An Overview about MQ9 Sensor
The MQ9 is a methane, carbon monoxide gas detection sensor. The sensor includes tin dioxide as its sensing element. The SnO2 (tin dioxide)has lower conductivity in pure air. When the air has carbon Monoxide, Coal, Liquefied, flammable gases, the conductivity of the sensor gets higher. A simple device makes measuring this change in conductivity and turning it into obvious data. However, the sensor requires some calibration.
Calibration
Before using the module, one must have to calibrate this sensor. This sensor estimates the flammable gas concentration using a resistance ratio. This ratio includes Maximum sensor resistance in 1000ppm R0 and internal resistance Rs. In pure air, after preheating, you need to upload the calibration code and wait for fifteen minutes until R0 reaches a fixed value.
Working Principle
When the air has Carbon Monoxide, Coal, Liquefied, Combustible Gas Sensor, the resistance of the sensor decreases. Hence, the output from the Gas sensor varies when the concentration of gas increases. We can adjust the sensitivity by adjusting the potentiometer.
Features and Specifications of MQ9 Sensor
There are many prominent features and specification of MQ-9 which makes it more extraordinary
Features
- Good sensitivity to CO/Combustible Gas
- High sensitivity to Methane, Propane, and CO
- Long life, stable and low cost
- Simple drive circuit
Specifications
- Operating Voltage is +5V
- Heating consumption: 0.5-340mW
- Adjustable Load resistance
- Heater Resistance: 33Ω±5%
- Minimum detecting Concentration: 200ppm
- Maximum Detecting Concentration: 1000/10000/10000ppm
Pinout of MQ9
| Pin Number | Pin Name | Description |
| 1 | Vcc | The [in is there to power the module, requires 5V |
| 2 | Ground | To connect the module to the system’s common ground |
| 3 | Digital Out | Digital output pin, the Threshold value can be set by using the potentiometer |
| 4 | Analog Out | Analog output pin. Analog voltage based on the concentration of the gas |
Applications of MQ9 Sensor
Domestic Gas Leakage
The goal of detecting a gas leak is to prevent the worst potential causes of the gas leak, using the above type of MQ sensor. The choice of the MQ9 sensor is because of MQ9 which is suitable for detecting natural gas.
Industrial Gas Detector
The environmental, industrial gas detector can provide a suitable monitoring method that uses an MQ9 sensor. This is a lightweight, customer-friendly, and low-cost air monitoring device that can measure Methane gas we can use for safety purposes in industries.
