Keyestudio MQ-135 SnO2 Benzene Sulfide Air Quality Sensor module

The Keyestudio MQ-135 SnO2 Benzene Sulfide Air Quality Sensor module is a versatile semiconductor gas sensor designed to detect a wide range of harmful atmospheric pollutants. It is an ideal, cost-effective choice for South African makers, students, and hobbyists building environmental monitoring systems or smart home automation projects.

Tin dioxide sensing technology

The MQ-135 uses tin dioxide as its gas-sensitive material, which exhibits low electrical conductivity in clean air. When exposed to polluted air, its conductivity increases in proportion to the concentration of pollutants, allowing for an accurate, convertible output signal.

Broad harmful gas detection

This sensor offers high sensitivity to a variety of hazardous substances, including ammonia, sulfide, benzene vapour, and smoke. This broad detection capability makes it highly suitable for multi-purpose air quality monitoring applications.

Target gases and packaging

Specifically calibrated to detect target gases such as ammonia, methylbenzene, and hydrogen, the semiconductor sensor is housed in a durable black bakelite package.

Adjustable load resistance

The module features an adjustable load resistance alongside a standard loop voltage of up to 24V DC. This allows users to fine-tune the sensor circuit for precise environmental measurements.

Heater power and resistance

The integrated heater operates on an AC or DC voltage of 5.0V with a power consumption of 900mW or less. The internal heating resistor measures 31 ohms at room temperature.

Sensitivity and preheating requirements

To ensure stable and reliable readings, the sensor requires a preheating time of 48 hours or more before initial use. It features a surface resistance of 2K to 20K ohms in 100ppm of ammonia, with a sensitivity ratio of 5 or greater.