How To: use multiple CJMCU-8110

[KapakoProf]

Hi, I am rather new in programming and wonder how to compact the code I wrote for using a flexible number of CJMCU-8110 connected to my NodeMCU. In the attached test code below I have 2 connected, but in the near future I want to expand to 3 or 4 and would like to drive that by a variable (f.i. int SensorNumber = 2) instead of duplicating the code for each sensor.

Who can guide me to a solution?

#include <Arduino.h>
#include <Wire.h>    // I2C library
#include "ccs811.h"  // CCS811 library
#include "ClosedCube_HDC1080.h"

CCS811 ccs811_1;
CCS811 ccs811_2;

ClosedCube_HDC1080 HDC1080_1;
ClosedCube_HDC1080 HDC1080_2;

int SDApin;
int SCLpin = D1;

HDC1080_SerialNumber sernum;
char format[12];
bool vBootphase = true;
uint16_t eco2, etvoc, errstat, raw;

void setup() {Serial.begin(115200); while(!Serial){;}}

void loop() 
{
  if (vBootphase == true)
  {
    // Channel 1: Setup
    SDApin = D2;
    Wire.begin(SDApin, SCLpin);
    delay(500);
    // ** CCS811 **
    Serial.println("");
    Serial.println("*** CCS1 ***");
    Serial.print("CCS :");
    ccs811_1.set_i2cdelay(50);
    ccs811_1.begin();
    delay(500);
    ccs811_1.start(CCS811_MODE_1SEC);
    delay(1000);
    Serial.print("setup: hardware    version: "); Serial.println(ccs811_1.hardware_version(),HEX);
    Serial.print("setup: bootloader  version: "); Serial.println(ccs811_1.bootloader_version(),HEX);
    Serial.print("setup: application version: "); Serial.println(ccs811_1.application_version(),HEX);
    // HDC1080
    HDC1080_1.begin(0x40);
    Serial.print("Manufacturer ID=0x");
    Serial.println(HDC1080_1.readManufacturerId(), HEX); // 0x5449 ID of Texas Instruments
    Serial.print("Device ID=0x");
    Serial.println(HDC1080_1.readDeviceId(), HEX); // 0x1050 ID of the device
    Serial.print("Device Serial Number=");
    sernum = HDC1080_1.readSerialNumber();
    sprintf(format, "%02X-%04X-%04X", sernum.serialFirst, sernum.serialMid, sernum.serialLast);
    Serial.println(format);

    // Channel 2: Setup
    SDApin = D6;
    Wire.begin(SDApin, SCLpin);
    delay(500);
    // ** CCS811 **
    Serial.println("*** CCS2 ***");
    // Print CCS811 versions
    Serial.print("CCS2 :");
    ccs811_2.set_i2cdelay(50);
    ccs811_2.begin();
    delay(500);
    ccs811_2.start(CCS811_MODE_1SEC);
    delay(1000);
    Serial.print("setup: hardware    version: "); Serial.println(ccs811_2.hardware_version(),HEX);
    Serial.print("setup: bootloader  version: "); Serial.println(ccs811_2.bootloader_version(),HEX);
    Serial.print("setup: application version: "); Serial.println(ccs811_2.application_version(),HEX);
    // HDC1080
    HDC1080_2.begin(0x40);
    Serial.print("Manufacturer ID=0x");
    Serial.println(HDC1080_2.readManufacturerId(), HEX); // 0x5449 ID of Texas Instruments
    Serial.print("Device ID=0x");
    Serial.println(HDC1080_2.readDeviceId(), HEX); // 0x1050 ID of the device
    Serial.print("Device Serial Number=");
    sernum = HDC1080_2.readSerialNumber();
    sprintf(format, "%02X-%04X-%04X", sernum.serialFirst, sernum.serialMid, sernum.serialLast);
    Serial.println(format);

    vBootphase = false;
  }
  else
  {
    // Channel 1
    SDApin = D2;
    Wire.begin(SDApin, SCLpin);
    delay(500);
    // ** CCS811 **
    Serial.print("\nSensor connected on: ");
    Serial.print("SDA - ");Serial.print(SDApin); Serial.print(" | SCL - ");Serial.print(SCLpin);
    Serial.print("\n");
    ccs811_1.read(&eco2,&etvoc,&errstat,&raw);
    delay(500);
    Serial.print("ErrStat: ");Serial.print(errstat);Serial.print(" | ");Serial.println(ccs811_1.errstat_str(errstat));
    if(!errstat==CCS811_ERRSTAT_OK) 
    {
      Serial.print("CCS811-1: ");
      Serial.println("Failed to read from sensor");
      ccs811_1.begin();
      delay(500);
      ccs811_1.start(CCS811_MODE_1SEC);
    }
    else
    { 
      Serial.print("CCS811-1: ");
      Serial.print("eco2=");    Serial.print(eco2);     Serial.print(" ppm | ");
      Serial.print("etvoc=");   Serial.print(etvoc);    Serial.print(" ppb");
      Serial.print("\n");
    }
    // ** HDC1080 **
    Serial.print("T="); Serial.print(HDC1080_1.readTemperature()); Serial.print("C");
    Serial.print(", RH="); Serial.print(HDC1080_1.readHumidity()); Serial.println("%");

    // Channel 2
    SDApin = D6;
    Wire.begin(SDApin, SCLpin);
    delay(500);
    // ** CCS811 **
    Serial.print("Sensor connected on: ");
    Serial.print("SDA - ");Serial.print(SDApin); Serial.print(" | SCL - ");Serial.print(SCLpin);
    Serial.print("\n");
    ccs811_2.read(&eco2,&etvoc,&errstat,&raw);
    delay(500);
    Serial.print("ErrStat: ");Serial.print(errstat);Serial.print(" | ");Serial.println(ccs811_2.errstat_str(errstat));
    if(errstat!=CCS811_ERRSTAT_OK) 
    {
      Serial.print("CCS811-2: ");
      Serial.println("Failed to read from sensor");
      ccs811_1.begin();
      delay(500);
      ccs811_2.start(CCS811_MODE_1SEC);
    }
    else
    { 
      Serial.print("CCS811-2: ");
      Serial.print("eco2=");    Serial.print(eco2);     Serial.print(" ppm | ");
      Serial.print("etvoc=");   Serial.print(etvoc);    Serial.print(" ppb");
      Serial.print("\n");
    }
    // ** HDC1080 **
    Serial.print("T="); Serial.print(HDC1080_1.readTemperature()); Serial.print("C");
    Serial.print(", RH="); Serial.print(HDC1080_1.readHumidity()); Serial.println("%");

    delay(10000);
  }
}

20200514_PostedCode.txt

[maarten-pennings]

There are two problems. The first problem, the one you ask, is a software design problem "how to avoid duplication of code". What I would suggest is to create an array of ccs811 objects. That way you can simply loop over them.

The second problem is a hardware problem. I2C devices have an address. On one I2C bus every address can only occur once! The ccs811 helps a bit: there is an io pin you can pull high or low and with that you can select between two addresses. In short one I2C bus has max two ccs811s.

[KapakoProf]

Thanks Maarten. I have changed my code to use an array and now loop the code which is single available. While I do not have enough pins available (other sensors and muxes) yo create multiple I2C busses I now share the SCL pin between 4 css811 and have 2 different pins for SDA which are set in the loop. Works perfect. May be I eventually will end up in using multiple NodeMCU, but for now it is ok. Thanks.