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The 4x3 Matrix Array Flexible Membrane Keypad is a lightweight, low-cost user interface module engineered for projects that demand numeric input, PIN validation, or menu selection. Organized into 4 Rows and 3 Columns (12 keys total: numbers 0 to 9, plus the asterisk * and hash # symbols), it mimics standard telephone keypad ergonomics for effortless user operation.

Built with flexible, multi-layered printed circuit traces underneath a protective overlay, each key offers a crisp tactile bump when pressed. The back panel includes a pre-applied high-tack 3M adhesive backing, enabling flush surface-mounting on plastic project boxes, acrylic panels, or aluminum enclosures. Its 7-conductor flexible ribbon cable ends in a standard 2.54mm pitch female header, allowing quick connection using standard male-to-male or male-to-female jumper wires.

Key Features and Benefits

• 12-Key Standard Telephone Layout: Contains numbers 0 through 9 along with * and # keys for PIN codes and menu control.

• Matrix Circuit Organization: Reduces microcontroller I/O pin consumption down to just 7 digital pins (4 rows + 3 columns) instead of 12 separate inputs.

• Ultra-Thin & Flexible: Low-profile membrane structure allows clean, flush mounting without wasting space inside equipment housings.

• 3M Peel-and-Stick Adhesive Backing: Allows immediate, tool-free installation on any flat surface.

• Standard 2.54mm Interface: Plugs directly into breadboards, male pin headers, and standard development boards.

Technical Specifications

Pinout & Wiring Guide

The keypad exposes 7 pins on its flexible ribbon cable corresponding to 4 Rows and 3 Columns:

7-Pin Header Layout (Left to Right):

• Pin 1: Row 1 (Keys: 1, 2, 3)

• Pin 2: Row 2 (Keys: 4, 5, 6)

• Pin 3: Row 3 (Keys: 7, 8, 9)

• Pin 4: Row 4 (Keys: *, 0, #)

• Pin 5: Column 1 (Keys: 1, 4, 7, *)

• Pin 6: Column 2 (Keys: 2, 5, 8, 0)

• Pin 7: Column 3 (Keys: 3, 6, 9, #)

Arduino Quick-Start Code Example

#include <Keypad.h>

const byte ROWS = 4; // 4 Rows
const byte COLS = 3; // 3 Columns

char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};

// Connect to Arduino Digital Pins 2 through 8
byte rowPins[ROWS] = {8, 7, 6, 5}; // Connect to Row 1, Row 2, Row 3, Row 4
byte colPins[COLS] = {4, 3, 2};    // Connect to Col 1, Col 2, Col 3

Keypad customKeypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  Serial.begin(9600);
  Serial.println("4x3 Keypad Testing Initialized...");
}

void loop() {
  char customKey = customKeypad.getKey();
  
  if (customKey) {
    Serial.print("Pressed Key: ");
    Serial.println(customKey);
  }
}

Applications

• Door Access & PIN Systems: Build custom electronic door locks requiring multi-digit security passcodes.

• Calculator & Measuring Tools: Enter target values for digital scales, timers, and benchtop counters.

• Vending & Dispensing Machines: Select item numbers for automated inventory or drink dispensers.

• Industrial Parameter Entry: Input setpoints, speed limits, and operation modes for motor drivers and PLCs.

Package Includes

• 1 x 4x3 Matrix Array Flexible Membrane Keypad (12 Keys)

Shipping & Delivery

• Free shipping on orders above ₹999 across India

• Dispatched within 1-3 business days

• Expected delivery: 3-7 business days depending on location

• Secure packaging to ensure safe transit of electronic components