The gas-sensitive material used in the MO gas sensor is tin dioxide (SnO₂), which has low conductivity in clean air. When combustible gases are present in the sensor's environment, the conductivity of the sensor increases with the concentration of the combustible gas in the air. Using a simple circuit, the change in conductivity can be converted into an output signal corresponding to the gas concentration. The MO gas sensor exhibits high sensitivity to sensitive gases such as liquefied petroleum gas, propane, and hydrogen, and is also ideal for detecting natural gas and other combustible vapors. This sensor can detect a variety of combustible gases and is a low-cost sensor suitable for a wide range of applications.

Component external structure

Product Features
1.Utilizes a high-quality double-sided board design with power indication and TTL signal output indication.
2.Features both DO switch signal (TTL) output and A0 analog signal output.
3.The TTL output active signal is low level (the signal light turns on when the output is low, and it can be directly connected to a microcontroller or relay module).
4.The analog output voltage increases with higher gas concentration.
5.Exhibits high sensitivity to methane and natural gas detection.
6.Equipped with four screw holes for easy positioning.
7.Product dimensions: 32 (L) × 20 (W) × 22 (H) mm.
8.Offers long service life and reliable stability.
9.Provides fast response and recovery characteristics.

Product Performance
Input Voltage: DC 5V
Power Consumption (Current): 150 mA
DO Output: TTL Digital Signals 0 and 1 (0.1 V and 5 V)
AO Output: 0.1–0.3 V (relative to no pollution), approximately 4 V at high concentration

Friendly Reminder: After the sensor is powered on, it requires a warm-up period of about 1 minute for the measurement data to stabilize. The sensor heating up is a normal phenomenon due to the internal heating wire. However, if it becomes too hot to touch, this is abnormal.

To connect the smoke sensor module, link its VCC and GND pins to the 5V and GND pins of the development board, respectively. Connect the AO pin of the module to the analog pin A0 of the development board, and the DO pin to digital pin 2 of the development board.

The schematic diagram of the experiment is shown below:

MQ-2 Smoke Sensor Module

Parameters:

• Input Voltage: DC 5V

• Power Consumption (Current): 150mA

• DO Output: TTL digital signal 0 and 1 (0.1V and 5V)

• AO Output: 0.1-0.3V (relative to no pollution), high concentration voltage around 4V

Features:

1. High-quality double-sided PCB design with power indicator and TTL signal output indicator.

2. Equipped with DO TTL switch signal output and AO analog signal output.

3. TTL output active signal is low level (signal light turns on when output is low, can be directly connected to a microcontroller or relay module).

4. Analog output voltage increases with higher gas concentration.

5. High sensitivity to liquefied gas, natural gas, city gas, and smoke.

6. Four screw holes for easy mounting.

7. Long service life and reliable stability.

8. Fast response and recovery characteristics.

Wiring:

• VCC: Connect to power supply positive (5V).

• GND: Connect to power supply negative.

• DO: TTL switch signal output.

• AO: Analog signal output.

MQ-3 Alcohol Sensor Module

Features:

1. High-quality double-sided PCB design with power indicator and TTL signal output indicator.

2. Equipped with DO switch signal (TTL) output and AO analog signal output.

3. TTL output active signal is low level (signal light turns on when output is low, can be directly connected to a microcontroller or relay module).

4. Analog output voltage increases with higher alcohol concentration.

5. High sensitivity to alcohol detection.

6. Long service life and reliable stability.

7. Fast response and recovery characteristics.

Parameters:

• Input Voltage: DC 5V

• Power Consumption (Current): 150mA

• DO Output: TTL digital signal 0 and 1 (0.1V and 3.3V)

• AO Output: 0.1-0.3V (relative to no pollution), high concentration voltage around 4V

Wiring:

1. VCC: Connect to power supply positive (5V).

2. GND: Connect to power supply negative.

3. DO: TTL switch signal output.

4. AO: Analog signal output.

MQ-4 Natural Gas Sensor Module

Features:

1. High-quality double-sided PCB design with power indicator and TTL signal output indicator.

2. Equipped with DO switch signal (TTL) output and AO analog signal output.

3. TTL active output signal is low level (signal light turns on when output is low, can be directly connected to a microcontroller or relay module).

4. Analog output voltage increases with higher gas concentration.

5. High sensitivity to methane and natural gas detection.

6. Long service life and reliable stability.

7. Fast response and recovery characteristics.

Parameters:

• Input Voltage: DC 5V

• Power Consumption (Current): 150mA

• DO Output: TTL digital signal 0 and 1 (0.1V and 5V)

• AO Output: 0.1-0.3V (relative to no pollution), high concentration voltage around 4V

MQ-5 Liquefied Petroleum Gas Sensor Module

Features:

1. High-quality double-sided PCB design with power indicator and TTL signal output indicator.

2. Equipped with DO switch signal (TTL) output and AO analog signal output.

3. TTL active output signal is low level (signal light turns on when output is low, can be directly connected to microcontroller or relay module).

4. Analog output voltage increases with higher gas concentration.

5. High sensitivity to coal gas and natural gas detection.

6. Long service life and reliable stability.

7. Fast response and recovery characteristics.

Parameters:

• Input Voltage: DC 5V

• Power Consumption (Current): 150mA

• DO Output: TTL digital signal 0 and 1 (0.1V and 5V)

• AO Output: 0.1-0.3V (relative to no pollution), high concentration voltage around 4V

MQ-6 Propane Gas Sensor Module

Features:

1. Premium double-layer PCB design with power indicator and TTL signal output indicator

2. Features DO digital switch output (TTL) and AO analog signal output

3. Active-low TTL output (signal LED illuminates at low level, compatible with MCUs and relay modules)

4. Analog voltage output (0-5V) proportional to gas concentration

5. High sensitivity to propane, butane, LPG and LNG detection

6. Extended operational lifespan with reliable stability

7. Rapid response and recovery characteristics

Specifications:

• Operating Voltage: DC 5V

• Current Consumption: 150mA

• DO Output: TTL digital signal (0.1V and 5V)

• AO Output: 0.1-0.3V (ambient level), up to ~4V at high concentrations

MQ-7 Carbon Monoxide Sensor Module

Key Features:

1. High-quality dual-layer PCB design with power indicator and TTL signal output indicator

2. Provides both digital (DO) TTL output and analog (AO) voltage output

3. Active-low TTL logic (signal LED illuminates when output is low, compatible with MCUs and relay modules)

4. Analog output voltage increases proportionally with gas concentration

5. Optimized sensitivity for carbon monoxide (CO) detection

6. Long operational lifespan with stable performance

7. Fast response and recovery times

Technical Specifications:

• Operating Voltage: DC 5V ±10%

• Current Consumption: 150mA (typical)

• Digital Output (DO): TTL compatible (0.1V low / 5V high)

• Analog Output (AO): 0.1-0.3V (clean air), up to ~4V at high concentrations

MQ-8 Hydrogen Gas Sensor Module

Description:

1. Utilizes high-quality dual-panel design with power indicator and TTL signal output indicator.

2. Features a digital output (TTL) switch signal and an analog output signal.

3. The TTL output effective signal is low level. (When the output is low level, the signal light turns on, and it can be directly connected to a microcontroller or relay module.)

4. The analog output voltage increases with higher gas concentration.

5. Exhibits good sensitivity to hydrogen detection.

6. Offers long service life and reliable stability.

7. Provides fast response and recovery characteristics.

Specifications:

• Input Voltage: DC 5V

• Power Consumption (Current): 150mA

• Digital Output (DO): TTL digital signal 0 and 1 (0.1V and 5V)

• Analog Output (AO): 0.1–0.3V (relative to no pollution), high concentration voltage around 4V

MQ-9 Combustible Gas Sensor Module

Description:

1. Utilizes high-quality dual-panel design with power indicator and TTL signal output indicator.

2. Features a digital output (TTL) switch signal and an analog output signal.

3. The TTL output effective signal is low level. (When the output is low level, the signal light turns on, and it can be directly connected to a microcontroller or relay module.)

4. The analog output voltage increases with higher gas concentration.

5. Exhibits good sensitivity to carbon monoxide detection.

6. Offers long service life and reliable stability.

7. Provides fast response and recovery characteristics.

Specifications:

• Input Voltage: DC 5V

• Power Consumption (Current): 150mA

• Digital Output (DO): TTL digital signal 0 and 1 (0.1V and 5V)

• Analog Output (AO): 0.1–0.3V (relative to no pollution), high concentration voltage around 4V