Smart Home Security System: PIR, Camera and Siren India

A smart home security system with PIR, camera, and siren for India provides 24/7 protection tailored to Indian threat scenarios: unauthorised entry, domestic help monitoring, package theft, and terrace intrusion. This complete DIY project uses ESP32-CAM for video capture, HC-SR501 PIR for motion detection, and an ESP8266 controller that sends instant Telegram photo alerts and activates a 12V siren, all for under Rs 2,500 total.

Table of Contents

• Indian Home Security Threat Model
• Hardware: ESP32-CAM, PIR, Siren, and Power
• ESP32-CAM Setup and Photo Capture
• PIR Motion Detection and Zones
• Telegram Bot Alerts with Photo Snapshots
• Siren and Strobe Light Integration
• Home Assistant Integration for Armed/Disarmed Modes
• Frequently Asked Questions

Indian Home Security Threat Model

Indian homes face specific security challenges:

• Domestic help monitoring: Alert when domestic helper arrives/departs during defined hours
• Terrace and balcony access: Common break-in points in Indian apartment buildings
• Package theft: Doorstep delivery theft increased significantly after e-commerce growth
• After-dark garden/compound intrusion: Especially relevant in independent houses and farm properties
• False alarms: Pets (common in Indian homes), cleaning staff, family members – smart detection zones prevent nuisance alerts

Hardware: ESP32-CAM, PIR, Siren, and Power

Complete BOM with India prices (2025):

• ESP32-CAM (AI Thinker) with OV2640 camera: Rs 320 per unit
• HC-SR501 PIR sensor: Rs 60 per zone (buy 4-6 for a 2BHK)
• 12V 6-tone siren: Rs 150 (automotive type, available on Amazon India)
• 12V strobe light: Rs 120 (adds visual deterrent)
• 5V 3A USB adapter: Rs 200 (powers ESP32-CAM and ESP8266 hub)
• 12V 2A adapter: Rs 180 (for siren/strobe)
• 2N2222 transistor + 1N4007 flyback diode: Rs 10 (for siren drive)
• Total BOM for 3-camera + 4-PIR system: approximately Rs 2,200

ESP32-CAM Setup and Photo Capture

#include <Arduino.h>
#include "esp_camera.h"
#include <WiFi.h>

// AI Thinker ESP32-CAM pin definitions
#define PWDN_GPIO_NUM  32
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM   0
#define SIOD_GPIO_NUM  26
#define SIOC_GPIO_NUM  27
#define Y9_GPIO_NUM    35
#define Y8_GPIO_NUM    34
// ... (full pin list from Espressif docs)

camera_config_t config;
config.ledc_channel = LEDC_CHANNEL_0;
config.pixel_format = PIXFORMAT_JPEG;
config.frame_size = FRAMESIZE_VGA;  // 640x480
config.jpeg_quality = 12;  // 0-63, lower=better quality
config.fb_count = 1;

esp_err_t err = esp_camera_init(&config);
if (err != ESP_OK) {
    Serial.printf("Camera init failed: 0x%x", err);
    return;
}

// Capture a frame
camera_fb_t* fb = esp_camera_fb_get();
if (!fb) return;  // capture failed
// fb->buf contains JPEG data, fb->len is size
esp_camera_fb_return(fb);

PIR Motion Detection and Zones

// HC-SR501 sensitivity: turn trimmer CW for longer range (up to 7m)
// Delay trimmer: set to minimum (2-3 seconds) for fastest re-trigger

#define PIR_DOOR     GPIO_NUM_13  // Front door zone
#define PIR_BALCONY  GPIO_NUM_14  // Balcony zone
#define PIR_TERRACE  GPIO_NUM_15  // Terrace zone
#define PIR_KITCHEN  GPIO_NUM_16  // Kitchen/back door zone

// Interrupt-driven for fast response
void IRAM_ATTR pirISR_door() {
    if (!armState) return;  // system disarmed
    pirTriggered = ZONE_DOOR;
    xSemaphoreGiveFromISR(alertSemaphore, NULL);
}

void setup() {
    attachInterrupt(PIR_DOOR, pirISR_door, RISING);
    attachInterrupt(PIR_BALCONY, pirISR_balcony, RISING);
}

Add a 30-second cool-down per zone to prevent alert flooding. After initial detection and photo capture, wait 30 seconds before allowing the same zone to re-trigger.

Telegram Bot Alerts with Photo Snapshots

Create a Telegram bot via @BotFather and get your bot token and chat ID.

#include <UniversalTelegramBot.h>
#include <WiFiClientSecure.h>

#define BOT_TOKEN "YOUR_BOT_TOKEN"
#define CHAT_ID   "YOUR_CHAT_ID"  // get from @userinfobot

WiFiClientSecure client;
UniversalTelegramBot bot(BOT_TOKEN, client);

void sendSecurityAlert(const char* zone, camera_fb_t* fb) {
    String msg = "ALERT: Motion in " + String(zone) + "n";
    msg += "Time (IST): " + getISTTime() + "n";
    msg += "System: ARMED";
    
    // Send text alert first (fast)
    bot.sendMessage(CHAT_ID, msg, "");
    
    // Send photo (uses multipart form upload)
    bot.sendPhoto(CHAT_ID, fb->buf, fb->len, "image/jpeg");
}

The Telegram bot delivers alerts to your phone even when you have no data connection via WiFi calling – SMS fallback ensures you are always notified.

Siren and Strobe Light Integration

// Siren drive via 2N2222 NPN transistor
// ESP32 GPIO can only sink/source 40mA; 12V siren needs transistor switch

void activateSiren(int durationSeconds) {
    digitalWrite(SIREN_PIN, HIGH);   // turn on siren via transistor
    digitalWrite(STROBE_PIN, HIGH);  // visual deterrent
    delay(durationSeconds * 1000);
    // Ensure auto-off even if MQTT disable command missed
    digitalWrite(SIREN_PIN, LOW);
    digitalWrite(STROBE_PIN, LOW);
}

// MQTT to silence: subscribe to home/security/siren/set
void mqttCallback(char* topic, byte* payload, unsigned int length) {
    if (strcmp(topic, "home/security/siren/set") == 0) {
        if (strncmp((char*)payload, "OFF", 3) == 0)
            digitalWrite(SIREN_PIN, LOW);
    }
}

Home Assistant Integration for Armed/Disarmed Modes

Add an alarm panel in Home Assistant:

# configuration.yaml
alarm_control_panel:
  - platform: manual
    name: Home Security
    arming_time: 30     # 30 sec grace period after arming
    delay_time: 20      # 20 sec grace period on entry before alarm
    trigger_time: 120   # siren runs for 2 minutes
    armed_home:
      disarmed_state_triggers:
        - 'disarmed'
    armed_away:
      disarmed_state_triggers:
        - 'disarmed'

Use HA automations to: arm when everyone leaves (device tracker shows all phones away from home), disarm when family member’s phone returns, and escalate to SMS/phone call if siren runs >60 seconds without disarm.

Frequently Asked Questions

Will the PIR sensor trigger on pets?

Standard HC-SR501 is pet-immune if installed correctly. Mount 2.1-2.4m high, angled downward at 10-15 degrees. Dogs and cats below 25kg typically do not trigger if the PIR looks across the room rather than straight down. For guaranteed pet immunity, use a dual-technology detector (PIR + microwave) like the DSC BV-300 (Rs 1,200).

How do I power the system during a power cut?

Add a 12V 7Ah sealed lead-acid battery (Rs 400) with a TP4056-style 12V charging circuit. At 100mA average draw (4 cameras + PIRs), a 7Ah battery provides 70 hours of backup. The siren draw (400mA for 2 minutes) barely affects this.

Can Telegram alerts work during mobile data outage?

No, Telegram requires internet. Add an SMS backup: SIM800L module (Rs 280) sends SMS via a spare Jio/BSNL SIM when WiFi/internet is unavailable. Use the SIM800L’s AT+CMGS command for SMS sending.

Is it legal to install a siren in an Indian apartment building?

Residential societies can regulate noise-making devices under society bylaws. A 90dB indoor siren activating for 2 minutes during genuine intrusion is generally acceptable. For terrace or outdoor sirens, check with your housing society RWA. Avoid sirens above 120dB in dense urban areas (Mumbai, Delhi).

How do I prevent false alarms from insects walking across PIR?

Insects, spiders, and ceiling lizards (common in Indian homes) are a major PIR false alarm source. Use a tight mesh cover over the PIR Fresnel lens, or switch to microwave-PIR dual technology sensors. Software debouncing also helps: require 2 PIR pulses within 3 seconds before triggering an alert.

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