Project 3.15.1: Emergency Panic Station

Description	Press and hold the push button for 3 seconds to activate an emergency alert. The LED flashes in an SOS pattern while the buzzer emits a pulsing siren to simulate an emergency panic station.
Use case	This project can be used as a prototype for emergency alert systems, panic buttons, home security systems, elderly assistance devices, and personal safety alarms.

Components (Things You will need)

Building the circuit

Things Needed:

• Arduino Uno = 1
• Arduino USB cable = 1
• Push button = 1
• LED = 1
• Buzzer = 1
• Jumpr Wires
• 220Ω resistor

Mounting the component on the breadboard

Step 1: Carefully mount the push button, LED and buzzer on the breadboard, ensuring proper orientation and enough spacing for easy wiring.

NB: Ensure the LED polarity is correct and place the push button across the centre gap of the breadboard before wiring.

WIRING THE CIRCUIT

Step 2: Connect one terminal of the push button to digital pin 2 on the Arduino Uno. Connect the opposite terminal of the push button to GND.

Step 2: Connect the LED anode (long leg) to digital pin 8 through the 220 Ω resistor. Connect the LED cathode (short leg) to GND.

Step 2: Connect the positive (+) terminal of the buzzer to digital pin 9. Connect the negative (-) terminal of the buzzer to GND.

Make sure to connect the Arduino USB cable to the Arduino board.

PROGRAMMING

Step 1: Open your Arduino IDE. See how to set up here: Getting Started.

Step 2: Write the complete program implementing the system logic with appropriate pin definitions, setup configuration, and the main control loop.

// Pin Definitions
const int BUTTON_PIN = 2;
const int LED_PIN = 8;
const int BUZZER_PIN = 9;

// Variables
unsigned long buttonPressTime = 0;
bool alarmTriggered = false;

// -------------------------
// Setup
// -------------------------
void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  digitalWrite(LED_PIN, LOW);
  digitalWrite(BUZZER_PIN, LOW);

  Serial.begin(9600);
}

// -------------------------
// Main Loop
// -------------------------
void loop() {

  // Detect long button press (3 seconds)
  if (digitalRead(BUTTON_PIN) == LOW) {

    if (buttonPressTime == 0) {
      buttonPressTime = millis();
    }

    if (millis() - buttonPressTime >= 3000) {
      alarmTriggered = true;
    }

  } else {
    buttonPressTime = 0;
  }

  // Run alarm if activated
  if (alarmTriggered) {
    playSOS();
    playSiren();
  }
}

// -------------------------
// SOS LED Pattern
// -------------------------
void playSOS() {

  // S (...)
  for (int i = 0; i < 3; i++) {
    flashLED(200);
  }

  // O (---)
  for (int i = 0; i < 3; i++) {
    flashLED(600);
  }

  // S (...)
  for (int i = 0; i < 3; i++) {
    flashLED(200);
  }

  delay(800);
}

// -------------------------
// Flash LED
// -------------------------
void flashLED(int duration) {
  digitalWrite(LED_PIN, HIGH);
  delay(duration);
  digitalWrite(LED_PIN, LOW);
  delay(200);
}

// -------------------------
// Pulsing Siren
// -------------------------
void playSiren() {

  for (int freq = 700; freq <= 1200; freq += 20) {
    tone(BUZZER_PIN, freq);
    delay(10);
  }

  for (int freq = 1200; freq >= 700; freq -= 20) {
    tone(BUZZER_PIN, freq);
    delay(10);
  }

  noTone(BUZZER_PIN);
}

Step 7: Save your code. See the Getting Started section

Step 8: Select the arduino board and port See the Getting Started section:Selecting Arduino Board Type and Uploading your code.

Step 9: Upload your code. See the Getting Started section:Selecting Arduino Board Type and Uploading your code

CONCLUSION

Congratulations! You have successfully built an Emergency Panic Station using a push button, LED, buzzer, and Arduino Uno. In this project, you learned how to detect a sustained button press, introduce timing into a program, and coordinate multiple output devices to create an emergency alert system. This project demonstrates important concepts used in real-world security systems, emergency response devices, and personal safety equipment. Continue experimenting by adding additional indicators, wireless communication, or sensors to create even more advanced emergency notification systems.