Published May 29, 2020 © CC BY

Limit the crowd to prevent the spread of COVID-19

A cheap and effective method to limit the crowd in public places - such as shopping malls, supermarkets, etc - and public transport vehicles

BeginnerFull instructions provided2 hours8,695

Limit the crowd to prevent the spread of COVID-19

Things used in this project

Hardware components

Arduino UNO

Solderless Breadboard Half Size

You will only be needing the power rail of this breadboard

IR tracking sensor module

Ultrasonic Sensor - HC-SR04 (Generic)

Could be used instead of the IR tracking sensor module

Adafruit RGB Backlight LCD - 16x2

SG90 Micro-servo motor

Male/Female Jumper Wires

Male/Male Jumper Wires

Software apps and online services

Arduino IDE

Story

The World Health Organization, WHO, has advised people to stay away from crowded places to protect themselves from the spread of Coronavirus disease. Even though people practice social distancing, it may not be effective when they are present in crowded places. I came up with this idea after I read the WHO guidelines about preventing the spread of COVID-19.

Aim/ Objective

This project is an automatic, cheap and effective way of limiting the crowd in public places - such as shopping malls, supermarkets, offices - and public transport vehicles, such as buses and trains.

Using a human to limit the number of people in a particular place would not be as effective as using an automatic system due to the lack of staff members in some areas.This prototype can be used in real-life situations by replacing the servo motor with a solid state relay module.

The solid state relay module will control the motor operating the automatic sliding doors in buildings and vehicles. There will be a slight change in code when replacing the servo motor.

How it works

1 / 2

If a person is going to enter the building or vehicle, he/ she can wave or hover his/ her hand over the ultrasonic/ IR tracking sensor module. If an IR tracking sensor module is used, it will send a LOW signal to the Arduino Uno microcontroller and according to my program, the door will be opened.

Before hovering over the sensor, the person can wash his/ her hands using a touchless faucet (https://www.hackster.io/RUCKSIKAA/automatic-faucet-touchless-using-arduino-for-covid-19-369b18).

In my model, I have used a servo motor to open/ close the door. The door will be opened when the servo motor rotates 90 degrees.

If an ultrasonic sensor module is used, the door will be opened when the sensor detects an obstacle within 5 cm away from itself.The door will remain open for 5 seconds and the value stored in the count variable will increase by one after the door is closed. The count variable denotes the number of people inside a building or vehicle.

If the value stored in the count variable reaches the maximum occupancy value, the LCD display module will show that no one could enter and the door will remain closed until someone leaves the building.I have attached an IR tracking sensor module on the inside of the box (modelled as the building/ vehicle) as well. The process will be the same as that mentioned above, but the difference is that the value stored in the count variable will decrease by one as a person is leaving the building.

*Note: The maximum occupancy in this case is the maximum number of people who can enter the building or vehicle without crowding it.

Here's a video showing how this project works:

Code

Code

// LIMIT THE CROWD TO PREVENT THE SPREAD OF COVID-19
// ARDUINO PROJECTS BY R
// AUTHOR: RUCKSIKAA RAAJKUMAR
#include <LiquidCrystal_I2C.h>
#include <Wire.h>
#include <Servo.h>
#define trig 4
#define echo 3
const int out_sensor=5;
int out_state;
Servo servo;
LiquidCrystal_I2C lcd(0x27,16,2);
int count; // Variable to store the number of people inside
int limit = 15; // The maximum occupancy 
long duration;
int distance;
void setup() { // put your setup code here, to run once:
  pinMode(out_sensor, INPUT); // Configure the pin of the IR tracking sensor as INPUT
  pinMode(trig, OUTPUT); // Configure the trig pin of the Ultrasonic sensor module as OUTPUT as it emits ultrasonic waves (pulse)
  pinMode(echo, INPUT); // Configure the echo pin of the echo pin as INPUT
  Serial.begin(9600);
  servo.attach(9); // Servo motor is connected to D9
  servo.write(0); // Set the initial position of servo motor as 0 degrees.
  lcd.begin();
}
void loop() { // put your main code here, to run repeatedly:
  if(count==limit){ // If maximum occupancy is reached
    lcd.clear();
    lcd.setCursor(1,0);
    lcd.print("Max. occupancy");
    lcd.setCursor(5,1);
    lcd.print("reached");
  }else{ // If maximum occupancy is not reached
    lcd.clear();
    lcd.print("No. of people=");
    lcd.print(count);
  }
  digitalWrite(trig, LOW);
  delayMicroseconds(5);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  duration = pulseIn(echo, HIGH); // Calculate time taken (in microseconds) for the pulse emitted by the trigger pin to reach the echo pin.
  distance = (duration/2) * (331.3/10000); // Calculate the distance from the sensor to the obstacle in cm, using the speed of sound in air(m/s) and the time taken (stored in duration variable)
  Serial.println(distance);
  out_state=digitalRead(out_sensor); 
  Serial.println(count);
  if(out_state==LOW){ // If anyone hovers over the IR sensor
    count--; // Value stored in count variable will be decreased by one as the person is exiting the building or vehicle
    servo.write(90); 
    delay(5000); // Door will remain open for 5 seconds
    servo.write(0);
    if(count<0){
      count=0;
    }
  }
  if(distance<5){
    if(count>limit){ // If value stored in count variable is greater than maximum occupancy
      lcd.clear();
      lcd.print("You can't enter");
      lcd.setCursor(6,1);
      lcd.print("now");
      delay(2000);
    }else{
      count++; // Count will increase by one as a person is entering
      servo.write(90);
      delay(5000);
      servo.write(0);
    }
  } 
}

Credits

Rucksikaa Raajkumar

43 projects • 93 followers

Amateur Arduino Developer. Undergraduate. YouTuber (https://www.youtube.com/c/RucksikaaRaajkumar/videos) and Blogger (Arduino Projects by R)

Limit the crowd to prevent the spread of COVID-19

Things used in this project

Hardware components

Software apps and online services

Story

Aim/ Objective

How it works

Schematics

Schematic

Connections

Connections (2)

Arduino Uno microcontroller board

Code

Code

Credits

Rucksikaa Raajkumar

Comments

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Limit the crowd to prevent the spread of COVID-19

Limit the crowd to prevent the spread of COVID-19

Things used in this project

Hardware components

Software apps and online services

Story

Aim/ Objective

How it works

Schematics

Schematic

Connections

Connections (2)

Arduino Uno microcontroller board

Code

Code

Credits

Rucksikaa Raajkumar

Comments

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