MQ-9 Gas Sensor Module | Carbon Monoxide, Methane, and LPG Detector

The MQ-9 Gas Sensor Module detects Carbon Monoxide (CO), Methane (CH4), and LPG (Liquefied Petroleum Gas) using a heated metal oxide sensing element that changes electrical resistance when target gases are present. The mq 9 sensor outputs both an analog voltage signal and a TTL (Transistor-Transistor Logic) digital output that switches cleanly at a set threshold. It runs on 5V DC and draws 150mA, mainly for the internal heater.

A non-obvious detail about the mq9 gas sensor is that the sensing element needs a preheat (warm-up) time of around 20 to 48 hours before giving stable readings after being stored unused. The honest limitation is cross-sensitivity — the mq 9 gas sensor datasheet confirms it also reacts to alcohol vapour, which can cause false alarms in kitchen environments. The module works with Arduino IDE using analogRead or a simple digitalRead. Get it from StemVolt with fast delivery across India.

Related Products:

• Checkout The MQ-7 Gas Sensor Module

Features:

• Detectable gases include Carbon Monoxide, Methane CH4, and LPG for multi-gas safety coverage.
• 5V DC operating voltage and 150mA current draw requires a dedicated stable power supply.
• TTL digital output at 0.1V LOW and 5V HIGH gives a clean microcontroller-compatible alarm signal.
• Module dimensions of 32 x 20 x 16mm allow mounting inside standard project enclosure cutouts.

Technical specifications:

Applications

• Kitchen safety alarm project uses this sensor to detect LPG leaks and sound a buzzer.
• MQ-9 Gas Sensor Module reads analog concentration values and sends SMS alerts over a GSM module.
• lpg gas detector project reads TTL output and triggers a relay to cut the LPG supply automatically.

Package includes:

• 1 x MQ-9 Gas Sensor Module