Published April 16, 2018 © GPL3+

Front Door Security Alarm

Can't afford an expensive security system, but still want to protect your home? This simple alarm is all you need to scare off any intruder!

BeginnerWork in progress10 hours1,520

Things used in this project

Hardware components

Particle Photon

PIR Motion Sensor (generic)

Jumper wires (generic)

ControlEverything.com Piezo Sensor

Breadboard (generic)

Software apps and online services

ThingSpeak API

Google Sheets

IFTTT Maker service

Story

This simple alarm is inexpensive, reliable, and easy to use. It is ideal for apartments or other places where a full security system cannot be installed. It is removable so it will not cause any permanent damage to walls and perfectly fits across a single entrance way; multiple motion sensors could be added to other entrances if wanted.

1 / 3 • Alarm and sensor setup

How it Works

The alarm operates using a PIR motion sensor on one breadboard with a particle photon that sends an alert to the cloud when motion is detected. The cloud sends a signal to the other photon which then sets off the alarm. Motion alerts are shown on the Particle console and using IFTTT are also sent to Google Sheets. The user can monitor the signals when they are sent to see if any unexpected guests have been in their home.

This graph shows the output given when the tripwire detects motion.

https://docs.google.com/spreadsheets/d/1TW_UaABEkObsw8eZVbstYR2m-1sojCorRcUa5RK5IgQ/edit#gid=0

Code

//Code for PIR sensor
int led = D7;       
int tripwire_input = D0;                           
int pirState = LOW;             
int val = 0;                    
#define publish_delay 16000
unsigned int lastPublish = 0;

int calibrateTime = 5000;      

void setup() {
    
    pinMode(led, OUTPUT);
    
    pinMode(tripwire_input, INPUT);
}

void loop() {
    
  if (calibrated()) {
      
    readTheSensor();

    reportTheData();
    }
}

void readTheSensor() {
    val = digitalRead(tripwire_input);
}

bool calibrated() {
    return millis() - calibrateTime > 0;
}

void setLED(int state) {
    digitalWrite(led, state);
}

void reportTheData() {
    
    if (val == HIGH) {
        
        if (pirState == LOW) {
            int value = 1;
          
          Particle.publish("ALERT!", "Someone is Approaching", 60);
          Particle.publish("thingSpeakWrite_D0", "{ \"1\": \"" + String(value) + "\", \"k\": \"NNXNV81JDXLW6J6E\"}", 60, PRIVATE);
         
          pirState = HIGH;
          setLED(pirState);
        }
    } else {
        if (pirState == HIGH) {
          
          Particle.publish("ALERT!", "Off", PRIVATE);
          pirState = LOW;
          setLED(pirState);
        }
    }
}

// This #include statement was automatically added by the Particle IDE.
#include <ThingSpeak.h>

int led = D7;

void setup() {
    
    pinMode(led, OUTPUT);

    Particle.subscribe("ALERT!", turnon);

}

void turnon(const char *event, const char *data) {
    
    if(strcmp(event, "ALERT!")==0){
        
        digitalWrite(led, HIGH);
        
        delay(5000);
        
        digitalWrite(led, LOW);
        
    }

}