In this project, we'll use NodeMCU ESP8266 and Ubidots MQTT to make an IR-based, two-way visitor counter that works with IoT. You can use Ubidots Dashboard to keep track of how many people are coming to, leaving, and staying on your site from anywhere in the world. Use an Infrared or IR Sensor to keep track of how many people are coming and going. The NodeMCU ESP8266 WiFi Module automatically sends the data about visitors to Ubidot's cloud. This NodeMCU Bidirectional Visitor counter can be used to count the number of people who come into a room, office, shopping mall, or event at the front gate. The device counts how many people come in and out of the gate. It also counts how many people leave through the different gates. And finally, it figures out how many people are currently online by subtracting the number of people who left from the number of people who came in. If

there is even one person in the room, the light will turn on by itself. When no one is in the room, the light automatically turns off. In one of my past projects, I used Arduino to make the Visitor Counter Project. But this time, instead of watching the data on an OLED screen, we will send it to the cloud. We can use an ESP8266 Wifi Module, a pair of IR Sensors, an OLED Display, and a Relay Module to make this IoT Visitor Counter. Aside from these main parts, we also need a PCB Board and some passive electronic parts. The project is so simple that even a newbie can do it with no trouble. IR Sensor as Visitor Detector The IR sensor, which works as an obstacle detector, is the most important part of this IoT project. When the IR sensor sees a person, it counts them and adds them to the total from before. The IR Sensor module is very good at adapting to the light around it. It has a sender and a receiver for infrared. The infrared emitting tube sends out a certain frequency, which gets reflected back to the signal when it hits something. The receiver tube then gets the signal that was sent back.

Opamp, a variable resistor, and an output LED are the other parts of the circuit. The Sensor consists of the following electronics components. 1. IR LED Transmitter IR LED emits light, in the range of Infrared frequency with a wavelength of 700nm – 1mm. IR LEDs send out light at an angle of about 20 to 60 degrees and can reach up to 5 to 10 cm away.

2. Photodiode Receiver The photodiode is the IR receiver because it conducts electricity when light hits it. The outside of a photodiode is black, making it look like an LED. 3. LM358 Opamp Operational Amplifier (Op-Amp) LM358 is used in the IR sensor as a voltage comparator. The comparator circuit checks the difference between the voltage set by the preset and the voltage of the photodiode's series resistor. When the voltage drop across the Photodiode's series resistor is more than the threshold voltage, the Op-output Amp's is high, and vice versa. When the Op-Amp output is high, the LED at the output terminal lights up. This means that an object has been found. 4. Variable Resistor In this case, the variable resistor is set. It is used to set the range of distances where the object should be picked up. IoT Two-Way Visitor Counter Schematic or Circuit

The Circuit for NodeMCU ESP8266 Bidirectional Visitor Counter is very easy to understand. Here is a diagram of how the project will work. You can use Fritzing Software to make the schematic. Connect the 0.96" OLED Display's I2C pins (SDA and SCL) to the NodeMCU's D2 and D1 pins. Connect the IR sensors' output pins to NodeMCU's D5 and D6. One of the IR sensors will count how many people come in, and the other will count how many people leave. Connect a 5V Relay Module to NodeMCU's D4 Pin in the same way. At 5V VCC, both the IR Sensors and the Relay Module work. You can get 5V from the Vin pin on the Amica NodeMCU or the VU pin on the Lolin NodeMCU. Schematic & PCB Designing

You can put this circuit together and test it on a breadboard. But if you don't want to put the circuit together on a breadboard, you can look at this schematic and make a custom PCB. For drawing the Schematic, I like to use EasyEDA, which is an online Schematic & PCB Designing Tool.