MQ135
MQ-135 air quality sensor module for detecting harmful gases in air. Opencircuit lists analog output plus adjustable digital threshold output, 5±0.2V warm-up voltage, 150mA warm-up current, and 300–5000ppm detection range.
Pinout
- VCC
5V module supply. Opencircuit lists 5±0.2V warm-up voltage and 150mA warm-up current.
Type · PowerVoltage · 5 - GND
Common ground.
Type · Ground - AOUT
Analog gas concentration output.
Type · Analog - DOUT
Comparator digital output with adjustable trigger concentration.
Type · GPIO
| Pin | Type | Function | Voltage |
|---|---|---|---|
| VCC | Power | 5V module supply. Opencircuit lists 5±0.2V warm-up voltage and 150mA warm-up current. | 5 |
| GND | Ground | Common ground. | |
| AOUT | Analog | Analog gas concentration output. | |
| DOUT | GPIO | Comparator digital output with adjustable trigger concentration. |
Pin details
4 connections- VCC
5V module supply. Opencircuit lists 5±0.2V warm-up voltage and 150mA warm-up current.
PowerVoltage · 5 - GND
Common ground.
Ground - AOUT
Analog gas concentration output.
Analog - DOUT
Comparator digital output with adjustable trigger concentration.
GPIO
Start wiring
I2C · Analog · UART · 3.3 – 5 V · Breakout
Waveshare lists MQ-2 for combustible gases and smoke, MQ-3 for alcohol, and MQ-135 for mixed indoor pollutants such as NH3, NOx, alcohol,…
Module pins: VCC, GND, AOUT, DOUT. Schematik maps them to your board in the app.
Air quality
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