Counter We can often find visitor counters in stadiums, malls, offices, and class rooms. What do they do with the lights when nobody is present? How do

they turn them on or off? Using Arduino Uno, we have developed an automatic light control project that also tallied visitors in the room in a bidirectional manner. There is a lot of fun and learning to be had with the project for hobbyists and students. Components Arduino UNO Relay (5v) Resisters IR Sensor module 16x2 LCD display Bread Board Connecting Wires Led BC547 Transistor This project uses Arduino to interface sensors, motors, and other components with a visitor counter. This counter can count people in both directions. You can use this circuit to count who enters a building, mall, home, or office. By incrementing the count when a person exits the hall, the number of persons left the hall can be counted. Sensors as well as gates of parking areas are examples of other public places where sensors can be used. And it depends on where they are placed in the mall/hall. Sensors, controllers, counter displays and gates comprise the four parts of this project. An interruption would be detected by the sensor, and its input would be used by the controller to increase or decrease the counter based on whether a person entered or exited. A 16x2 LCD screen displays the counting through the controller.

We set a delay for the other sensor so that it won't work if the IR sensor is interrupted by an object present in the room.

A visitor counter circuit consists of the following sections: sensors, controls, displays, and drivers. Sensor section: Two IR sensor modules with LED's, potentiometers, comparators (Op-Amps), and IR diodes were used in this chapter. Infrared sensors sense objects and cause a change in voltage at the comparator's second terminal. A potentiometer is used to measure voltage at the comparator's first terminal. This is then compared with the output voltage by the comparator and a digital signal resulted. Here in this circuit, two sensors are being compared using two comparators. A comparison is performed with LM358. LM358 has two Op-amps built into it. Control Section: Throughout the process of this visitor counter project, Arduino UNO is being utilized. A digital pin 14 and a digital pin 19 are connected to the outputs of comparators. A relay driver circuit drives a relay

by sending commands to Arduino from the LED control circuit. You can learn how to operate a relay with Arduino with this tutorial if you are having problems working with relay. Display section: A 16x2 LCD screen is provided in the display section. During this time the number of people will be counted and the lighting status will be shown. Suitable relay driver/section: The relay driver section consists of a BC547 transistor and a 5-volt relay used to control the light bulb. Since the Arduino will not supply enough current and voltage to operate the relay, a transistor is used instead. Our relay driver circuit was added to provide enough voltage and current to work the relay. This transistor drives a relay connected to the Arduino and turns the light on/off accordingly. Visitor Counter Circuit Diagram The pins 14 (A0) and 19 (A5) of the Arduino digital board interface directly with the outputs of IR sensors. At digital pin 2, there is a Relay driver transistor. A four-bit LCD is connected. In the LCD, the clock and data pins are connected directly to pins 13 and 12. A direct connection is made also between the Arduino D11-D8 and LCD pin D4-D7 respectively.

Additionally, this project can be equipped with a GSM modem so that the operation can be controlled remotely by SMS. This would allow the equipment to know the status and to be adjusted accordingly. Using simple microcontrollers to design an automatic room controller is the subject of this article. Therefore, it would be wise to implement this type of home automation system for energy savings.