Standalone Alarm With PIR Sensor and Responsive RGB Strip

This project is a standalone Arduino-based motion alarm system designed for small-scale home or workspace security. The system integrates motion detection, visual alerts, audio alerts, and user control through buttons and a display.

Key Features:

1. Arm/Disarm Functionality:
2. A push button allows the user to enable or disable the alarm. The system indicates the current state on a 16×2 I²C LCD display: “DISARMED” or “ARMED”.
3. Panic Mode:
4. A separate panic button immediately triggers the alarm regardless of whether it is armed, displaying “PANIC!” on the LCD.
5. Motion Detection:
6. A PIR motion sensor monitors the area. When motion is detected while armed, the alarm triggers automatically, showing “MOTION!” on the LCD.
7. Visual Alerts:
8. The system uses three LEDs to indicate status:
9. → System disarmed
10. → System armed but idle
11. → Alarm triggered (flashes)
12. Audio Alerts:
13. A buzzer produces a short beep when arming/disarming and a siren-like tone when the alarm is triggered.
14. LCD Feedback:
15. The 16×2 I²C LCD displays the current status and blinks messages when the alarm is active, giving a clear visual indicator of the system state.

1x Arduino Uno Rev3

1x Jumper wires (generic)

2x Generic button

1x Analog RGB LED strip

1x 16x2 LCD display with I²C interface

1x 5V power supply

1x Buzzer

1x PIR sensor

Wire Supplies as seen in the Schematic. NOTE that the RGB Led represents the RGB Led Strip

button-pin8

panicButton-pin2

buzzer-pin9

PIR sensor-pin10

greenLed-pin5

Blue led-pin6

Red led-pin11

Upload the required Code:

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int buttonPin = 8; // arm/disarm

const int panicButton = 2; // panic trigger

const int buzzerPin = 9;

const int pirPin = 10;

const int greenLed = 5;

const int blueLed = 6;

const int redLed = 11;

bool alarmEnabled = false;

bool alarmTriggered = false;

bool panicMode = false;

int lastButtonState = HIGH;

int lastPanicState = HIGH;

bool lcdState = true;

void setup() {

pinMode(buttonPin, INPUT_PULLUP);

pinMode(panicButton, INPUT_PULLUP);

pinMode(buzzerPin, OUTPUT);

pinMode(pirPin, INPUT);

pinMode(greenLed, OUTPUT);

pinMode(blueLed, OUTPUT);

pinMode(redLed, OUTPUT);

lcd.init();

lcd.backlight();

lcd.print("Alarm Disabled");

digitalWrite(greenLed, HIGH);

}

void loop() {

int buttonState = digitalRead(buttonPin);

int panicState = digitalRead(panicButton);

// ARM / DISARM BUTTON

if (lastButtonState == HIGH && buttonState == LOW) {

alarmEnabled = !alarmEnabled;

alarmTriggered = false;

panicMode = false;

lcd.clear();

lcd.print(alarmEnabled ? "Alarm Enabled" : "Alarm Disabled");

digitalWrite(redLed, LOW);

// Short beep on toggle

tone(buzzerPin, 1500);

delay(120);

noTone(buzzerPin);

delay(250);

}

// PANIC BUTTON

if (lastPanicState == HIGH && panicState == LOW) {

alarmTriggered = true;

panicMode = true;

lcd.clear();

}

lastButtonState = buttonState;

lastPanicState = panicState;

// PIR MOTION

if (alarmEnabled && digitalRead(pirPin) == HIGH) {

alarmTriggered = true;

panicMode = false;

}

// NORMAL STATUS

if (!alarmTriggered) {

noTone(buzzerPin);

digitalWrite(redLed, LOW);

if (!alarmEnabled) {

digitalWrite(greenLed, HIGH);

digitalWrite(blueLed, LOW);

} else {

digitalWrite(greenLed, LOW);

digitalWrite(blueLed, HIGH);

}

}

// ALARM ACTIVE

if (alarmTriggered) {

// FLASH LEDs

digitalWrite(greenLed, HIGH);

digitalWrite(blueLed, HIGH);

digitalWrite(redLed, HIGH);

// HIGHER WAILING ALARM SOUND

tone(buzzerPin, 1600); // high tone

delay(100);

tone(buzzerPin, 1000); // lower tone

delay(100);

// LCD blinking message

lcd.clear();

if (lcdState) {

lcd.print(panicMode ? "PANIC!" : "MOTION!");

lcd.setCursor(0,1);

lcd.print("Press button");

}

lcdState = !lcdState;

// Turn off LEDs briefly

digitalWrite(greenLed, LOW);

digitalWrite(blueLed, LOW);

digitalWrite(redLed, LOW);

noTone(buzzerPin);

delay(100);

}

}