IoT Based Air Pollution & Gas Sensor Values Detection

Abstract: In this project we are going to use MQ-02 Sensor module to to detect the values of smoke and LPG in the air. This sensor module utilizes an MQ-02 as the sensitive component and has a protection resistor and also adjustable resistor on board. The MQ-02 sensor is sensitive to LPG, i-butane, propane, methane, alcohol, hydrogen and smoke. The resistance of the sensor changes as the concentration of the gas changes.

Download PowerPoint Presentation Here

Server: In this project, we are sending the reading of sensor to the Android Application through the Google Firebase Database. Firebase is a mobile and web development platform developed by Firebase, inc in 2011. The real time database shows the data in real time in app.

Firebase Database

MQ-02 Sensor: The protection resistor (4.7Kohms) and the adjustable (0-50Kohms) are in serial which forms a load resistor R_L (4.7-54.7Kohms). The sensor’s resistance R_S and R_L forms a voltage divider. The output voltage on the signal pin could be read by Arduino or MCU via ADC.  Given a value of R_L , Power Supply Voltage, and output voltage, R_S could be derived.  Based on the chart provided in the MQ-2 datasheet, R_S in clean air under given temperature and humidity is a constant，which is the “initial” resistance of the sensor named R_O. R_O of the resistor could be derived from R_S. The main job of the calibration is to calculate the R_O by sampling and averaging the readings when the module is placed in the clean air. Once the R_O is derived, the concentration of target gas could be calculated by using the R_S/R_O ratio as the input. To achieve more accuracy, a segmented look-up table should be used. However, in the demonstration, a linear formula is used as an approximation to the original curve.

Download MQ-02 Datasheet Here 

Components:

1. NodeMCU
2. BreadBoard
3. MQ-02 Sensor
4. USB Cable
5. Connecting Wires  

Connections:

1. Connect Vcc of sensor to Vin of NodeMCU
2. Connect GND to GND
3. Connect A0 of sensor to A0 of NodeMCU

Code:
1. NodeMCU Code (Arduino IDE)
Download Code Here 

2. Android Application Code
Note: Check out 'PollutionDetector' module from project named 'Vprojetcs'
here is the link:
https://github.com/vikrammore246/VProjetcs


Check Out The Video:

Project Details:

Project by:
Vikram K. More
Amravati,Maharashtra.

Project done @ImbueDesk Internship as IoT Engineer.

ImbueDesk UID:
IOOC0303