How MQ2 Gas Sensor works ? | 3D Animated 🔥

0:00 Ever wondered how to make your Arduino smell what's in the air? With the MQ2 gas sensor module, you can give your project a virtual nose capable of detecting a wide range of gases, including LPG, smoke, alcohol, propane, hydrogen, methane, and even carbon monoxide. In this video, we'll explore how this amazing sensor works, how to hook it up to your Arduino. So, without wasting any time, let's get started. The MQ2 sensor is one of the most popular sensors in the MQ family. It is a type of MOS, metal oxide semiconductor sensor. These kinds of sensors are also called chem resistors because they work by changing their electrical resistance

0:46 when they come into contact with certain gases. The MQ2 gas sensor runs on 5 volts of DC power and uses about 800 mWs of energy. It can detect several types of gases, including LPG, liqufied petroleum gas, smoke alcohol propane hydrogen methane, and carbon monoxide. This sensor can detect these gases when their concentrations are between 200 and 10,000 parts per million, ppm. The MQ2 is a heaterdriven sensor, which means it uses heat to detect gases. Because it deals with flammable gases, safety is very important. That's why the sensor has two layers of very fine stainless steel mesh wrapped around

1:32 it known as an anti-exlosion network. This mesh prevents the heater inside the sensor from causing a fire or explosion if flammable gases are present. Besides providing safety, this mesh also acts as a protective filter. It blocks dust and solid particles from entering, allowing only gases to pass through to the sensing area. The mesh is held firmly in place by a copper plated ring that clamps around it and connects to the rest of the sensor body. If you carefully remove the outer mesh, you can see the inside of the sensor. At its heart is a sensing element attached to six metal legs that stick out from a round base made of bely, a type of hard plastic. These legs are arranged in a star pattern. Out of the six legs, two of them labeled H are

2:20 used to heat up the sensing element. These two legs are connected by a coil made of nickel chromium alloy. This special metal mixture is good at conducting electricity and can withstand very high temperatures without melting or breaking down. The other four legs labeled A and B are responsible for carrying electrical signals from the sensing element to external electronics. These connect to the sensing element using platinum wires. Platinum is used due to its excellent electrical conductivity and sensitivity to small electrical changes that happen when gas levels change around the sensor. The sensing element itself looks like a small tube. It's made from aluminum oxide ceramic with a thin coating of tin dioxide on it. Tin dioxide is the key material here

3:07 because it reacts chemically with flammable gases causing changes in resistance that the sensor can measure. The ceramic base serves an important purpose too. It ensures even distribution of heat and maintains the sensor at the proper operating temperature. How does a gas sensor work? When you turn on an MQ2 gas sensor, it starts heating up its internal tin dioxide semiconductor layer to a high temperature. At this high temperature, oxygen molecules from the air stick to the surface of the tin dioxide. These absorbed oxygen molecules pull free electrons away from the tin dioxide, which creates an electron depletion region near the surface. This makes the tin dioxide highly resistant to electrical flow. So only a small amount

3:52 of electric current can pass through it. When combustible gases enter the sensor, they react with the oxygen molecules that are stuck to the tin dioxide surface. This chemical reaction releases the electrons that were being held by the oxygen. As these electrons return to the tin dioxide, the electron depletion region gets smaller. This reduces the resistance, allowing electricity to flow much more easily through the sensor. The MQ2 sensor works by detecting these changes in electrical resistance. The more flammable gas there is, the more oxygen molecules react and the more the resistance decreases. This makes it easier for microcontrollers connected to the sensor to detect both the presence and the concentration of gas in the air.

4:39 The analog output from the AO pin changes based on the concentration of gas. When there's more gas in the air, the output voltage increases. When there's less gas, the output voltage decreases. The animation below demonstrates this relationship between gas concentration and output voltage. This analog signal also goes to the LM393 comparator, which compares it to a reference voltage set by a potentiometer on the module. When the gas concentration rises above your set level, the comparator outputs a low digital signal at the digital pin DO. When the gas concentration stays below your set level, it outputs a high digital signal instead. You can use this digital output

5:26 to trigger actions like sounding an alarm or sending an alert to your phone. The module also has two indicator LEDs. The power LED lights up when the module receives power. The status LED lights up when the gas concentration exceeds the threshold you've set. Let's see the pin out of MQ2 gas sensor. VCC provides power to the sensor. Connect it to the 5V output on your Arduino. G&D is the ground pin. AO analog output gives a variable voltage that corresponds to the concentration of gas. DU digital output outputs a low signal when the gas concentration is above the threshold set by the potentiometer and a high signal

6:13 when it's below. Wiring MQ2 gas sensor to Arduino connections are shown in the image. So, I hope you have learned something new today. Make sure to hit that like and subscribe button for more informative videos. Thanks for watching.