The MQ-2, manufactured by Zanefac (Part ID: MQ-2), is a versatile gas sensor designed to detect a variety of gases, including LPG, propane, methane, and smoke. It operates on the principle of resistive change when exposed to target gases, providing an analog output proportional to the gas concentration. This sensor is widely used in applications such as gas leak detection, air quality monitoring, and safety systems.
This circuit is a gas detection alarm system that uses an MQ2 gas sensor to detect gas levels. When gas is detected, the sensor outputs a signal that triggers a buzzer to sound an alarm. The circuit is powered by a 2 x AA battery mount.
Open Project in Cirkit Designer
This is a simple gas detection alarm system that uses an MQ-2 sensor to detect gas presence and sound a buzzer when gas is detected. It is powered by a rechargeable 18650 battery, with a TP4056 module for battery management and charging. A rocker switch is used to control the power to the system.
Open Project in Cirkit Designer
This circuit is an automated safety system that detects smoke or gas using an MQ2 sensor and activates a solenoid lock and buzzer in response. It includes a voice recognition module, an ESP32 for additional functionalities, and is powered by a 12V battery and solar panel with a charge controller. The system is controlled by an Arduino Mega 2560, which also manages multiple relays to control exhaust fans and other components.
Open Project in Cirkit Designer
This circuit is designed for an automatic safety and alert system that detects smoke or gas using an MQ2 sensor, and in response, unlocks a solenoid lock and activates a buzzer. It features an Arduino Mega 2560 for control logic, a DFPlayer Mini for audio output, a voice recognition module for voice commands, and an ESP32 for additional functionalities. The system is powered by a 12V battery, supported by a solar panel through a charge controller, and uses relays to control exhaust fans.
Open Project in Cirkit DesignerThe MQ-2 sensor is designed for ease of use and integration into various electronic systems. Below are its key technical details:
| Parameter | Value |
|---|---|
| Operating Voltage | 5V DC |
| Load Resistance (RL) | Adjustable (typically 10 kΩ) |
| Heater Voltage (VH) | 5V ± 0.2V |
| Heater Power Consumption | ≤ 800 mW |
| Detection Range | 200 ppm – 10,000 ppm |
| Preheat Time | ≥ 24 hours for stable output |
| Output Signal | Analog (voltage proportional to gas concentration) |
| Operating Temperature | -20°C to 50°C |
| Humidity Range | 35% – 95% RH |
| Response Time | ≤ 10 seconds |
| Recovery Time | ≤ 30 seconds |
The MQ-2 sensor typically comes with four pins or terminals. Below is the pinout description:
| Pin Name | Description |
|---|---|
| VCC | Power supply pin (5V DC) |
| GND | Ground pin |
| AOUT | Analog output pin (provides gas concentration) |
| DOUT | Digital output pin (threshold-based signal) |
The MQ-2 sensor is straightforward to use in a circuit. Follow the steps below to integrate it into your project:
VCC pin to a 5V DC power source and the GND pin to ground.AOUT pin to an analog input pin of your microcontroller (e.g., Arduino UNO) to read gas concentration levels.DOUT pin to a digital input pin of your microcontroller. Use the onboard potentiometer to set the gas concentration threshold for triggering the digital output.Below is an example code snippet to interface the MQ-2 sensor with an Arduino UNO and read the analog output:
// MQ-2 Gas Sensor Example Code
// Manufacturer: Zanefac
// Part ID: MQ-2
// This code reads the analog output of the MQ-2 sensor and prints the value to the Serial Monitor.
const int analogPin = A0; // Connect AOUT pin of MQ-2 to Arduino analog pin A0
int sensorValue = 0; // Variable to store the sensor reading
void setup() {
Serial.begin(9600); // Initialize serial communication at 9600 baud
Serial.println("MQ-2 Gas Sensor Test");
}
void loop() {
sensorValue = analogRead(analogPin); // Read the analog value from the sensor
Serial.print("Gas Concentration (Analog Value): ");
Serial.println(sensorValue); // Print the sensor value to the Serial Monitor
delay(1000); // Wait for 1 second before the next reading
}
No Output or Incorrect Readings:
Fluctuating Readings:
Digital Output Not Triggering:
Q1: Can the MQ-2 detect multiple gases simultaneously?
A1: Yes, the MQ-2 can detect multiple gases such as LPG, propane, methane, and smoke. However, it does not differentiate between them; it provides a combined analog output based on the total gas concentration.
Q2: How do I calibrate the MQ-2 sensor?
A2: To calibrate, expose the sensor to clean air and record the baseline analog output. Use this value as a reference for detecting gas concentrations.
Q3: Can the MQ-2 be used outdoors?
A3: The MQ-2 is not designed for outdoor use as it may be affected by extreme temperatures, humidity, and environmental contaminants. Use it in controlled indoor environments for best results.
Q4: What is the lifespan of the MQ-2 sensor?
A4: The typical lifespan of the MQ-2 sensor is around 2–3 years under normal operating conditions. Regular maintenance can help extend its life.
By following this documentation, users can effectively integrate and utilize the MQ-2 gas sensor in their projects.