How to retain the on state of the LED and buzzer if the sensor is triggered?

Question

I'm working on a project which is likely an earthquake alarm. The sketch that I got from the internet does not retain the "on" state of the indicators(LED and buzzer)when it is triggered. I want to modify the sketch that it makes the LED and buzzer retains their "on" state when the sensor(accelerometer) is triggered. Could someone help me ?

Here is the code:

#include <Wire.h>
#include <MPU6050.h>

#define minval -5
#define maxval 3

MPU6050 mpu;


void setup()
{       
  Serial.begin(115200);
  pinMode(7,OUTPUT);
  pinMode(8,OUTPUT);

  delay (2000);

  // Initialize MPU6050
  Serial.println("Initialize MPU6050");

  while(!mpu.begin(MPU6050_SCALE_2000DPS, MPU6050_RANGE_2G))
  { 
    Serial.println("Could not find a valid MPU6050 sensor, check wiring!");
    delay(500);
  }

  mpu.setThreshold(3); 
  // Check settings
  checkSettings();
}



void checkSettings()
{
  Serial.println();
  Serial.print(" * Sleep Mode:        ");
  Serial.println(mpu.getSleepEnabled() ? "Enabled" : "Disabled");
  Serial.print(" * Clock Source:      ");
  switch(mpu.getClockSource())
  {
    case MPU6050_CLOCK_KEEP_RESET:
      Serial.println("Stops the clock and keeps the timing generator in reset"); 
      break;
    case MPU6050_CLOCK_EXTERNAL_19MHZ:
      Serial.println("PLL with external 19.2MHz reference"); 
      break;
    case MPU6050_CLOCK_EXTERNAL_32KHZ:
      Serial.println("PLL with external 32.768kHz reference");
      break;
    case MPU6050_CLOCK_PLL_ZGYRO:
      Serial.println("PLL with Z axis gyroscope reference");
      break;
    case MPU6050_CLOCK_PLL_YGYRO:
      Serial.println("PLL with Y axis gyroscope reference");
      break;
    case MPU6050_CLOCK_PLL_XGYRO:
      Serial.println("PLL with X axis gyroscope reference");
      break;
    case MPU6050_CLOCK_INTERNAL_8MHZ:
      Serial.println("Internal 8MHz oscillator"); 
      break;
  }

  Serial.print(" * Gyroscope:         ");
  switch(mpu.getScale())
  {
    case MPU6050_SCALE_2000DPS:
      Serial.println("2000 dps");
      break;
    case MPU6050_SCALE_1000DPS:
      Serial.println("1000 dps");
      break;
    case MPU6050_SCALE_500DPS:
       Serial.println("500 dps");
       break;
    case MPU6050_SCALE_250DPS:
       Serial.println("250 dps");
       break;
  }

  Serial.print(" * Gyroscope offsets: ");
  Serial.print(mpu.getGyroOffsetX());
  Serial.print(" / ");
  Serial.print(mpu.getGyroOffsetY());
  Serial.print(" / ");
  Serial.println(mpu.getGyroOffsetZ());
  Serial.println();
}

void loop()
{
  Vector rawGyro = mpu.readRawGyro();
  Vector normGyro = mpu.readNormalizeGyro();
  Serial.print(" Xraw = ");
  Serial.print(rawGyro.XAxis);
  Serial.print(" Yraw = ");
  Serial.print(rawGyro.YAxis);
  Serial.print(" Zraw = ");
  Serial.println(rawGyro.ZAxis); 

  if (normGyro.XAxis > maxval ||
      normGyro.XAxis < minval &&
      normGyro.YAxis > maxval ||
      normGyro.YAxis  < minval &&
      normGyro.ZAxis > maxval || 
      normGyro.ZAxis  < minval)
  {
    digitalWrite(7,HIGH);
    digitalWrite(8,HIGH);
    delay(300);
    digitalWrite(7,HIGH);
    digitalWrite(8,HIGH);
    delay(300);
    delay (1000);
  }
  else
  {
    digitalWrite(7,LOW);
    digitalWrite(8,LOW);
  }
  Serial.print(" Xnorm = ");
  Serial.print(normGyro.XAxis);
  Serial.print(" Ynorm = ");
  Serial.print(normGyro.YAxis);
  Serial.print(" Znorm = ");
  Serial.println(normGyro.ZAxis);
  delay(10);
}

Answer 1

• Define a (boolean: bool) variable, set it to false initially.

• When the sensor is activated, set the variable to true.

• Define something that should be able to disactivate the buzzer/LEDs. And if that happens, set the variable to FALSE. Maybe this is a reset button ?

• Than based on this variable set the buzzer and LEDs on or off.

So you get something like a global variable

bool alarmTriggered;

In setup:

alarmTriggered = false;

In loop:

if (AreSensorsTriggered(...)) // Create your own function
{
   alarmTriggered = true;
}
else if (IsResetButtonPressed(...)) // Create your own function
{
   alarmTriggered = false;
}


SetBuzzer(alarmTriggered); // Create a function that enables/disables buzzer
SetLEDs(alarmTriggered); // Create a function that enabled/disables LEDs