What is it?

9Pcs of gas sensor module:

• 1 x MQ2
• 1 x MQ-3
• 1 x MQ-4
• 1 x MQ-5
• 1 x MQ-6
• 1 x MQ-7
• 1 x MQ-8
• 1 x MQ-9
• 1 x MQ-135

Very easy to use with only 4 pin (2.54mm pitch):

• Vcc (5V typic)
• GND
• Analog output: for direct ADC with microcontroller)
• Digital ouput (TTL 0-5V): for simple level detection (threshold can be changed thanks to the built-in potentiometer)

Module Features:

• power LED indicator
• TTL signal output LED indicator
• can be used as measurement (ADC) or direct level detection (adjustable threshold)
• four screw holes for easy positioning
• dimensions: ~32 x 22 x 27mm
• rapid response and recovery characteristics

Electrical properties:

• Input voltage: DC 5V
• Power consumption: 30mA to 200mA (according to the reference)

What can you measure with these sensors?

Various gas like:

• alcohol
• methane (CH4)
• benzine (C6H6)
• isobutane (C4H10)
• propane (C3H8)
• hexan (C6H14)
• LPG (C3H8)
• hydrogen (H2)
• carbon monoxide (CO)
• carbon dioxide (CO2)
• mono-nitrogen oxide NOx (NO and NO2)
• ammonia (NH3)
• cigarette smoke
• cooking fumes

(refer to the datasheet for more details of each sensors)

Why do I sell it?

I bought this kit few months ago for a personal project, but it doesn't match with my requirements. So I sell it to make some free space on my workshop.