Description

The Keypad 4×3 Self-Adhesive 12 Key is a compact, reliable, and easy-to-use input interface designed for a wide range of electronics and microcontroller projects. This flexible membrane keypad features 12 tactile push buttons arranged in a 4-row by 3-column matrix, making it ideal for applications that require numeric or simple command inputs such as password entry, menu navigation, control panels, and data entry systems.

Constructed with a durable polyester film, the keypad ensures long-lasting performance even with frequent use. The keys are printed with clear, wear-resistant characters (0–9, *, and #), which provide a familiar telephone-style layout. This makes it perfect for user interfaces in embedded systems, access control projects, and Arduino-based devices.

One of the main advantages of this keypad is its self-adhesive backing, which allows for easy and secure installation on any smooth surface. You can simply peel off the protective layer and stick it directly onto your project enclosure, robot panel, or control board without needing screws or brackets. This not only saves assembly time but also ensures a neat and professional finish for your design.

Technical Specifications:

• Type: 4×3 Matrix Membrane Keypad

• Number of Keys: 12

• Layout: 4 Rows × 3 Columns

• Keys: 0–9, *, #

• Operating Voltage: 3V to 5V (compatible with 3.3V and 5V logic systems)

• Interface: 7-pin connection (R1–R4 and C1–C3)

• Key Operating Force: 150–200 g

• Life Expectancy: 1,000,000 presses per key

• Material: Polyester film with conductive carbon contacts

• Dimensions: Approx. 70mm × 77mm × 1mm

• Cable Length: Around 85mm

• Connector Type: 7-pin female header (2.54mm pitch)

• Adhesive Type: High-quality 3M self-adhesive backing

Features and Benefits:

1. Simple Matrix Interface:
   The keypad uses a 4×3 matrix connection, meaning it only requires 7 I/O pins on your microcontroller (4 for rows and 3 for columns). This efficient design reduces wiring complexity and allows easy interfacing with boards like Arduino, ESP32, Raspberry Pi, STM32, and PIC microcontrollers.

2. Self-Adhesive Design:
   The integrated 3M adhesive backing makes mounting the keypad effortless. You can attach it to plastic, metal, or acrylic surfaces quickly without additional hardware.

3. Durable Construction:
   Made from high-quality membrane material, this keypad is resistant to dust and moisture, making it suitable for use in educational, industrial, and DIY applications.

4. Tactile Feedback:
   Each button provides a satisfying tactile response when pressed, allowing users to know that their input has been registered.

5. Versatile Applications:
   This keypad can be used in multiple projects including:

   • Security systems and door locks

   • Vending machines and kiosks

   • Industrial control panels

   • Access control systems

   • Arduino password entry projects

   • DIY electronics and robotics interfaces

6. Compatible with Multiple Platforms:
   Whether you’re using an Arduino UNO, Mega, Raspberry Pi, or ESP8266, this keypad can be easily interfaced using standard libraries such as the Keypad.h library in Arduino IDE.

Example Application:

In an Arduino-based door lock project, the 4×3 keypad can be used to enter a numeric password. The input digits are scanned using the matrix configuration, and when the correct code is entered, the Arduino triggers a relay or servo motor to unlock the door. The * and # keys can be used as special function keys (for example, * to reset input and # to confirm).

How It Works:

The matrix layout allows the microcontroller to detect which key is pressed by scanning the row and column connections. When a button is pressed, it connects one row to one column, and the controller identifies the intersection point to determine the specific key. This approach is efficient and minimizes pin usage while allowing accurate key detection.

Why Choose the 4×3 Keypad:

If your project requires numeric entry without the need for additional function keys (like in a 4×4 keypad), the 4×3 version is more compact and cost-effective. It saves board space and fits easily on smaller enclosures while maintaining reliable functionality.

Applications:

• Digital code locks

• Home automation control panels

• Calculator and numeric input projects

• Menu navigation in embedded systems

• Robotic control interfaces

• DIY alarm systems

Summary:

The Keypad 4×3 Self-Adhesive 12 Key is the perfect solution for adding a professional-grade numeric input interface to your electronics project. With its durable design, easy installation, and broad compatibility, it’s a must-have component for any hobbyist, engineer, or student working on interactive electronic systems.

Whether you’re building a prototype or a finished product, this keypad offers reliability, simplicity, and ease of integration—all in a compact, affordable package.