Detect Gas Changes with a Practical Air Sensor

The Gas Sensor MQ135 is a gas sensor with uart designed for air-quality projects, leak alerts, and ventilation monitoring. It is a practical fit for makers, students, and engineers who want reliable sensor data in embedded builds.

Key details include Working voltage: DC 5V; Interface: UART.

Important: Most gas and chemical sensors work best after warm-up and calibration. Readings can drift with temperature, humidity, and sensor age.

Why you’ll love it

Power range: DC 5V
Current draw: 150mA
Useful spec: TTL output
Compact size: 32mm x 22m x 27mm(HIGH 27mm)
Easy wiring: UART
Maker-friendly build: Easy to use in prototypes, classroom projects, and custom electronics

Compare with similar products

Product	Sensor style	Standout
Gas Sensor MQ135	gas sensor with UART	Current item
Gas Sensor MQ5 Analog LPG For Arduino	gas sensor with analog output	analog output, digital output
Gas Analog Smoke LPG CO Sensor MQ2	gas sensor with analog and digital output	adjustable sensing range, analog output
Gas CO Combustible Analog Sensor MQ9 For Arduino Gravity	gas sensor with analog output	analog output, gas detection

What you can build

This sensor is a good fit for gas leak alarms, indoor air monitors, safety demos, ventilation control, and science projects.

Starter bundles

Pair it with an Arduino-compatible board, ESP32, or Raspberry Pi, plus a breadboard or jumper wires for quick setup and testing.

Recommended add-ons

Useful add-ons include fresh-air test setup, an enclosure with vents, and a display for local readout, depending on how you plan to power, mount, and log the sensor.

Technical specifications

Product	Gas Sensor MQ135
Working voltage	DC 5V
Working Current	150mA
DOUT	TTL output
AOUT	Analog output
Dimension	32mm x 22m x 27mm(HIGH 27mm)
Preheat time	Over 20s
Interface	UART

Wiring & usage notes

Connect power and ground, then wire TX and RX to a serial-capable controller at the correct logic level and baud rate. Most gas and chemical sensors work best after warm-up and calibration. Readings can drift with temperature, humidity, and sensor age.

What’s in the box

1 × Gas Sensor MQ135

Frequently Asked Questions

What does the Gas Sensor MQ135 measure? It is designed to measure gas concentration changes in air.

Can I use it with Arduino, ESP32, or Raspberry Pi? Yes. It is well suited for common maker and embedded platforms, as long as you power it at the correct voltage and match the signal level to your controller.

How do I connect this UART sensor? This version uses UART or serial output, so you connect power plus TX and RX at the correct logic level.

Does it need calibration? Yes. Chemical and gas sensors usually need warm-up time, calibration, and periodic checking if you want stable readings.

Is it good for prototyping? Yes. It is a practical choice for learning, proof-of-concept builds, and small automation projects.