[Tutorial] Extracting data from multichannel sensor with ESP8266

1. Devices

• ESP8266 

• Multi-channel sensor

• some jumper wires or four pins cable

2. Install the library for multi-channel sensors

The so-called library is actually a project which has been created by other people. it may include some outside h.files and cpp.files or just a .ino file that can be directly used. How to manage the outside library?
Firstly, download the library (take air quality sensor library as an example) from the link: https://github.com/Seeed-Studio/Mutichannel_Gas_Sensor/archive/master.zip. Secondly, move this library into your Arduino IDE libraries. Thirdly, select sketch->includeLibrary->add a zip. library->choose the downloaded library.

3. Chose the right board for ESP8266

 4. Source code (disconnect the sensor during uploading codes) 

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

void setup()
{
    Serial.begin(115200);  // start serial for output
    Serial.println("power on!");
    gas.begin(0x04);//the default I2C address of the slave is 0x04
    gas.powerOn();
    Serial.print("Firmware Version = ");
    Serial.println(gas.getVersion());
}

void loop()
{
    float c;

    c = gas.measure_NH3();
    Serial.print("The concentration of NH3 is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_CO();
    Serial.print("The concentration of CO is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_NO2();
    Serial.print("The concentration of NO2 is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_C3H8();
    Serial.print("The concentration of C3H8 is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_C4H10();
    Serial.print("The concentration of C4H10 is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_CH4();
    Serial.print("The concentration of CH4 is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_H2();
    Serial.print("The concentration of H2 is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    c = gas.measure_C2H5OH();
    Serial.print("The concentration of C2H5OH is ");
    if(c>=0) Serial.print(c);
    else Serial.print("invalid");
    Serial.println(" ppm");

    delay(1000);
}

 4. output