Introduction: How to Make a LoT Smoke/Alcohol Detectors & Fire Alarms With NodeMCU ESP8266 Blynk DHT11, MQ-2, MQ-3

More details you can watch my Youtube Video.

Step 1: Parts List

The MQ-2 Gas sensor is suitable for detecting H2, LPG, CH4, CO, Alcohol, Smoke or Propane.

The MQ-3 Gas sensor is suitable for detecting Alcohol, Benzine, CH4, Hexane, LPG, CO.

Due to its high sensitivity and fast response time, measurement can be taken as soon as possible. The sensitivity of the sensor can be adjusted by potentiometer.

This project requires the following parts, otherwise it will not show the effect of this project



MQ-2/MQ-3 smoke sensor

DHT11 Temperature & Humidity sensor

20X4 I2C LCD

Jumper wires


Red Led

Green Led

Step 2: Circuit Diagram

Step 3: Blynk Setting

Download the mobile app named blynk, create a new project, and customize the project name. Select NodeMCU, CONNECTION TYPE -Wi-Fi in CHOOSE DEVICE, and click Create.

Step 4: Arduino Setting

1. Open File-Preferences, enter

in the input box of additional Boards Manger URLs, and click "OK".

2. Install the development board: Open Tools-Board-Board Manager. Enter ESP8266 in the search box of Board Manager and install it.

Step 5: MQ-2 Testing

Step 6: MQ-3 Testing

Step 7: The Sensor Can Be Replaced With MQ-2 MQ-3 MQ-4 MQ-5 MQ-6 MQ-7 MQ-8 MQ-9 MQ-135.