MH-Z14A - датчик углекислого газа, сравнение с конкурентами.

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///                    © tykhon, 2019
///////////////////////////////////////////////////////////////////////

/*
MH-Z19
TX: 3<->5 A0
RX: 3<->5 A1
PWM:      12
Gnd:      Gnd
Vin:      +5v


MH-Z14A
1_+5v:    +5v
2_Gnd:    Gnd
6_Pwm:
11_RX: 3<->5 7
10_TX: 3<->5 6


S8:
G+:       +5v
G0:       Gnd
Rx: 3<->5 A3
Tx: 3<->5 A2


LGAQS-HT01
SCL:      A5
SDA:      A4
Gnd:      Gnd
VDD:      3.3v


BMP280
SCL:      A5
SDA:      A4
Gnd:      Gnd
VDD:      3.3v

DS3231
SCL:      A5
SDA:      A4
Gnd:      Gnd
VDD:      5v


TFT
Led: -> 150 Ohm -> 5v
SCK: -> 1 KOhm -> 13
SDA: -> 1 KOhm -> 11
A0:  -> 1 KOhm -> 8
Reset: -> 1 KOhm ->  9
CS:  -> 1 KOhm -> 10
Gnd:      Gnd
Vcc:      5v

*/

#include <Adafruit_GFX.h>                 // for LCD Core graphics library
#include <Adafruit_ST7735.h>              // for LCD  Hardware-specific library
#include <CCS811.h>                       // for TVOC sensor
#include <Adafruit_Sensor.h>              // for bme280
#include <Adafruit_BME280.h>              // for bme280
#include <SoftwareSerial.h>
#include "Wire.h"

#define TFT_CS     10
#define TFT_RST    9 
#define TFT_DC     8

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS,  TFT_DC, TFT_RST);

#define SEALEVELPRESSURE_HPA (1013.25)      // for bme280
Adafruit_BME280 bme;                        // for bme280 I2C


#define CCS811_ADDR 0x5A                     // for LGAQS-HT01 or ccs811
#define SI7021_ADDR 0x40                     // for LGAQS-HT01 or si7021
#define WAKE_PIN  5                          // for LGAQS-HT01 or ccs811
#define DS1307_ADDR 0x68                     // RTC address

CCS811 sensor;

float si7021_h = 0;
float si7021_t = 0;
unsigned int data[2];
int ccs188_co2 = 0;
int ccs188_tvoc = 0;


int z14_co2;
int z19_co2;
int z19_t;
int z19_ss;


int ccs188_co2_last;
int ccs188_tvoc_last;
int z14_co2_last;
int z19_co2_last;


unsigned long s8_co2_sum = 0;
unsigned long z14_co2_sum = 0;
unsigned long z19_co2_sum = 0;
unsigned long ccs188_co2_sum = 0;
unsigned long ccs188_tvoc_sum = 0;
unsigned long bme_t_sum = 0;
unsigned long bme_h_sum = 0;
unsigned long bme_p_mm_sum = 0;
unsigned int polls = 0;
unsigned long s8_co2 = 0;
unsigned long s8_co2_last = 0;

int bme_t;
int bme_h;
float bme_p;
int bme_p_mm;
const float hpa2mm = 133.3224;

SoftwareSerial mySerial_z19(A0, A1);     
SoftwareSerial mySerial_s8(A2, A3);      
SoftwareSerial mySerial_z14(7, 6);       

byte cmd_z14[9] = {0xFF,0x01,0x86,0x00,0x00,0x00,0x00,0x00,0x79}; 
unsigned char response_z14[9]; 
String ppmString = " ";

byte cmd_z19[9] = {0xFF,0x01,0x86,0x00,0x00,0x00,0x00,0x00,0x79}; 
byte cmd_s8[7] = {0xFE,0x44,0x00,0x08,0x02,0x9F,0x25}; 
unsigned char response_z19[9];
byte response_s8[] = {0,0,0,0,0,0,0};

unsigned int current_minute, lastminute;
int second_delay = 30000;                    // delay between measurements, ms
int work_period = 3;                        // period for recording data, min

////////////////////////////////////////   functions    //////////////////////////////////////////////


byte bcdToDec(byte val)  {
  return ( (val/16*10) + (val%16) );
}


String getdate(){
  Wire.beginTransmission(DS1307_ADDR);      // Reset the register pointer
  byte zero = 0x00;
  Wire.write(zero);
  Wire.endTransmission();
  Wire.requestFrom(DS1307_ADDR, 7);
  int secondint = bcdToDec(Wire.read());
  int minuteint = bcdToDec(Wire.read());
  current_minute = minuteint;
  int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time
  int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday
  int monthDay = bcdToDec(Wire.read());
  int month = bcdToDec(Wire.read());
  int year = bcdToDec(Wire.read());
  String second = String(secondint); if (secondint < 10) {second ="0"+second;};
  String minute = String(minuteint); if (minuteint < 10) {minute ="0"+minute;};
  return String(hour)+":"+minute+":"+second+" "+String(monthDay)+"/"+String(month)+"/"+String(year);
}



void sendRequest_s8(byte packet[]){ 
 mySerial_s8.begin(9600);
 while(!mySerial_s8.available()){                       //keep sending request until we start to get a response 
    mySerial_s8.write(cmd_s8,7); 
    delay(50); 
 } 
 int timeout=0;                                         //set a timeout counter 
  while(mySerial_s8.available() < 7 ) {                 //Wait to get a 7 byte response 
    timeout++; 
    if(timeout > 10) {                                  //if it takes to long there was probably an error 
        while(mySerial_s8.available())                  //flush whatever we have 
        mySerial_s8.read(); 
        break;                                          //exit and try again 
    } 
    delay(50); 
  } 
 for (int i=0; i < 7; i++) { 
      response_s8[i] = mySerial_s8.read(); 
 }
  mySerial_s8.end();
}                      



unsigned long getValue_s8(byte packet[]) 
{ 
 int high = packet[3];                                   //high byte for value is 4th byte in packet in the packet 
 int low = packet[4];                                    //low byte for value is 5th byte in the packet 
 unsigned long val = high*256 + low;                     //Combine high byte and low byte with this formula to get value 
 return val; 
}



void sendRequest_SI7021(){
  Wire.beginTransmission(SI7021_ADDR);
  Wire.endTransmission();
  delay(500);
  Wire.requestFrom(SI7021_ADDR, 2);                         // Request 2 bytes of data
  if(Wire.available() == 2)                                 // Read 2 bytes of data to get humidity
  {
    data[0] = Wire.read();
    data[1] = Wire.read();
  }
  float hum = ((data[0] * 256.0) + data[1]);                // Convert the data
  si7021_h = ((125 * hum) / 65536.0) - 6;
  Wire.begin();
  Wire.beginTransmission(SI7021_ADDR);                      // Send temperature measurement command
  Wire.write(0xF3);
  Wire.endTransmission();
  delay(500);
  Wire.requestFrom(SI7021_ADDR, 2);                         // Request 2 bytes of data
  if(Wire.available() == 2)                                 // Read 2 bytes of data for temperature
  {
    data[0] = Wire.read();
    data[1] = Wire.read();
  }
  float temp  = ((data[0] * 256.0) + data[1]);              // Convert the data
  si7021_t = ((175.72 * temp) / 65536.0) - 46.85;           // 
}


void sendRequest_ccs188(){
  sensor.compensate(si7021_t, si7021_h);                    // replace with t and rh values from sensor
  sensor.getData();
  ccs188_co2 = sensor.readCO2();
  ccs188_tvoc = sensor.readTVOC();
}



void sendRequest_z14(){
  mySerial_z14.begin(9600);
  mySerial_z14.write(cmd_z14, 9);
  memset(response_z14, 0, 9);
  mySerial_z14.readBytes(response_z14, 9);

  int i;
  byte crc = 0;
  for (i = 1; i < 8; i++) crc+=response_z14[i];
  crc = 255 - crc;
  crc++;
  if ( !(response_z14[0] == 0xFF && response_z14[1] == 0x86 && response_z14[8] == crc) ) {
    Serial.println("CRC error z14: " + String(crc) + " / "+ String(response_z14[8]));
  } else { 
    unsigned int responseHigh = (unsigned int) response_z14[2];
    unsigned int responseLow = (unsigned int) response_z14[3];
  z14_co2 = (256*responseHigh) + responseLow;
  };
  mySerial_z14.end();
}


void sendRequest_z19(){
  mySerial_z19.begin(9600);
  mySerial_z19.write(cmd_z19, 9);
  memset(response_z19, 0, 9);
  mySerial_z19.readBytes(response_z19, 9);
  int i;
  byte crc = 0;
  for (i = 1; i < 8; i++) crc+=response_z19[i];
  crc = 255 - crc;
  crc++;
  if (response_z19[0] != 0xFF) {Serial.println("CRC error z19: response_z19[0] != 0xFF: " + String(response_z19[0]));};
  if (response_z19[1] != 0x86) {Serial.println("CRC error z19: response_z19[1] != 0x86: " + String(response_z19[1]));};
  if (response_z19[8] != crc) {Serial.println("CRC error z19: response_z19[8] != crc: " + String(response_z19[8]) + " / "+ String(crc));};
  unsigned int responseHigh = (unsigned int) response_z19[2];
  unsigned int responseLow = (unsigned int) response_z19[3];
  unsigned int responseTT = (unsigned int) response_z19[4];
  unsigned int responseSS = (unsigned int) response_z19[5];
  z19_t = responseTT-40;
  z19_ss =  responseSS;
  z19_co2 = (256*responseHigh) + responseLow;
  mySerial_z19.end();
}

void tft_form(){
  tft.setTextSize(2);
  tft.setCursor(0, 4);
  tft.print("ccs: ");
  tft.setCursor(0, 30);
  tft.print("z19: ");
  tft.setCursor(0, 60);
  tft.print("z14: ");
  tft.setCursor(0, 90);
  tft.print("s8: ");
}


void tft_output(){
  tft.setTextSize(2);
  tft.setTextColor(ST7735_BLACK);

  tft.setCursor(60, 4);
  tft.print(String(ccs188_co2_last));
  tft.print(String("/"));
  tft.print(String(ccs188_tvoc_last));
  tft.setTextColor(ST7735_WHITE);
  tft.setCursor(60, 4);
  tft.print(String(ccs188_co2));
  tft.print(String("/"));
  tft.print(String(ccs188_tvoc));
  ccs188_co2_last = ccs188_co2;
  ccs188_tvoc_last = ccs188_tvoc;

  tft.setCursor(60, 30);
  tft.setTextColor(ST7735_BLACK);
  tft.print(String(z19_co2_last));
  tft.setCursor(60, 30);
  tft.setTextColor(ST7735_WHITE);
  tft.print(String(z19_co2));
  z19_co2_last = z19_co2;

  tft.setCursor(60, 60);
  tft.setTextColor(ST7735_BLACK);
  tft.print(String(z14_co2_last));
  tft.setCursor(60, 60);
  tft.setTextColor(ST7735_WHITE);
  tft.print(String(z14_co2));
  z14_co2_last = z14_co2;

  tft.setCursor(60, 90);
  tft.setTextColor(ST7735_BLACK);
  tft.print(String(s8_co2_last));
  tft.setCursor(60, 90);
  tft.setTextColor(ST7735_WHITE);
  tft.print(String(s8_co2));
  s8_co2_last = s8_co2;
  
  tft.setTextSize(1);
  tft.fillRect(0, 117, 160, 120, ST7735_BLACK);
  tft.setCursor(0, 117);
  tft.print(String(getdate()));

}

///////////////////////////////////////  setup   /////////////////////////////////////////

void setup(void) {
  Serial.begin(9600);

    bool status;
    status = bme.begin();
    if (!status) {
        Serial.println("Could not find a valid BME280 sensor, check wiring!");
        while (1);
    }
    delay(100); // let sensor boot up


  tft.initR(INITR_BLACKTAB);   // initialize a ST7735S chip, black tab

  Serial.println("init");
  if(!sensor.begin(uint8_t(CCS811_ADDR), uint8_t(WAKE_PIN)))
    Serial.println("Init fail");

  tft.setTextWrap(false); // Allow text to run off right edge
  tft.setRotation(3);
  tft.fillScreen(ST7735_BLACK);
  tft_form();
}

////////////////////////////////////////////////   loop    /////////////////////////////////////////////////////

void loop() {
  sendRequest_SI7021();
  sendRequest_ccs188();
  sendRequest_z14();
  sendRequest_z19();
  sendRequest_s8(cmd_s8); 
  s8_co2 = getValue_s8(response_s8); 
  bme_p = bme.readPressure();
  bme_p_mm = int(bme_p/hpa2mm);
  bme_h = bme.readHumidity();
  bme_t = bme.readTemperature();

  s8_co2_sum += s8_co2;
  z14_co2_sum += z14_co2;
  z19_co2_sum += z19_co2;
  ccs188_co2_sum += ccs188_co2;
  ccs188_tvoc_sum += ccs188_tvoc;
  bme_t_sum += bme_t;
  bme_h_sum += bme_h;
  bme_p_mm_sum += bme_p_mm;
  polls ++;
  getdate();
  tft_output();
  if (((current_minute)%work_period == 0)&&(lastminute != current_minute)) {
    s8_co2 = s8_co2_sum/polls;
    z14_co2 = z14_co2_sum/polls;
    z19_co2 = z19_co2_sum/polls;
    ccs188_co2 = ccs188_co2_sum/polls;
    ccs188_tvoc = ccs188_tvoc_sum/polls;
    bme_t = bme_t_sum/polls;
    bme_h = bme_h_sum/polls;  
    bme_p_mm = bme_p_mm_sum/polls;
    
    String dataString = getdate()+"  s8:  "+String(s8_co2)+"  z14:  "+String(z14_co2)+"  z19:  "+String(z19_co2)+"  z19_t:  "+String(z19_t)+"  ccs:  "+String(ccs188_co2)+  "  TVOC:  "+String(ccs188_tvoc)+"  ccs_t:  "+String(si7021_t)+"  ccs_h:  "+String(si7021_h)+"  bme_t:  "+String(bme_t)+"  bme_h:  "+String(bme_h);
    dataString.replace(".",",");
    dataString.replace("  ","\t");
    Serial.println(dataString);
    lastminute = current_minute;
    polls = 0;
    s8_co2_sum = 0;
    z14_co2_sum = 0;
    z19_co2_sum = 0;
    ccs188_co2_sum = 0;
    ccs188_tvoc_sum = 0;
    bme_t_sum = 0;
    bme_h_sum = 0;
    bme_p_mm_sum = 0;
  };

  delay(second_delay);
}