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Keypad 4x4 With Buttons Module for Arduino RobotDYN

The 4x4 Keypad Module features 16 tactile push buttons arranged in a matrix layout, making it ideal for numeric input, menu navigation, password entry, and user interface control. The module integrates a resistor ladder network, allowing all keys to be read using a single analog input pin on a microcontroller. Each button produces a distinct voltage level, enabling efficient pin usage while maintaining reliable key detection.

Package Includes:

1 x 4x4 Keypad Module

 

Keypad Module
21.00 AED 21.00 AED (Tax included)

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Features

  • 16 Push Buttons: Standard 4x4 keypad configuration.
  • Analog Output Design: All keys readable via one analog pin.
  • Integrated Resistor Network: Unique voltage per button press.
  • Space-Saving Interface: Minimizes GPIO usage.
  • Protective Keycaps: Transparent covers prevent label wear.
  • Easy Integration: Compatible with Arduino and other microcontrollers.

Specifications

  • Number of Keys: 16 (4x4 matrix)
  • Output Type: Analog voltage levels
  • Operating Voltage: 3.3V – 5V
  • Interface: Single analog signal output
  • Board Type: Resistor ladder keypad module

Pinout

robotdyn-analog-keypad-4x4-1 Managing a 4x4 Analog Keyboard with Arduino

 

robotdyn-analog-keypad-4x4-pinout Managing a 4x4 Analog Keyboard with Arduino

 

  • VCC: Power supply (3.3V – 5V)
  • GND: Ground
  • OUT: Analog signal output

 

Arduino Wiring

  • VCC → 5V (Arduino)
  • GND → GND (Arduino)
  • OUT → Analog Pin (example: A0)

How It Works

The digital keyboard uses an analog input of the Arduino. So we connect the output of the keyboard to the A0 pin of the microcontroller. The keyboard can be powered by the 5V output of the Arduino.

robotdyn-analog-keypad-4x4-principle Managing a 4x4 Analog Keyboard with Arduino

Example Arduino Code

//Constants
#define nbABtn 16

//Parameters
const int abtnPin = A0;
const int valThresh[nbABtn] = {1000, 900, 820, 750, 660, 620, 585, 540, 500, 475, 455, 425, 370, 300, 260, 200};

void setup() {
  //Init Serial USB
  Serial.begin(9600);
  Serial.println(F("Initialize System"));
}

void loop() {
  readAbtn();
}

void readAbtn() { /* function readAbtn */
  //// Read button states from keypad
  int btnId = getABtn();
  if (btnId) {
    Serial.print("Button pressed : "); Serial.println(btnId);
    delay(200);
  }
}

int getABtn() { /* function getABtn */
  //// Read button states from keypad
  int val = analogRead(abtnPin);
  if (val <= 200) {
    return 0;
  } else {
    for (int i = 0; i < 16; i++) {
      if (val > valThresh[i]) return i + 1;
    }
  }
}

Key Detection Logic (Concept)

Each key generates a different analog reading. To decode button presses, compare the measured value against voltage ranges determined experimentally. Exact values may vary slightly depending on supply voltage and resistor tolerances.

Applications

  • Numeric input systems
  • Password / access control
  • Menu navigation interfaces
  • Embedded user controls
  • DIY electronics projects

Tips & Information

  • Analog values may fluctuate slightly — always use tolerance ranges.
  • Supply voltage variations affect readings.
  • Debouncing may be required in fast sampling systems.
  • Test and record voltage levels for accurate key mapping.
  • Ideal for projects requiring minimal pin usage.