Bluetooth-Based Home Security System - Electronic Engineering Guide
1. Introduction
A Bluetooth-Based Home Security System allows users to monitor and control security features such as door locks, motion detection, and alarms via Bluetooth-enabled smartphones. This project integrates an Arduino microcontroller, sensors, relays, and a Bluetooth module to provide basic home security functionality.
2. Objectives
• To design a wireless home security system using Bluetooth
communication.
• To implement password-protected access and alarm triggering mechanisms.
• To create a mobile app interface for remote control.
3. Components Required
• Arduino Uno or compatible microcontroller
• HC-05 Bluetooth module
• PIR motion sensor
• Magnetic reed switch or door sensor
• Buzzer or alarm module
• Relay module (optional for controlling lights/locks)
• Smartphone with Bluetooth terminal or custom app
• Jumper wires, resistors, breadboard
• 5V power adapter or battery
4. System Overview
The system uses Bluetooth communication to enable a smartphone to interact with an Arduino. The Arduino monitors inputs from sensors and can activate alarms or relays. Commands sent from the phone can arm/disarm the system or control outputs like door locks.
5. Circuit Design and Explanation
The Bluetooth module is connected to the Arduino via software serial. The PIR sensor and door switch are connected to digital input pins. The buzzer is connected to a digital output, and optional relays are used to control high-power devices.
6. Software and Programming
The Arduino is programmed to receive commands from the
Bluetooth module and respond by changing the system state. If sensors detect
intrusion when armed, the buzzer sounds. Code includes password validation.
Example Code Snippet:
#include <SoftwareSerial.h>
SoftwareSerial BT(10, 11);
int pir = 2;
int door = 3;
int buzzer = 4;
bool armed = false;
void setup() {
pinMode(pir, INPUT);
pinMode(door, INPUT);
pinMode(buzzer, OUTPUT);
BT.begin(9600);
Serial.begin(9600);
}
void loop() {
if (BT.available()) {
char cmd = BT.read();
if (cmd == '1') armed = true;
if (cmd == '0') armed = false;
}
if (armed && (digitalRead(pir)
|| digitalRead(door))) {
digitalWrite(buzzer, HIGH);
} else {
digitalWrite(buzzer, LOW);
}
}
7. User Interface (App Control)
Users can control the system using a Bluetooth terminal app or a custom mobile application. Basic apps send character commands (e.g., '1' to arm, '0' to disarm). Advanced apps can include GUI, login, and status monitoring.
8. Applications
• Home entry and intrusion detection
• Garage or gate monitoring
• Office and small shop security
• Low-cost wireless alert systems
9. Safety and Reliability Considerations
• Bluetooth range is limited (typically <10m).
• System should be protected against power failure (use battery backup).
• Avoid false alarms through sensor calibration.
• Consider encryption for communication if security is critical.
10. Conclusion
The Bluetooth-Based Home Security System is a practical project that demonstrates the integration of sensors, communication modules, and control logic. It offers a cost-effective and scalable solution for basic security needs in homes and small businesses.