Earthquake Detector Alarm using Arduino and Accelerometer

Earthquakes rank among the most devastating natural disasters, capable of leveling cities, crippling infrastructure, and claiming lives within moments. While major seismic events are rare, their unpredictable nature underscores the urgent need for early detection systems. Even a few seconds of advance warning can save lives by enabling people to seek shelter, shut off gas lines, or halt critical machinery. In this article, we’ll explore how to construct a prototype earthquake detector alarm using accessible components—an Arduino microcontroller and an accelerometer—to demonstrate the fundamental principles of vibration sensing and real-time hazard alert systems.

Why Early Detection Matters

Modern seismic networks rely on advanced sensors and algorithms to predict earthquakes, but these systems require significant infrastructure and expertise. This project, while simplified, serves as an educational gateway into understanding how vibrations are measured and translated into actionable alerts. By working with an accelerometer (a device that detects changes in motion or force), we can simulate how professional systems identify sudden ground movements characteristic of seismic activity.

How the Prototype Works

1. The Accelerometer: This sensor measures acceleration forces, including subtle vibrations or abrupt shakes. When mounted on a stable surface, it detects deviations caused by tremors.
2. The Arduino: Acting as the brain of the system, the Arduino processes the accelerometer’s data in real time. By programming thresholds for vibration intensity, the microcontroller can distinguish between everyday movements (e.g., a door slamming) and potential earthquake-like patterns.
3. The Alert System: When a significant vibration is detected, the Arduino triggers an alarm—such as a buzzer, LED.

Dive into the tutorial below to start coding, wiring, and testing your own earthquake detection system. Who knows? Your prototype might just inspire the next breakthrough in emergency response innovation.

Components Required

1. Arduino Uno or Nano (or compatible board)
2. ADXL345 Accelerometer Module 
3. Buzzer (active or passive) (for alarms)
4. Ssd1306 OLED display module
5. LED (with 220Ω resistor)
6. Breadboard & Jumper Wires
7. USB Cable (for power and programming).

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Understanding the Accelerometer

The accelerometer measures acceleration forces (in g-forces) on the X, Y, and Z axes. For earthquake detection, we will monitor the acceleration values and determine if they exceed a predefined threshold, indicating seismic activity, Arduino triggers an audible alarm (buzzer) and visual alert (LED).

Choosing the Accelerometer

For this project, we will use the ADXL345 accelerometer, which communicates via I2C. The MPU6050 is another popular choice, but for simplicity, we will focus on the ADXL345.

ADXL345 Triple Axis Accelerometer Board is a compact, low-power 3-axis accelerometer with a 13-bit resolution, measuring ±2g to ±16g. It provides a 16-bit two’s complement digital output via SPI or I2C.

Ideal for mobile devices, it detects static tilt and dynamic motion with a high 4 mg/LSB resolution, enabling inclination changes under 1°. Special features include activity/inactivity detection, tap sensing, and free-fall detection, with interrupt mapping. A 32-level FIFO buffer reduces processor load, while low-power modes optimize motion-based power management.

Circuit Diagram

Source code for Earthquake Detection Alarm

After connecting accordingly, its time to upload the code using Arduino IDE. If you are new to Arduino refer our detailed tutorial: How to Install Arduino IDE on Your PC

Libraries Required

To interface with the ADXL345, we will use the Adafruit_ADXL345 library. You can install it via the Arduino Library Manager.

Arduino Code:

//Earthquake Detection Alarm using Arduino by Circuitschools.com
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define BUZZER_PIN 2
#define THRESHOLD 1.5 // Adjust this threshold based on testing

Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified();
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(9600);
  pinMode(BUZZER_PIN, OUTPUT);
  
  if (!accel.begin()) {
    Serial.println("No ADXL345 detected. Check your connections.");
    while (1);
  }
  
  accel.setRange(ADXL345_RANGE_16_G);
  Serial.println("ADXL345 is ready.");

  // Initialize the OLED display
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Earthquake Detector");
  display.display();
}

void loop() {
  sensors_event_t event; 
  accel.getEvent(&event);
  
  // Calculate the magnitude of the acceleration vector
  float magnitude = sqrt(event.acceleration.x * event.acceleration.x +
                         event.acceleration.y * event.acceleration.y +
                         event.acceleration.z * event.acceleration.z);
  
  Serial.print("Magnitude: ");
  Serial.println(magnitude);
  
  // Update OLED display
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("X: "); display.print(event.acceleration.x);
  display.print(" m/s^2");
  display.setCursor(0, 10);
  display.print("Y: "); display.print(event.acceleration.y);
  display.print(" m/s^2");
  display.setCursor(0, 20);
  display.print("Z: "); display.print(event.acceleration.z);
  display.print(" m/s^2");
  display.setCursor(0, 30);
  display.print("MAG: "); display.print(magnitude);
  display.print(" m/s^2");
  
  // Check if the magnitude exceeds the threshold
  if (magnitude > THRESHOLD) {
    Serial.println("Earthquake detected! Triggering alarm.");
    digitalWrite(BUZZER_PIN, HIGH); // Turn on the buzzer
    display.setCursor(0, 50);
    display.println("Earthquake Detected!");
    display.display();
    delay(1000); // Alarm duration
    digitalWrite(BUZZER_PIN, LOW); // Turn off the buzzer
  } else {
    display.setCursor(0, 50);
    display.println("No Earthquake.");
  }
  
  display.display();
  delay(500); // Adjust the delay as needed
}

Code Explanation

This code sets up an earthquake detector using an accelerometer (ADXL345) and an OLED display (SSD1306) with Arduino. Here’s a concise breakdown:

1. Hardware Setup:
   • ADXL345 accelerometer measures 3-axis motion.
   • OLED display shows real-time acceleration data.
   • Buzzer (pin 2) triggers an alarm when shaking is detected.
2. Functionality:
   • Calculates total acceleration magnitude using sqrt(x² + y² + z²).
   • Threshold Check: If magnitude exceeds 1.5 m/s² (adjustable), it:
     • Activates the buzzer.
     • Shows “Earthquake Detected!” on the OLED.
   • Displays live X/Y/Z acceleration values and magnitude on the OLED.
   • Serial Monitor logs magnitude for debugging.
3. Loop Timing:
   • Updates readings every 500ms to balance responsiveness and stability.

Serial Monitor Output

When you run the code and open the Serial Monitor in the Arduino IDE, you will see output similar to the following:

ADXL345 is ready. 

Magnitude: 1.02 
Magnitude: 1.12
Magnitude: 1.08
Magnitude: 1.75 
Earthquake detected! Triggering alarm. 
Magnitude: 2.30 
Magnitude: 1.90
Magnitude: 1.10 
Magnitude: 1.05

Explanation of the Output:

• Normal State: Magnitude values stay below 1.5 m/s² (e.g., 1.02, 1.12).
• Earthquake Detected: When magnitude exceeds 1.5 (e.g., 1.75), the buzzer activates, and the message appears.
• Alarm Duration: The buzzer stays on for 1 second (delay(1000)).
• Updates Every 500ms: New magnitude values print every 0.5 seconds (due to delay(500)).

OLED Display Output

The OLED display will show the following information in a structured format. The display will update every half second, showing the current acceleration values and the magnitude. Here’s how it would look:

Educational Value and Limitations

This project is designed to illustrate core concepts in sensor technology, data analysis, and emergency response systems. It encourages hands-on learning in coding, circuit design, and problem-solving. However, it’s crucial to note that this prototype lacks the sensitivity, calibration, and redundancy of professional seismic equipment. It should not be relied upon for life-saving warnings but rather as a foundational tool to spark interest in engineering, disaster preparedness, or IoT applications.

Expanding the Project

For those eager to enhance the system, consider integrating:

• GPS modules to log tremor locations.
• Cloud connectivity to broadcast alerts to multiple devices.
• Machine learning models to improve pattern recognition and reduce false positives.

A Call to Innovate

By building this prototype, you’ll gain practical insights into the challenges of disaster detection technology—and the ingenuity required to address them. Whether you’re a student, hobbyist, or educator, this project bridges theory and practice, empowering you to contribute to a safer, more resilient future.

Note: Always pair DIY safety systems with certified alerts from local authorities. This project is a learning exercise, not a replacement for professional seismic monitoring.