Anti-Theft System using Ultrasonic Sensor and HC-05/ESP-01 with Blynk Mobile App

Overview:

Additional security in our homes and/or belongings not only aids in ensuring one’s safety but also reduces additional damage to our property. The most important aspect of a security system is its ability to maintain a wireless connection.  A system that is able to notify through our phones when there’s an intrusion is also most convenient for ease in monitoring. Thus, this project will introduce a simple anti-theft system using our Upgraded Arduino Uno Starter Kit with an integrated Blynk Application.

Hardware:

• Arduino Uno x 1

Software:

• Arduino IDE
• Blynk Mobile App
  • For Android
  • For iOS
• Blynk Library

Application Discussion

Wireless access, especially when it comes to security system, is important because this allows constant monitoring and control. Such functionalities can be achieved by our security system by using modules which enables wireless communication.

As such, this project introduces the use of wireless communication using either of the two modules: HC-05 or ESP-01. The security system generally consists of the Ultrasonic Sensor as an obstruction detector with LED lights, as well as a buzzer, as indicators.

Ultrasonic Sensor (HC-SR04)

The ultrasonic sensor is a sensor that is able to measure distances. It uses SONAR (Sound Navigation and Ranging) in order to determine the distance of an object. It also allows non-contact range detection. This is quite useful for security system because it minimizes the chance of damage on the actual system.

The connection of the ultrasonic sensor to the Arduino can be viewed in the table below:

HC-05 Bluetooth Module

There are several ways in achieving wireless communication and one of it is through Bluetooth. The HC-05 Bluetooth module uses serial communication which is commonly used in most electronics projects. It is also quite affordable for a device that enables a master-slave behavior. Such behavior allows wireless communication between two microcontrollers or any device with a Bluetooth functionality.

For this project, the HC-05 is used to receive information from the ultrasonic sensor and then relay it to the Blynk App. For the pins of the HC-05, the following connections are used:

 **This is viewed top to bottom from the product photo above—Pin label can also be found at the back of the Bluetooth module       .

ESP-01 Wi-Fi Module (ESP8266-01)

Aside from the HC-05 it is also possible to use a Wi-Fi Module to achieve wireless communication. The ESP8266-01 is a Wi-Fi module which allows microcontrollers to have access to a Wi-Fi network. It can also be reprogrammed to act as a standalone Wi-Fi connected device just by adding power! This module is quite versatile and is also affordable much like the HC-05.

Before proceeding with the ESP-01 route, the module MUST be configured first.

To configure the ESP-01, click HERE.

This module is an alternative route in creating this project. Wireless connection can be obtained using either the HC-05 or the ESP-01. The ESP-01 consists of 8 pins in total. Its corresponding connection with the Arduino, in this project can be viewed below.

*Arrangement of the pins is referenced from the above photo

Set-up the hardware

There will be two (2) hardware setup for this project. The first project will utilize HC-05 as its means for wireless communication while the other will use ESP-01.

Using the HC-05:

Using ESP-01:

Blynk App Setup

Download the Blynk App for your smartphone on Google Play or App Store.

Opening the application will immediately direct to the Log in page. User may opt to log in with their Facebook, Create a New Account, or Log in if they have an existing account already. Choose whichever option works best and once that’s done, we begin by creating a ‘New Project’.

The photos below show which options to select according to their respective module used. Bluetooth for the HC-05 option and Wi-Fi for the ESP-01. This is step is quite crucial to ensure seamless work experience with the Blynk App and the project.

After that, there will be an authentication token sent to the registered email address, make sure to check that. It the mail cannot be seen in the inbox folder make sure to also check the spam folder.

The next part will be the adding of components or widgets to achieve a good visual display for the project.

The next step is connecting to our Bluetooth/Wi-Fi module

For Bluetooth Connection

For Wi-Fi Connection

Change the connection type to Wi-Fi and it will automatically notify that a new device is connected. 

Just like in the bluetooth connection, the next step is adding of components or widgets to achieve a good visual display for the project.

With the Blynk App installed and ready to use, all that’s left is to setup the software side of our system.

Set-up the software

Open the Arduino IDE and upload the code on the Arduino. The codes can also be found on GitHub here.

Code for HC-05

#define trigPin 9
#define echoPin 10
#define onLED 4
#define detectLED 3
#define detectBuzz 7
/* Comment this out to disable prints and save space */
#define BLYNK_PRINT Serial

#include <SoftwareSerial.h>
SoftwareSerial SwSerial(11, 12); // RX, TX

#include <BlynkSimpleSerialBLE.h>

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "-----";

long duration;
int distance;

int acquiredValue;
int notifyVar = 0;

BlynkTimer timer1;
BlynkTimer timer2;

void myNormalTimerEvent()
{
  // You can send any value at any time.
  // Please don't send more that 10 values per second.
  Blynk.virtualWrite(V5, "System is ON");
}

void myDetectedTimerEvent()
{
  // You can send any value at any time.
  // Please don't send more that 10 values per second.
  Blynk.virtualWrite(V5, "Obstruction Detected");
}

void setup() {
  // put your setup code here, to run once:
  pinMode(echoPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(onLED, OUTPUT);
  pinMode(detectLED, OUTPUT);
  pinMode(detectBuzz, OUTPUT);
  
  digitalWrite(onLED, HIGH);
  
  SwSerial.begin(9600);
  Serial.begin(9600);
  Blynk.begin(SwSerial, auth);
  Serial.println("Waiting for connections...");

  // Setup a function to be called every second
  timer1.setInterval(1000L, myNormalTimerEvent);
  timer1.run();
}

void loop() {
  Blynk.run();
  
  ultrasonicFunction();

  if (distance < 50) {
    digitalWrite(onLED, LOW);
    digitalWrite(detectLED, HIGH);

    tone(detectBuzz, 1000);

    if (notifyVar == 0) {
      notifyVar++;
      
      Blynk.notify("!!Obstruction Detected!!");
      // Setup a function to be called every second
      timer2.setInterval(1000L, myDetectedTimerEvent);
      timer2.run();
    }
  }

  if (acquiredValue == 1) {
    digitalWrite(onLED, HIGH);
    digitalWrite(detectLED, LOW);

    noTone(detectBuzz);

    notifyVar--;

    acquiredValue = 0;
    Blynk.notify("System Reset");
    // Setup a function to be cal led every second
    timer1.setInterval(1000L, myNormalTimerEvent);
    timer1.run();
  }
}

void ultrasonicFunction() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance= duration*0.034/2;
  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.println(distance);
}

BLYNK_WRITE(V1)
{
  acquiredValue = param.asInt(); // assigning incoming value from pin V1 to a variable
}

Code Breakdown

The code for controlling using the Blynk app is based on the Blynk Example Browser.

Make sure to input the Board as Arduino UNO and the Connection as HC05 or HC06. Afterwards, input the Auth Token that could be found in your Blynk App by pressing the nut icon on your project screen.

You can now browse the Examples provided. For this project, we will be using the Get Data to listen if you have pressed the button in the App and the Push Data to change the display in our Blynk App.

• Setting up the Bluetooth connection to Blynk

#include <SoftwareSerial.h>
SoftwareSerial SwSerial(11, 12); // RX, TX

#include <BlynkSimpleSerialBLE.h>

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "YourAuthToken";

This is what you'll see in the Blynk Example Browser. Make sure to input this in your void setup() afterwards to turn on communication of the HC-05 and start communicating with your Blynk App.

•  void myNormalTimerEvent()

This function is from the Push Data example from the Blynk Example Browser. In this case, it was renamed to myNormalTimerEvent(). This will utilize the BlynkTimer function and for this function, it will be named timer1. This function will changed the label on virtual pin 5 (V5) of the Blynk App to "System is ON". It will only work if it is called in the code with:

timer1.setInterval(1000L, myNormalTimerEvent);
timer1.run();

• void myDetectedTimerEvent()

This function is like the myNormalTimerEvent() and will only activate if the ultrasonic sensor detected an obstruction. In this case, it was renamed to myDetectedTimerEvent(). This will utilize the BlynkTimer function and for this function, it will be named timer2. This function will changed the label on virtual pin 5 (V5) of the Blynk App to "Obstruction Detected". It will only work if it is called in the code with:

timer2.setInterval(1000L, myDetectedTimerEvent);
timer2.run();

• BLYNK_WRITE(V1)

This function is from the Get Data example from the Blynk Example Browser. This function is checking if the button on your Blynk App that was assigned on virtual pin 1 (V1) has been pressed or not. We get this by using the function param.asInt() and storing it in a variable called acquiredValue. This variable will be equal to 1 if pressed.

• void setup()

Code for ESP-01

#define BLYNK_PRINT Serial

#include <ESP8266_Lib.h>
#include <BlynkSimpleShieldEsp8266.h>

#define trigPin 9
#define echoPin 10
#define onLED 4
#define detectLED 3
#define detectBuzz 7

long duration;
int distance;

int acquiredValue;
int notifyVar = 0;

/* Comment this out to disable prints and save space */
#include 
SoftwareSerial EspSerial(12, 11); // RX, TX

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "5c6pFHdq71CuypOW2cRKpN22CmlJ5iYE";

// Your WiFi credentials.
// Set password to "" for open networks.

//Replace the ---- with your SSID and Password

char ssid[] = "------"; 
char pass[] = "------";

// Your ESP8266 baud rate:
#define ESP8266_BAUD 9600

ESP8266 wifi(&EspSerial);

void setup() {
  // put your setup code here, to run once:

  // Debug console
  Serial.begin(9600);
  delay(10);
  
  EspSerial.begin(ESP8266_BAUD);
  delay(10);

  Blynk.begin(auth, wifi, ssid, pass);
  Blynk.virtualWrite(V5, "System is ON");

  pinMode(echoPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(onLED, OUTPUT);
  pinMode(detectLED, OUTPUT);
  pinMode(detectBuzz, OUTPUT);
  
  digitalWrite(onLED, HIGH);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(Blynk.connected()) {
    Blynk.run();
    ultrasonicFunction();

    if (distance < 50) {
      digitalWrite(onLED, LOW);
      digitalWrite(detectLED, HIGH);
  
      tone(detectBuzz, 1000);
  
      if (notifyVar == 0) {
        notifyVar++;
  
        Blynk.notify("!!Obstruction Detected!!");
        Blynk.virtualWrite(V5, "Obstruction Detected");
      }
    }
    if (acquiredValue == 1) {
      digitalWrite(onLED, HIGH);
      digitalWrite(detectLED, LOW);
  
      noTone(detectBuzz);
  
      notifyVar--;
  
      acquiredValue = 0;
      Blynk.notify("System Reset");
      Blynk.virtualWrite(V5, "System is ON");
    }
  }
}

void ultrasonicFunction() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance= duration*0.034/2;
  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.println(distance);
}

BLYNK_WRITE(V1)
{
  acquiredValue = param.asInt(); // assigning incoming value from pin V1 to a variable
}

Code Breakdown

 The code for controlling using the Blynk app is based on the Blynk Example Browser.

Make sure to input the Board as Arduino UNO and the Connection as ESP8266 WiFi Shield. Afterwards, input the Auth Token that could be found in your Blynk App by pressing the nut icon on your project screen.

Copy the sketch from the Blynk Example browser and comment out #define EspSerial Serial1 and uncomment the following while changing the EspSerial to (12,11).

#include <SoftwareSerial.h> 
SoftwareSerial EspSerial(12, 11); // RX, TX

Make sure to configure your ESP-01s to 9600 baud rate. Otherwise, the default would be 115200 baud rate.

You can now browse the Examples provided. For this project, we will be using the Get Data to listen if you have pressed the button in the App, and unlike the Bluetooth output, we won't be using timers in this project. Instead, we will utilize Blynk.write().

• BLYNK_WRITE(V1)

This function is from the Get Data example from the Blynk Example Browser. This function is checking if the button on your Blynk App that was assigned on virtual pin 1 (V1) has been pressed or not. We get this by using the function param.asInt() and storing it in a variable called acquiredValue. This variable will be equal to 1 if pressed.

• void setup()

Output

for Bluetooth (HC-05)

Once the code has been uploaded go back to your Blynk App. The prompt should say that the system is ON and will send you a notification if an obstruction is detected. The reset button will switch off the alarm and await for another detected obstruction.

for Wi-Fi Module (ESP-01)

Conclusion

Upon working on the simple anti-theft system, we were able to explore two ways in achieving a wireless communication. The two options we explored were the Bluetooth route which used the HC-05 module and the Wi-Fi route which made use of the ESP-01. Not only that, we also utilized various components such as the ultrasonic sensor, the LED, and the buzzer. This simple anti-theft system cannot be commercially used however such knowledge may be applied in higher-scale projects or applications.

To find more useful and fun projects for you to try, you may head on to KnowledgeBase and Tutorials.

References

www.microchip.ua/wireless/esp01.pdf

https://components101.com/wireless/hc-05-bluetooth-module

https://randomnerdtutorials.com/complete-guide-for-ultrasonic-sensor-hc-sr04/