International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 08 Issue: 11 | Nov 2021 www.irjet.net p-ISSN: 2395-0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1645 Arduino UNO Based Visitors Counting System for Vaccination Rooms Sakshi Gupta 1 , Sreenitya Mandava 2 , B. Chandrakanth Reddy 3 1,2,3 School of Computer Science and Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India ----------------------------------------------------------------------***--------------------------------------------------------------------- Abstract – With the era of social distancing, there is a need for maintaining a specific threshold for the number people be it in a vaccination room or public gatherings. Visitors Counting System is used to count and keep track of number of people in the room and can effectively be used for the halls or rooms during vaccination drives and any form of gatherings, we can set a maximum limit of people that can enter room once the maximum limit reaches people needs to wait until the count gets decreased. Here we aimed to implement such a system that maintains the correct count of visitors inside the room. To do that two infrared sensors are used one at the entrance which increases the count value when visitor passes through the sensor and other at exit of the room which decrements the count of visitor when they pass through exit door. This system can be implemented anywhere with simple components and can be accessed online through a smartphone or a computer enabling everyone to follow the COVID norms. Key Words: Visitors Counting System, Arduino UNO, Infrared LED, ESP32, LCD. 1. INTRODUCTION Internet of Things is a fast growing technology and has revolutionized every field in the past decade. The idea of IoT is so adaptable, flexible, and universal. In this work, IOT components have been used to build a visitor counter which can be monitored online. This visitor counter can be part of few automation systems or smart home system. The other important application we are focusing on is its use in vaccination rooms to monitor the number of people i.e. patients and medical staff so as to practice good medical health hygiene. This is an essential in the present era of social distancing. It can also be used to maintain the threshold, maximum number of people allowed, for public and social gatherings and follow the protocols. There are various other numerous areas in which such a technology would come to play. With the increase of population, management of this vast number has been becoming difficult year after year. There are many existing methods used by different sectors to count visitors effectively without hindrance. But each method has its drawbacks like effectiveness or cost or both of them. Here, after going through some prominent papers on this topic, we aim to present a simple yet effective visitors counting system that can be accessed online through a mobile or web application from anywhere in the world. This can help anyone who wants to keep a count of their visitors and follow the COVID norms for any public gathering, be it small or big. The visitors counting system is built on Arduino UNO. Arduino UNO is the popular prototyping boards. The Arduino is interfaced with an ESP32 Wi-Fi modem to connect with an internet router and access the cloud server. The counter circuit is designed using Infrared sensors. The Arduino based IoT device passes the count of the visitors in the room to the cloud. As the data will be updated on the cloud, it can be accessed online using any smartphone or computer. The ESP32 Wi-Fi Module is used to connect with the Arduino with a Wi-Fi router, so that it can access the cloud. It's a self-contained SOC with integrated TCP/IP protocol stack which can access a Wi-Fi network. The ESP32 is capable of hosting an application or offloading all Wi-Fi networking functions from different application processor. 1.1 Components Used 1. Arduino UNO R3 development board 2. Sensor module (infrared LED, photodiode) 3. Jumper wires 4. Potentiometer 5. Bread board 6. 16 X 2 LCD 7. ESP32 Wi-Fi module 2. LITERATURE REVIEW [1] Research work presented in this paper proposes an IoT person counter implemented with two different technologies, motion and ultrasonic. The information count by a person counter device can be used in different scenarios, such as to ensure security of access to a room, or to maintain and regulate the temperature of a room. Algorithms have been suggested to carry out the management of the information provided by the sensors. As a result of the proposal, this experiment concludes that in controlled environments, where there are not many people transiting, both methods had a considerable accuracy. In contrast, in scenarios in which the flux of people is significant. [2] This work incorporates the following, a PIC 16F877A microcontroller, IR sensors, transistors, resistors, diodes, LEDs, LCD, and a buzzer. The two pairs of infrared sensor (IR) which consists of a transmitter (TX) and a receiver (RX) is mounted face to face across the doorway. Both sensors are positioned at the entry with distance apart. This infers upon the approach of a person the installed two pair sensors are triggered by the obstruction. The direction