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Smoke detector using MQ-2 Gas sensor

In this tutorial, we will see how to make a smoke detector that will help prevent smoking in public areas.

Smoking is extremely hazardous to health. Even in the smoking areas, people intend to smoke. This passive smoke is unhealthy for other surrounding people. That’s why I have developed a smoke detector for no-smoking zones. A pair of these devices can be installed in the no-smoking zones of hotels, hospitals, malls, etc.

Working of the circuit: The working of the circuit is pretty simple. When the MQ-2 gas sensor senses smoke and the value of the smoke goes beyond 150, the Arduino will be signaled to buzz the buzzer and a cross will appear on the Matrix dot display. So, when a person starts smoking in a no-smoking zone, the surrounding people will be alarmed.

First of all, we need to learn in detail about each component and the working of the circuit. Components are as follows:

1) MQ-2 Gas sensor: MQ2 gas sensor is an electronic sensor used for detecting the concentration of gases in the air. This sensor contains a sensing material whose resistance changes when it comes in contact with the gas. This change in the value of resistance is used for the detection of gas. It has four pins namely, Gnd, Vcc, AO (Analog output), and DO (Digital Output). The pinout diagram of this sensor is shown below.

Note: In this project, I am using an 8x8 matrix display module (MAX7219).

2) Matrix dot display (MAX7219): A matrix dot display is an electronic device that uses a patterned led array to display numbers, alphabets, graphics, etc. The display has five pins CLK, CS, DIN, GND, and Vcc. The pinout diagram of the MAX719 is given below.”

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