Published June 15, 2020 © GPL3+

IOT based Door lock system

It is an IOT based door lock system which consists of a NodeMCU board. It is interfaced with a Sg90 which shows open and close of a door lock

BeginnerFull instructions provided2 hours19,529

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

Resistor 10k ohm

SparkFun Pushbutton switch 12mm

SG90 Micro-servo motor

Male/Female Jumper Wires

Software apps and online services

Blynk

Arduino IDE

circuito.io

Story

This project is an IOT based Door lock system which consists of a NodeMCU board which has a inbuilt ESP8266 wifi chip.It is interfaced to a Sg90(9g micro servo motor) which is used for simulating the locking and unlocking mechanism of the door Lock.The power and gnd lines are connected to 3.3v and GND pins of NodeMCU board.The signal wire is connected to D8 pin on the board.In case the wifi goes out and you need to lock the door, a button is also connected to D2 pin to manually close the door by just pressing it.All this is remotely controlled through the Blynk app and we also get e-mail notifications regarding opening and closing of the door.

The physical wiring of the circuit is given below.

The algorithm works like this:

->First install the blynk library in arduino.
->Then install Blynk app from playstore or appstore in your mobile phone.Create a account and login using that account.Then create a new project.
->Put a button and configure that button to virtual Pin 3(V3) and change the ON and OFF states to Lock And Unlock and change it to a switch.Also add a e-mail notifier to the project.

The final layout should look like:

->Connect the hardware according to the wiring diagram given above and upload the code with the auth token sent to your registered e-mail id and wifi SSID and password to which your laptop is connected.
->Once your board is online, we can press the play button and lock and unlock the door by pressing the button on the app and rotating the servo motor accordingly.If the servo is in OPEN state we can also manually close it by pressing the button.
->In this code the button is used as an interrupt.
->We can know if the servo is in OPEN or CLOSE state by reading the e-mail notifications given to our registered e-mail id in the form of HTML/text.

The code is pretty much self-explanatory

The working of the circuit is given below:

Code

IOT based Door Lock system

#define BLYNK_PRINT Serial
#define LED D4

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <Servo.h>

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

// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "Wifi SSID";
char pass[] = "Wifi password";

Servo servo;

uint8_t BUTTON=D2;
bool door;
int pos;

BLYNK_WRITE(V3)
{
  int pinValue=param.asInt();
  if(pinValue==1)
  {
      for (pos = 0; pos <= 180; pos += 5) { 
        servo.write(pos);              
        delay(15);
      }
      digitalWrite(LED,HIGH);                                                           //INVERTED STATUS OF LED PINS:HIGH means LOW
      door=true;
      Blynk.email("adarshbhola98@gmail.com","door_lock_unlock status","Door is closed");
  }
  else
  {
    for (pos = 180; pos >= 0; pos -= 5) { 
      servo.write(pos);              
      delay(15);
    }
    digitalWrite(LED,LOW);                                                          //LOW-->HIGH
    door=false;
    Blynk.email("adarshbhola98@gmail.com","door_lock_unlock status","Door is open");
  }
}

void IntCallback()
{
  if(door==false)
  {
      for (pos = 0; pos <= 180; pos += 5) { 
        servo.write(pos);              
        delay(15);
      }
      digitalWrite(LED,HIGH);                                                           //INVERTED STATUS OF LED PINS:HIGH means LOW
      door=true;
  }
  else
  {
    return;
  }
}

void setup()
{
  // Debug console
  Serial.begin(9600);

  Blynk.begin(auth, ssid, pass);
  // You can also specify server:
  //Blynk.begin(auth, ssid, pass, "blynk-cloud.com", 80);
  //Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8080);

  servo.attach(15);     //15--->D8
  pinMode(LED,OUTPUT);
  attachInterrupt(digitalPinToInterrupt(BUTTON),IntCallback,RISING);
}

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