Grove - Multichannel Gas Sensor

What is it?

Grove – Multichannel Gas sensor is a environment detecting sensor with a built in MiCS-6814 which can detect many unhealthful gases, and three gases can be measured simultaneously due to its multi channels, so it can help you to monitor the concentration which more than one gas.

This sensor is belong to Grove system, and you can plug it onto the Base shield and work with Arduino directly without any jumper wires. The interface of it is I2C, so plug it onto the I2C port of Base shield, then you can start to work it.

Note that The sensor value only reflects the approximated trend of gas concentration in a permissible error range, it DOES NOT represent the exact gas concentration. The detection of certain components in the air usually requires a more precise and costly instrument, which cannot be done with a single gas sensor. If your project is aimed at obtaining the gas concentration at a very precise level, then we do not recommend this gas sensor.

Before usage

Related Reading

We suggest you to read those knowledge before using the Gas sensor, it'll help you to learn more about Arduino and our products, and also it'll let you to use open souse hardware more easier.

After reading that you will know how to use Base shield with Grove products to work well with Arduino. Let's start it !

To be prepared

This tutorial will include some necessary products:

Hardware Overview

Four pins are pointed out and following is the figure
Pin Label Description
GND Connect to ground
VCC Power supply: 3.3v - 5v
SDA I2C data
SCL I2C clock

The power supply is between 3.3v and 5v, so this sensor can be compatible with a micro-controller whose output voltage is 3.3v.


Block Diagram

Electrical Characteristics

Item Condition Min. Typ. Max. Unit
Voltage - 3.1 3.3 5.25 V
Ripple @Max Power - 80 100 mV
Heating Power - - - 88 mW
Max Power - - - 150 mW
ADC Precision - - 10 - Bits
I2C Rate - - 100 400 kHz
VIL @I2C -0.5 - 0.99 V
VIH @I2C 2.31 - 5.25 V

Performance RED sensor

Characteristic RED sensor Symbol Typ Min Max Unit
Sensing resistance in air R0 - 100 1500
Typical CO detection range FS - 1 1000 ppm
Sensitivity factor SR - 1.2 50 -

Performance OX sensor

Characteristic OX sensor Symbol Typ Min Max Unit
Sensing resistance in air R0 - 0.8 20
Typical NO2 detection range FS - 0.05 10 ppm
Sensitivity factor SR - 2 - -

Performance NH3 sensor

Characteristic NH3 sensor Symbol Typ Min Max Unit
Sensing resistance in air R0 - 10 1500
Typical NH3 detection range FS - 1 300 ppm
Sensitivity factor SR - 1.5 15 -

Firmware and library


This grove module has an ATMega168 MCU which is flashed with a factory firmware. The firmware does the following works:

  1. controls the power on and off for heating circuit and indicator LED
  2. listens on the command that make the module do the calibration - the calibration will sample the resistance of the MEMS core of this sensor which will be used as the reference, so please perform calibration in a fresh air condition
  3. listens on commands that get resistance value of one of the three sensor core which will be used to calculate the concentration of a specific gas
  4. listens on the command that changing the I2C address of this module - at most time, you don't need to do this except that the I2C address of this module (0x04) conflicts with another slave module.

Note: the calibration has been done before the modules leave the factory. If you want to recalibrate, please do make sure that the air condition is fresh.


The library reads resistance values from the module and calculate the concentration of gas. One thing must be noticed is, the readings of this sensor are not supposed to be used to distinguish the type of gases, but to measure the concentration of a specific gas which is known to be that kind of gas.

The cores of this sensor are more sensitive to CO, NO2 and NH3, the precision of measurement for other gases would be worse.

Note: doCalibrate() function will take 8 seconds before it returns, as said above, at most time you don't need to recalibrate the sensor.


Hardware Installation:

Upload Code:

The content of ReadSensorValue_Grove.ino please refer to below.

    This is a demo to test MutichannelGasSensor library
    This code is running on Xadow-mainboard, and the I2C slave is Xadow-MutichannelGasSensor
    There is a ATmega168PA on Xadow-MutichannelGasSensor, it get sensors output and feed back to master.
    the data is raw ADC value, algorithm should be realized on master.
    please feel free to write email to me if there is any question 
    Jacky Zhang, Embedded Software Engineer

#include <Wire.h>
#include "MutichannelGasSensor.h"

void setup()
    Serial.begin(9600);  // start serial for output
    Serial.println("power on!");

    mutichannelGasSensor.begin(0x04);//the default I2C address of the slave is 0x04
    while(mutichannelGasSensor.readR0() < 0)
        Serial.println("sensors init error!!");
    Serial.print("Res0[0]: ");
    Serial.print("Res0[1]: ");
    Serial.print("Res0[2]: ");

void loop()
    Serial.print("Res[0]: ");
    Serial.print("Res[1]: ");
    Serial.print("Res[2]: ");
    Serial.print("NH3: ");
    Serial.print("CO: ");
    Serial.print("NO2: ");

Arduino environment, and select the correct serial port Arduino is using.
By opening the serial monitor, you can see the raw data read from sensor.


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