Construction (0.8mm): Flexible, lightweight design — fits in space-constrained enclosures where mechanical buttons cannot
  • 1,000,000 Cycle Life Expectancy: Rated for one million key presses — reliable for long-term deployed projects
  • Contact Bounce ≤ 5ms: Low bounce time — simplifies debounce logic in firmware

Pinout & Wiring

The keypad outputs 7 pins via its Dupont connector. The standard row/column assignment (from pin 1 to pin 7) for a 3×4 keypad is as follows:

PinSymbolDescription
1R1Row 1 (top row: 1, 2, 3)
2R2Row 2 (4, 5, 6)
3R3Row 3 (7, 8, 9)
4R4Row 4 (bottom row: *, 0, #)
5C1Column 1 (left: 1, 4, 7, *)
6C2Column 2 (center: 2, 5, 8, 0)
7C3Column 3 (right: 3, 6, 9, #)

Wiring note: Connect the 7 pins to any 7 available digital GPIO pins on your microcontroller. On Arduino, use the Keypad library (by Mark Stanley) — define your row and column pin arrays in code and the library handles all scanning and debounce logic automatically.

Compatibility

  • Arduino UNO / Nano / Mega: Full compatibility — use 7 digital GPIO pins with the standard Arduino Keypad library
  • ESP32 / ESP8266: Compatible — use 3.3V-tolerant GPIO pins; passive device works at any logic level
  • Raspberry Pi (via GPIO): Compatible with Python keypad or RPi.GPIO libraries
  • STM32 / ATmega / Any microcontroller with 7 GPIO pins: Compatible — fully passive, logic-level independent

Typical Applications

  • PIN entry and access control systems (door locks, safes)
  • Menu navigation in Arduino LCD display projects
  • Numeric input for DIY calculators or data loggers
  • Password-protected relay or alarm systems
  • Interactive kiosk or vending machine prototypes
  • Educational embedded systems labs and electronics courses

Technical Specifications

ParameterValue
Interface / ProtocolPassive matrix (4 rows × 3 columns), direct GPIO scanning
Number of Keys12 (3×4 grid)
ConnectorDupont 7-pin, 2.54mm (0.1") pitch
Max Circuit Voltage35V DC
Max Circuit Current100 mA
Insulation Resistance100 MΩ @ 100V
Dielectric Withstand250 Vrms (60Hz, 1 min)
Contact Bounce≤ 5 ms
Life Expectancy1,000,000 closures
Operating Temperature-20°C to +40°C
Mount StyleSelf-adhesive backing
Pad Dimensions69.2 × 76.9 × 0.8 mm
Cable Length~86 mm (including connector)

FAQ

Q: Do I need pull-up or pull-down resistors to use this keypad?
A: When using the Arduino Keypad library, internal pull-up resistors are enabled automatically via INPUT_PULLUP. No external resistors are required — the library handles this in software.

Q: Can I detect multiple simultaneous key presses (rollover)?
A: Standard 4×3 matrix scanning without diodes does not reliably support multi-key (n-key rollover) detection. For single key input (which covers the vast majority of use cases), it works perfectly.

Package Contents: 1 × Membrane 3×4 Matrix Keypad with pre-attached Dupont 7-pin connector cable (~86mm)

⚠️ Note: This is a fully passive device — there are no VCC or GND power pins. Do not apply voltage directly across the connector pins without a current-limiting circuit.

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