MQ-135 Gas Sensor Air Quality

This sensor module records general air quality. The analog output AO provides the current sensor value and can be read directly by a microcontroller such as the Arduino Uno. The digital output DO switches as soon as the limit set with the potentiometer is reached. Without calibration, the sensor does not deliver ppm values. The module is not a gas warning device.

Recommended alternative for measuring CO2: SCD40 CO2 Sensor with Temperature and Humidity Sensor

Recommended alternative for VOC: Gravity SGP40 Air Quality Sensor

Recommended Accessories:

• Dupont Cable M-F 20cm 20 Pieces

Features:

• Sensor with heating element that gets warm in operation and requires 5 V
• Leave powered for a longer time before the first measurement, the sources state 24 to 48 hours
• Analog output: 0 to 5 V, so do not connect it directly to 3.3 V boards
• Digital output: LOW as soon as the limit is exceeded, the LED then lights up
• Limit adjustable with potentiometer on the module
• Arduino library MQ135 available

Application Examples:

• Monitoring indoor air quality
• Triggering a fan when the air is poor
• Detecting smoke and vapours in test setups

Documentation:

• MQ-135 with Arduino tutorial (Microcontrollers Lab)
• MQ-135 data and sample code (Keyestudio)
• MQ135 Library (GitHub)

Technical Data:

• Type: MQ135
• Module: marking Flying-Fish, comparator LM393
• Operating voltage: 5 V DC
• Operating current: 150 mA
• Heater power: 800 to 900 mW, depending on the datasheet
• Responds to: NH3, NOx, alcohol, benzene, smoke, CO2
• Digital output: TTL
• Analog output: analog
• Pins: AO, DO, GND, VCC
• Dimensions: 33 × 20.7 × 22 mm
• Weight: 7 g

Scope of Delivery:

• 1× MQ-135 gas sensor module