MQ135 Air Quality Sensor

Overview

This module interfaces with the MQ135, They are used in air quality control equipments for buildings/offices, are suitable for detecting of NH3,NOx, alcohol, Benzene, smoke, CO2, etc. Support is included in the MQ135 (About Modules) module.

Key Specifications:

Voltage	5V
Consumption	< 800mW
Preheat time	over 24h

Note that the "warning-up" time of this class of Sensor is over 24 hours to get trusted data.

Wiring

Device Pin	Espruino
1 (Vcc)	VBat (5V)
2 (DOUT)	N/C
3 (AOUT)	A7*
4 (GND)	GND

*You can use any GPIO with ADC support. See in board pin references

Usage

call require("MQ135").connect(pin) to get a MQ135 object. Take use of this object call getPPM method

For example:

  var mq = require("MQ135").connect(A7);
  console.log(mq.getPPM());

You can also use the ambient temperature/humidity correction factor:

For example:

  var mq = require("MQ135").connect(A7);
  var temperature = 25;
  var humidity = 80;
  console.log(mq.getCorrectedPPM(temperature, humidity));

Its recommended to get this ambient data to get more precise PPM value. You can use DHT11 Espruino Module for this propose.

Buying

MQ135 parts and modules can be purchased from many places:

• eBay

Reference

• Technical Data