Air Quality Analyzer

Analyses home air quality and records the values in a SD card.

Mar 8, 2018

•

5595 views

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3 respects

air quality

environmental sensing

Components and supplies

ADAFRUIT FEATHER M0 ADALOGGER

Jumper wires (generic)

MONOCHROME 0.96" 128X64 OLED GRAPHIC DISPLAY

ADAFRUIT CCS811 AIR QUALITY SENSOR BREAKOUT - VOC AND ECO2

DHT11 Temperature & Humidity Sensor (4 pins)

Tools and machines

Soldering iron (generic)

Apps and platforms

Arduino IDE

Project description

Code

Software version 2.0.3

arduino

This is the version 2.0.3 of the software. Has better time handling and improved display of data. Date and time now displayed on the main screen. Please inform if you have problems.

1/* Air Quality Sensor V2.0.3 2018/03/27 Luis Sousa */
2
3#include  <SPI.h> //Standard lib
4#include <SD.h> //author=Arduino, SparkFun version=1.2.2
5#include  <DHT.h>//author=Adafruit version=1.3.0
6//#include <Wire.h>
7#include <RTCZero.h>  //author=Arduino version=1.5.2
8#include <RTClib.h> //author=Adafruit version=1.2.1  
9#include <Adafruit_GFX.h> //author=Adafruit version=1.2.3
10#include <Adafruit_SSD1306.h>  //author=Adafruit version=1.1.2
11#include <Adafruit_CCS811.h>//author=Adafruit  version=1.0.0
12
13//Levels
14//temp levels
15#define low_temp_level_1 18
16#define  low_temp_level_2 12
17#define low_temp_level_3 8
18#define high_temp_level_1 29
19#define  high_temp_level_2 35
20#define high_temp_level_3 40
21//rh levels
22#define low_rh_level_1  40
23#define low_rh_level_2 30
24#define low_rh_level_3 20
25#define high_rh_level_1  70
26#define high_rh_level_2 80
27#define high_rh_level_3 90
28//co2 levels
29#define  co2_level_1 1000
30#define co2_level_2 1500
31#define co2_level_3 3000
32//TVOC  levels
33#define tvoc_level_1 100
34#define tvoc_level_2 500
35#define tvoc_level_3  1000
36
37//Status LEDS
38#define green_led  14
39#define yellow_led 15
40#define  red_led 16
41
42//OLED Display If using software SPI (the default case):
43#define  OLED_MOSI   6
44#define OLED_CLK   10
45#define OLED_DC    11
46#define OLED_CS    12
47#define OLED_RESET 5
48#define display_refresh_interval 1 //2 seconds  refresh
49Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
50
51//DHT  Sensor
52#define DHTPIN 19     // what pin DHT is connected to (19=A5 on this Board)
53#define  DHTTYPE DHT11   // DHT 11
54#define DHT_read_interval 3 //Read temp every X seconds
55DHT  dht(DHTPIN, DHTTYPE); //object dht creation
56
57//SD Card
58#define cardSelect  4  //SD chip select pin
59#define ficheiro "dados.csv" // nome do ficheiro de  dados
60//#define Serial_Header "Date,Hour,Vbat,Temp,%RH,eCO2,TVOC,STATUS"
61#define  SD_Header "Date,Hour,Vbat,min_Temp,Max_Temp,min_RH,Max_RH,min_eCO2,Max_eCO2,min_TVOC,Max_TVOC,STATUS"
62#define  SD_write_interval 300 //seconds between SD writes
63#define SD_led 8 //Green LED
64
65//RTC
66RTCZero  rtc;  // Create an rtc object /
67
68//Vbat read
69#define vbatpin A7    //pin  to read Bat Voltage
70#define vbat_read_interval 30 //seconds between vbat readings
71float  measuredvbat;
72
73//Set up variables using the SD utility library functions:
74Sd2Card  card;
75SdVolume volume;
76SdFile root;
77
78//Set up CCS811 object ccs
79Adafruit_CCS811  ccs;
80#define CCS811_read_interval 3 //Read data every X seconds
81
82//variable  declaration
83unsigned long nseconds; //seconds since start of day.
84unsigned  long SD_last_write = 0;
85unsigned long vbat_last_read = 0;
86unsigned long DHT_last_read  = 0;
87unsigned long CCS811_last_read = 0;
88unsigned long display_last_refresh  = 0;
89boolean error = false; //clear errors
90boolean alarm = false; //clear  alarms
91boolean alarm_level_0 = false;
92boolean alarm_level_1 = false;
93boolean  alarm_level_2 = false;
94boolean alarm_level_3 = false;
95float eco2 = 0.0;
96float  max_eco2 = 0.0;
97float min_eco2 = 10000;
98float tvoc = 0.0;
99float max_tvoc  = 0.0;
100float min_tvoc = 10000;
101float temp = 0.0;
102float max_temp = 0.0;
103float  min_temp = 100;
104float rh = 0.0;
105float max_rh = 0.0;
106float min_rh = 100;
107String  errorString = "";
108String alarmString = "";
109//byte day = 27;
110//byte  month = 03;
111//byte year = 18;
112//byte seconds = 00;
113//byte minutes = 00;
114//byte  hours = 12;
115
116void setup() {
117  pinMode(SD_led, OUTPUT);// initialize digital  pin 8 as an output.
118  pinMode(green_led, OUTPUT);// initialize digital pin as  an output.
119  pinMode(yellow_led, OUTPUT);// initialize digital pin as an output.
120  pinMode(red_led, OUTPUT);// initialize digital pin as an output.
121
122  //Serial  Port Initialization
123  Serial.begin(57600);
124  delay (300);//wait for the serial  to be ready
125  /*
126    while (!Serial) {
127    ; // wait for serial port to  connect. Needed for native USB port only
128    }
129  */
130
131  //RTC initialization
132  DateTime now;
133  now = (DateTime(F(__DATE__), F(__TIME__))); //Compilation time
134  now=now+20; //compensation for Compile + Reset time
135  rtc.begin(); // initialize  RTCZero
136  rtc.setTime(now.hour(), now.minute(), now.second());
137  rtc.setDate(now.day(),  now.month(), now.year()-2000);
138
139  //DHT Initialisation
140  dht.begin();
141
142  // CCS811 test
143  if (!ccs.begin()) {
144    Serial.println("Failed to start  CCS811 sensor! Please check your wiring.");
145    errorString = "CCS811 Error";
146    //while (1);
147  }
148  //calibrate CCS811 temperature sensor
149  while (!ccs.available());
150  temp = ccs.calculateTemperature();
151  ccs.setTempOffset(temp - 25.0);
152
153  //Display initialization
154  display.begin(SSD1306_SWITCHCAPVCC);// by default,  we'll generate the high voltage from the 3.3v line internally!
155  display.clearDisplay();  // Clear the buffer.
156
157  //SD Initialization and Test
158  Serial.print("\
159Initializing  SD card...");
160  // we'll use the initialization code from the utility libraries
161  // since we're just testing if the card is working!
162  if (!card.init(SPI_HALF_SPEED,  cardSelect)) {
163    Serial.println("initialization failed. Things to check: ");
164    Serial.println("* is a card inserted ? ");
165    Serial.println("* is your  wiring correct ? ");
166    Serial.println("* did you change the chipSelect pin  to match your shield or module ? ");
167    //while (1);
168    errorString = "SD  Card Error";
169  } else {
170    Serial.println("Wiring is correct and a card  is present.");
171  }
172  // print the type of card
173  Serial.println();
174  Serial.print("Card type :         ");
175  switch (card.type()) {
176    case  SD_CARD_TYPE_SD1:
177      Serial.println("SD1");
178      break;
179    case  SD_CARD_TYPE_SD2:
180      Serial.println("SD2");
181      break;
182    case  SD_CARD_TYPE_SDHC:
183      Serial.println("SDHC");
184      break;
185    default:
186      Serial.println("Unknown");
187  }
188  // Now we will try to open the 'volume'/'partition'  - it should be FAT16 or FAT32
189  if (!volume.init(card)) {
190    Serial.println("Could  not find FAT16 / FAT32 partition.\
191Make sure you've formatted the card");
192    //while (1);
193    errorString = "SD Format Error";
194  }
195  Serial.print("Clusters:          ");
196  Serial.println(volume.clusterCount());
197  Serial.print("Blocks  x Cluster:  ");
198  Serial.println(volume.blocksPerCluster());
199  Serial.print("Total  Blocks:      ");
200  Serial.println(volume.blocksPerCluster() * volume.clusterCount());
201  Serial.println();
202  // print the type and size of the first FAT-type volume
203  uint32_t volumesize;
204  Serial.print("Volume type is:    FAT");
205  Serial.println(volume.fatType(),  DEC);
206  volumesize = volume.blocksPerCluster();    // clusters are collections  of blocks
207  volumesize *= volume.clusterCount();       // we'll have a lot of  clusters
208  volumesize /= 2;                           // SD card blocks are always  512 bytes (2 blocks are 1KB)
209  Serial.print("Volume size (Kb):  ");
210  Serial.println(volumesize);
211  Serial.print("Volume size (Mb):  ");
212  volumesize /= 1024;
213  Serial.println(volumesize);
214  Serial.print("Volume size (Gb):  ");
215  Serial.println((float)volumesize /  1024.0);
216  Serial.println("\
217Files found on the card (name, date and size in  bytes): ");
218  root.openRoot(volume);
219  // list all files in the card with  date and size
220  root.ls(LS_R | LS_DATE | LS_SIZE);
221  if (!SD.begin(cardSelect))  {
222    errorString = ("No SD Card");
223  }
224  else {
225    File logfile  = SD.open(ficheiro, FILE_WRITE);
226    if (!logfile)
227      errorString = ("File  Error");
228    else {
229      Serial.print("Gravando em: ");
230      Serial.println(ficheiro);
231      logfile.println(SD_Header);
232      logfile.close();
233    }
234  }
235}
236
237void  loop() {
238  //How many seconds since 0H (start of day)
239  nseconds = 3600 *  rtc.getHours() + 60 * rtc.getMinutes() + rtc.getSeconds();
240
241  //measure Vbat
242  if (abs(nseconds - vbat_last_read >= vbat_read_interval)) //time to read vbat
243  {
244    measuredvbat = analogRead(vbatpin);
245    measuredvbat *= 2; // we divided  by 2, so multiply back
246    measuredvbat *= 3.3; // Multiply by 3.3V, our reference  voltage
247    measuredvbat /= 1024; // convert to voltage
248    vbat_last_read  = nseconds;
249  }
250  // Reading temperature and humidity
251  //if (nseconds  % DHT_read_interval == 0) //Time to read temp
252  if (abs(nseconds - DHT_last_read  >= DHT_read_interval)) //time to read DHT
253  {
254    rh = dht.readHumidity();
255    temp = dht.readTemperature();  // Read temperature as Celsius (the default)
256    float f = dht.readTemperature(true);   // Read temperature as Fahrenheit (isFahrenheit  = true)
257
258    if (isnan(rh) || isnan(temp) || isnan(f)) {
259      Serial.println("Failed  to read from DHT sensor!");// Check if any reads failed and exit early (to try  again).
260      error = true;
261      errorString = ("DHT Error");
262      //return;
263    }
264    DHT_last_read = nseconds;
265  }
266  // Reading eCO2 & TVOC
267  //if  (nseconds % CCS811_read_interval == 0) //Time to read data
268  if (abs(nseconds  - CCS811_last_read >= CCS811_read_interval)) //time to read CCS811
269  {
270    if  (ccs.available()) {
271      //temp = ccs.calculateTemperature();
272      if (!ccs.readData())  {
273        eco2 = ccs.geteCO2();
274        tvoc = ccs.getTVOC();
275      }
276      else {
277        error = true;
278        Serial.println("CCS811 sensor  error!");
279        errorString = "CCS811 error";
280        //while(1);
281      }
282      CCS811_last_read = nseconds;
283    }
284  }
285
286  //Alarm levels
287  alarm_level_3 = temp > high_temp_level_3 || temp < low_temp_level_3 || rh > high_rh_level_3  || rh < low_rh_level_3 || eco2 > co2_level_3 || tvoc > tvoc_level_3;
288  alarm_level_2  = temp > high_temp_level_2 || temp < low_temp_level_2 || rh > high_rh_level_2 ||  rh < low_rh_level_2 || eco2 > co2_level_2 || tvoc > tvoc_level_2;
289  alarm_level_1  = temp > high_temp_level_1 || temp < low_temp_level_1 || rh > high_rh_level_1 ||  rh < low_rh_level_1 || eco2 > co2_level_1 || tvoc > tvoc_level_1;
290  alarm_level_0  = !alarm_level_3 & !alarm_level_2 & !alarm_level_2;
291
292  //Alarm LEDS &  Alarm  Strings
293  if (alarm_level_3) {
294    alarm = true;
295    digitalWrite(green_led,  LOW);
296    digitalWrite(yellow_led, LOW);
297    digitalWrite(red_led, HIGH);
298    if (eco2 > co2_level_3) alarmString = "CO2 High ++";
299    else if (tvoc  > tvoc_level_3) alarmString = "TVOC High ++";
300    else if (rh > high_rh_level_3)  alarmString = "RH High ++";
301    else if (rh < low_rh_level_3) alarmString =  "RH Low --";
302    else if (temp > high_temp_level_3) alarmString = "Temp High  ++";
303    else if (temp < low_temp_level_3) alarmString = "Temp Low --";
304  }
305  else if (alarm_level_2) {
306    alarm = true;
307    digitalWrite(green_led,  LOW);
308    digitalWrite(yellow_led, HIGH);
309    digitalWrite(red_led, LOW);
310    if (eco2 > co2_level_2) alarmString = "CO2 High +";
311    else if (tvoc >  tvoc_level_2) alarmString = "TVOC High +";
312    else if (rh > high_rh_level_2)  alarmString = "RH High +";
313    else if (rh < low_rh_level_2) alarmString =  "RH Low -";
314    else if (temp > high_temp_level_2) alarmString = "Temp High  +";
315    else if (temp < low_temp_level_2) alarmString = "Temp Low -";
316  }
317  else if (alarm_level_1) {
318    alarm = true;
319    digitalWrite(green_led,  LOW);
320    digitalWrite(yellow_led, HIGH);
321    digitalWrite(red_led, LOW);
322    if (eco2 > co2_level_1)alarmString = ("CO2 High");
323    else if (tvoc >  tvoc_level_1) alarmString = "TVOC High";
324    else if (rh > high_rh_level_1)  alarmString = "RH High";
325    else if (rh < low_rh_level_1) alarmString = "RH  Low";
326    else if (temp > high_temp_level_1) alarmString = "Temp High";
327    else if (temp < low_temp_level_1) alarmString = "Temp Low";
328  }
329  else  if (alarm_level_0) {
330    alarm = false;
331    digitalWrite(green_led, HIGH);
332    digitalWrite(yellow_led, LOW);
333    digitalWrite(red_led, LOW);
334    alarmString  = "OK";
335  }
336  //Max and min determination
337  if (temp > max_temp) max_temp  = temp;
338  if (temp < min_temp) min_temp = temp;
339  if (rh > max_rh) max_rh  = rh;
340  if (rh < min_rh) min_rh = rh;
341  if (eco2 > max_eco2) max_eco2 = eco2;
342  if (eco2 < min_eco2) min_eco2 = eco2;
343  if (tvoc > max_tvoc) max_tvoc = tvoc;
344  if (tvoc < min_tvoc) min_tvoc = tvoc;
345
346  //Relatorio serial
347  Serial.print("Data:"  );
348  serial2digits(rtc.getDay());
349  Serial.print("/");
350  serial2digits(rtc.getMonth());
351  Serial.print("/");
352  Serial.print(2000 + rtc.getYear(), DEC);
353  Serial.print("  Hora:" );
354  serial2digits(rtc.getHours());
355  Serial.print(":");
356  serial2digits(rtc.getMinutes());
357  Serial.print(":");
358  serial2digits(rtc.getSeconds());
359  Serial.print("  ");
360  Serial.print("VBat:" ); Serial.print(measuredvbat);
361  Serial.print("  Temp:");   Serial.print(temp);
362  Serial.print(" Humid:");   Serial.print(rh);
363  Serial.print(" CO2:");   Serial.print(eco2);
364  Serial.print(" ppm, TVOC:");  Serial.print(tvoc); Serial.print(" ppb:");
365  Serial.print(" Status:");
366  if (error)
367    Serial.println(errorString);
368  else if (alarm)
369    Serial.println(alarmString);
370  else Serial.println("OK");
371
372  //Data display
373  if (abs(nseconds - display_last_refresh  >= display_refresh_interval)) //time to display information
374  {
375    display.clearDisplay();//  Clean Display
376    display.setTextSize(1);
377    display.setTextColor(WHITE);
378    display.setCursor(0, 0);
379    display.println("Air Quality Analyzer");
380    display.setCursor(0, 8);
381    display2digits(rtc.getDay());
382    display.print("/");
383    display2digits(rtc.getMonth());
384    display.print("/");
385    display.print(2000  + rtc.getYear(), DEC);
386    display.print(" ");
387    display2digits(rtc.getHours());
388    display.print(":");
389    display2digits(rtc.getMinutes());
390    /*display.print(":");
391      display.print(rtc.getSeconds(), DEC);*/
392    display.setCursor(0, 16);
393    display.print("Vbat:");
394    display.setCursor(50, 16);
395    display.print(measuredvbat);  display.print(" V");
396    display.setCursor(0, 24);
397    display.print("Temp:");
398    display.setCursor(50, 24);
399    display.print(temp); display.print(" C");
400    display.setCursor(0, 32);
401    display.print("RH:");
402    display.setCursor(50,  32);
403    display.print(rh); display.print(" %");
404    display.setCursor(0,  40);
405    display.print("eCO2:");
406    display.setCursor(50, 40);
407    display.print(eco2);  display.print(" ppm");
408    display.setCursor(0, 48);
409    display.print("TVOC:");
410    display.setCursor(50, 48);
411    display.print(tvoc); display.print(" ppb");
412    display.setCursor(0, 56);
413    display.print("Status:");
414    display.setCursor(50,  56);
415    if (error) {
416      display.print(errorString);
417    } else if (alarm)  {
418      display.print(alarmString);
419    }
420    else
421    {
422      display.print("OK");
423    }
424    display.display();
425    display_last_refresh = nseconds;
426  }
427  //SD datalog
428  //if (nseconds % SD_write_interval == 0) //Time to log data
429  if (abs(nseconds - SD_last_write >= SD_write_interval)) //Time to log data
430  {
431    File logfile = SD.open(ficheiro, FILE_WRITE);
432    if (logfile) {
433      digitalWrite(SD_led, HIGH); //SD Write begins
434      logfile2digits(rtc.getDay(),  logfile);
435      logfile.print("/");
436      logfile2digits(rtc.getMonth(),  logfile);
437      logfile.print("/");
438      logfile.print(2000 + rtc.getYear(),  DEC);
439      logfile.print(",");
440      logfile2digits(rtc.getHours(), logfile);
441      logfile.print(":");
442      logfile2digits(rtc.getMinutes(), logfile);
443      logfile.print(":");
444      logfile2digits(rtc.getSeconds(), logfile);
445      logfile.print(",");
446      logfile.print(measuredvbat, 2);
447      logfile.print(",");
448      logfile.print(min_temp, 2);
449      logfile.print(",");
450      logfile.print(max_temp,  2);
451      logfile.print(",");
452      logfile.print(min_rh, 2);
453      logfile.print(",");
454      logfile.print(max_rh, 2);
455      logfile.print(",");
456      logfile.print(min_eco2,  2);
457      logfile.print(",");
458      logfile.print(max_eco2, 2);
459      logfile.print(",");
460      logfile.print(min_tvoc, 2);
461      logfile.print(",");
462      logfile.print(max_tvoc,  2);
463      logfile.print(",");
464      if (error)
465        logfile.println(errorString);
466      else if (alarm)
467        logfile.println(alarmString);
468      else logfile.println("OK");
469      logfile.close();
470      SD_last_write = nseconds;
471      digitalWrite(SD_led,  LOW); //SD Write ends
472    }
473    else
474    {
475      error = true;
476      errorString  = ("logfile error");
477    }
478    //Max and min RESET
479    max_eco2 = 0.0;
480    min_eco2 = 10000;
481    max_tvoc = 0.0;
482    min_tvoc = 10000;
483    max_temp  = 0.0;
484    min_temp = 100;
485    max_rh = 0.0;
486    min_rh = 100;
487  }
488  delay(200); //don't use values higher than 1000 or nseconds won't be properly  updated
489}
490
491void display2digits(int number)// create a leading zero for  month/day/hour/minute when <10
492{
493  if (number >= 0 && number < 10) {
494    display.write('0');
495  }
496  display.print(number);
497}
498
499void logfile2digits(int number, File  logfile) // create a leading zero for month/day/hour/minute when <10
500{
501  if  (number >= 0 && number < 10) {
502    logfile.write('0');
503  }
504  logfile.print(number);
505}
506
507void  serial2digits(int number)// create a leading zero for month/day/hour/minute when  <10
508{
509  if (number >= 0 && number < 10) {
510    Serial.write('0');
511  }
512  Serial.print(number);
513}
514

/* Air Quality Sensor V2.0.3 2018/03/27 Luis Sousa */

#include  <SPI.h> //Standard lib
#include <SD.h> //author=Arduino, SparkFun version=1.2.2
#include  <DHT.h>//author=Adafruit version=1.3.0
//#include <Wire.h>
#include <RTCZero.h>  //author=Arduino version=1.5.2
#include <RTClib.h> //author=Adafruit version=1.2.1  
#include <Adafruit_GFX.h> //author=Adafruit version=1.2.3
#include <Adafruit_SSD1306.h>  //author=Adafruit version=1.1.2
#include <Adafruit_CCS811.h>//author=Adafruit  version=1.0.0

//Levels
//temp levels
#define low_temp_level_1 18
#define  low_temp_level_2 12
#define low_temp_level_3 8
#define high_temp_level_1 29
#define  high_temp_level_2 35
#define high_temp_level_3 40
//rh levels
#define low_rh_level_1  40
#define low_rh_level_2 30
#define low_rh_level_3 20
#define high_rh_level_1  70
#define high_rh_level_2 80
#define high_rh_level_3 90
//co2 levels
#define  co2_level_1 1000
#define co2_level_2 1500
#define co2_level_3 3000
//TVOC  levels
#define tvoc_level_1 100
#define tvoc_level_2 500
#define tvoc_level_3  1000

//Status LEDS
#define green_led  14
#define yellow_led 15
#define  red_led 16

//OLED Display If using software SPI (the default case):
#define  OLED_MOSI   6
#define OLED_CLK   10
#define OLED_DC    11
#define OLED_CS    12
#define OLED_RESET 5
#define display_refresh_interval 1 //2 seconds  refresh
Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);

//DHT  Sensor
#define DHTPIN 19     // what pin DHT is connected to (19=A5 on this Board)
#define  DHTTYPE DHT11   // DHT 11
#define DHT_read_interval 3 //Read temp every X seconds
DHT  dht(DHTPIN, DHTTYPE); //object dht creation

//SD Card
#define cardSelect  4  //SD chip select pin
#define ficheiro "dados.csv" // nome do ficheiro de  dados
//#define Serial_Header "Date,Hour,Vbat,Temp,%RH,eCO2,TVOC,STATUS"
#define  SD_Header "Date,Hour,Vbat,min_Temp,Max_Temp,min_RH,Max_RH,min_eCO2,Max_eCO2,min_TVOC,Max_TVOC,STATUS"
#define  SD_write_interval 300 //seconds between SD writes
#define SD_led 8 //Green LED

//RTC
RTCZero  rtc;  // Create an rtc object /

//Vbat read
#define vbatpin A7    //pin  to read Bat Voltage
#define vbat_read_interval 30 //seconds between vbat readings
float  measuredvbat;

//Set up variables using the SD utility library functions:
Sd2Card  card;
SdVolume volume;
SdFile root;

//Set up CCS811 object ccs
Adafruit_CCS811  ccs;
#define CCS811_read_interval 3 //Read data every X seconds

//variable  declaration
unsigned long nseconds; //seconds since start of day.
unsigned  long SD_last_write = 0;
unsigned long vbat_last_read = 0;
unsigned long DHT_last_read  = 0;
unsigned long CCS811_last_read = 0;
unsigned long display_last_refresh  = 0;
boolean error = false; //clear errors
boolean alarm = false; //clear  alarms
boolean alarm_level_0 = false;
boolean alarm_level_1 = false;
boolean  alarm_level_2 = false;
boolean alarm_level_3 = false;
float eco2 = 0.0;
float  max_eco2 = 0.0;
float min_eco2 = 10000;
float tvoc = 0.0;
float max_tvoc  = 0.0;
float min_tvoc = 10000;
float temp = 0.0;
float max_temp = 0.0;
float  min_temp = 100;
float rh = 0.0;
float max_rh = 0.0;
float min_rh = 100;
String  errorString = "";
String alarmString = "";
//byte day = 27;
//byte  month = 03;
//byte year = 18;
//byte seconds = 00;
//byte minutes = 00;
//byte  hours = 12;

void setup() {
  pinMode(SD_led, OUTPUT);// initialize digital  pin 8 as an output.
  pinMode(green_led, OUTPUT);// initialize digital pin as  an output.
  pinMode(yellow_led, OUTPUT);// initialize digital pin as an output.
  pinMode(red_led, OUTPUT);// initialize digital pin as an output.

  //Serial  Port Initialization
  Serial.begin(57600);
  delay (300);//wait for the serial  to be ready
  /*
    while (!Serial) {
    ; // wait for serial port to  connect. Needed for native USB port only
    }
  */

  //RTC initialization
  DateTime now;
  now = (DateTime(F(__DATE__), F(__TIME__))); //Compilation time
  now=now+20; //compensation for Compile + Reset time
  rtc.begin(); // initialize  RTCZero
  rtc.setTime(now.hour(), now.minute(), now.second());
  rtc.setDate(now.day(),  now.month(), now.year()-2000);

  //DHT Initialisation
  dht.begin();

  // CCS811 test
  if (!ccs.begin()) {
    Serial.println("Failed to start  CCS811 sensor! Please check your wiring.");
    errorString = "CCS811 Error";
    //while (1);
  }
  //calibrate CCS811 temperature sensor
  while (!ccs.available());
  temp = ccs.calculateTemperature();
  ccs.setTempOffset(temp - 25.0);

  //Display initialization
  display.begin(SSD1306_SWITCHCAPVCC);// by default,  we'll generate the high voltage from the 3.3v line internally!
  display.clearDisplay();  // Clear the buffer.

  //SD Initialization and Test
  Serial.print("\
Initializing  SD card...");
  // we'll use the initialization code from the utility libraries
  // since we're just testing if the card is working!
  if (!card.init(SPI_HALF_SPEED,  cardSelect)) {
    Serial.println("initialization failed. Things to check: ");
    Serial.println("* is a card inserted ? ");
    Serial.println("* is your  wiring correct ? ");
    Serial.println("* did you change the chipSelect pin  to match your shield or module ? ");
    //while (1);
    errorString = "SD  Card Error";
  } else {
    Serial.println("Wiring is correct and a card  is present.");
  }
  // print the type of card
  Serial.println();
  Serial.print("Card type :         ");
  switch (card.type()) {
    case  SD_CARD_TYPE_SD1:
      Serial.println("SD1");
      break;
    case  SD_CARD_TYPE_SD2:
      Serial.println("SD2");
      break;
    case  SD_CARD_TYPE_SDHC:
      Serial.println("SDHC");
      break;
    default:
      Serial.println("Unknown");
  }
  // Now we will try to open the 'volume'/'partition'  - it should be FAT16 or FAT32
  if (!volume.init(card)) {
    Serial.println("Could  not find FAT16 / FAT32 partition.\
Make sure you've formatted the card");
    //while (1);
    errorString = "SD Format Error";
  }
  Serial.print("Clusters:          ");
  Serial.println(volume.clusterCount());
  Serial.print("Blocks  x Cluster:  ");
  Serial.println(volume.blocksPerCluster());
  Serial.print("Total  Blocks:      ");
  Serial.println(volume.blocksPerCluster() * volume.clusterCount());
  Serial.println();
  // print the type and size of the first FAT-type volume
  uint32_t volumesize;
  Serial.print("Volume type is:    FAT");
  Serial.println(volume.fatType(),  DEC);
  volumesize = volume.blocksPerCluster();    // clusters are collections  of blocks
  volumesize *= volume.clusterCount();       // we'll have a lot of  clusters
  volumesize /= 2;                           // SD card blocks are always  512 bytes (2 blocks are 1KB)
  Serial.print("Volume size (Kb):  ");
  Serial.println(volumesize);
  Serial.print("Volume size (Mb):  ");
  volumesize /= 1024;
  Serial.println(volumesize);
  Serial.print("Volume size (Gb):  ");
  Serial.println((float)volumesize /  1024.0);
  Serial.println("\
Files found on the card (name, date and size in  bytes): ");
  root.openRoot(volume);
  // list all files in the card with  date and size
  root.ls(LS_R | LS_DATE | LS_SIZE);
  if (!SD.begin(cardSelect))  {
    errorString = ("No SD Card");
  }
  else {
    File logfile  = SD.open(ficheiro, FILE_WRITE);
    if (!logfile)
      errorString = ("File  Error");
    else {
      Serial.print("Gravando em: ");
      Serial.println(ficheiro);
      logfile.println(SD_Header);
      logfile.close();
    }
  }
}

void  loop() {
  //How many seconds since 0H (start of day)
  nseconds = 3600 *  rtc.getHours() + 60 * rtc.getMinutes() + rtc.getSeconds();

  //measure Vbat
  if (abs(nseconds - vbat_last_read >= vbat_read_interval)) //time to read vbat
  {
    measuredvbat = analogRead(vbatpin);
    measuredvbat *= 2; // we divided  by 2, so multiply back
    measuredvbat *= 3.3; // Multiply by 3.3V, our reference  voltage
    measuredvbat /= 1024; // convert to voltage
    vbat_last_read  = nseconds;
  }
  // Reading temperature and humidity
  //if (nseconds  % DHT_read_interval == 0) //Time to read temp
  if (abs(nseconds - DHT_last_read  >= DHT_read_interval)) //time to read DHT
  {
    rh = dht.readHumidity();
    temp = dht.readTemperature();  // Read temperature as Celsius (the default)
    float f = dht.readTemperature(true);   // Read temperature as Fahrenheit (isFahrenheit  = true)

    if (isnan(rh) || isnan(temp) || isnan(f)) {
      Serial.println("Failed  to read from DHT sensor!");// Check if any reads failed and exit early (to try  again).
      error = true;
      errorString = ("DHT Error");
      //return;
    }
    DHT_last_read = nseconds;
  }
  // Reading eCO2 & TVOC
  //if  (nseconds % CCS811_read_interval == 0) //Time to read data
  if (abs(nseconds  - CCS811_last_read >= CCS811_read_interval)) //time to read CCS811
  {
    if  (ccs.available()) {
      //temp = ccs.calculateTemperature();
      if (!ccs.readData())  {
        eco2 = ccs.geteCO2();
        tvoc = ccs.getTVOC();
      }
      else {
        error = true;
        Serial.println("CCS811 sensor  error!");
        errorString = "CCS811 error";
        //while(1);
      }
      CCS811_last_read = nseconds;
    }
  }

  //Alarm levels
  alarm_level_3 = temp > high_temp_level_3 || temp < low_temp_level_3 || rh > high_rh_level_3  || rh < low_rh_level_3 || eco2 > co2_level_3 || tvoc > tvoc_level_3;
  alarm_level_2  = temp > high_temp_level_2 || temp < low_temp_level_2 || rh > high_rh_level_2 ||  rh < low_rh_level_2 || eco2 > co2_level_2 || tvoc > tvoc_level_2;
  alarm_level_1  = temp > high_temp_level_1 || temp < low_temp_level_1 || rh > high_rh_level_1 ||  rh < low_rh_level_1 || eco2 > co2_level_1 || tvoc > tvoc_level_1;
  alarm_level_0  = !alarm_level_3 & !alarm_level_2 & !alarm_level_2;

  //Alarm LEDS &  Alarm  Strings
  if (alarm_level_3) {
    alarm = true;
    digitalWrite(green_led,  LOW);
    digitalWrite(yellow_led, LOW);
    digitalWrite(red_led, HIGH);
    if (eco2 > co2_level_3) alarmString = "CO2 High ++";
    else if (tvoc  > tvoc_level_3) alarmString = "TVOC High ++";
    else if (rh > high_rh_level_3)  alarmString = "RH High ++";
    else if (rh < low_rh_level_3) alarmString =  "RH Low --";
    else if (temp > high_temp_level_3) alarmString = "Temp High  ++";
    else if (temp < low_temp_level_3) alarmString = "Temp Low --";
  }
  else if (alarm_level_2) {
    alarm = true;
    digitalWrite(green_led,  LOW);
    digitalWrite(yellow_led, HIGH);
    digitalWrite(red_led, LOW);
    if (eco2 > co2_level_2) alarmString = "CO2 High +";
    else if (tvoc >  tvoc_level_2) alarmString = "TVOC High +";
    else if (rh > high_rh_level_2)  alarmString = "RH High +";
    else if (rh < low_rh_level_2) alarmString =  "RH Low -";
    else if (temp > high_temp_level_2) alarmString = "Temp High  +";
    else if (temp < low_temp_level_2) alarmString = "Temp Low -";
  }
  else if (alarm_level_1) {
    alarm = true;
    digitalWrite(green_led,  LOW);
    digitalWrite(yellow_led, HIGH);
    digitalWrite(red_led, LOW);
    if (eco2 > co2_level_1)alarmString = ("CO2 High");
    else if (tvoc >  tvoc_level_1) alarmString = "TVOC High";
    else if (rh > high_rh_level_1)  alarmString = "RH High";
    else if (rh < low_rh_level_1) alarmString = "RH  Low";
    else if (temp > high_temp_level_1) alarmString = "Temp High";
    else if (temp < low_temp_level_1) alarmString = "Temp Low";
  }
  else  if (alarm_level_0) {
    alarm = false;
    digitalWrite(green_led, HIGH);
    digitalWrite(yellow_led, LOW);
    digitalWrite(red_led, LOW);
    alarmString  = "OK";
  }
  //Max and min determination
  if (temp > max_temp) max_temp  = temp;
  if (temp < min_temp) min_temp = temp;
  if (rh > max_rh) max_rh  = rh;
  if (rh < min_rh) min_rh = rh;
  if (eco2 > max_eco2) max_eco2 = eco2;
  if (eco2 < min_eco2) min_eco2 = eco2;
  if (tvoc > max_tvoc) max_tvoc = tvoc;
  if (tvoc < min_tvoc) min_tvoc = tvoc;

  //Relatorio serial
  Serial.print("Data:"  );
  serial2digits(rtc.getDay());
  Serial.print("/");
  serial2digits(rtc.getMonth());
  Serial.print("/");
  Serial.print(2000 + rtc.getYear(), DEC);
  Serial.print("  Hora:" );
  serial2digits(rtc.getHours());
  Serial.print(":");
  serial2digits(rtc.getMinutes());
  Serial.print(":");
  serial2digits(rtc.getSeconds());
  Serial.print("  ");
  Serial.print("VBat:" ); Serial.print(measuredvbat);
  Serial.print("  Temp:");   Serial.print(temp);
  Serial.print(" Humid:");   Serial.print(rh);
  Serial.print(" CO2:");   Serial.print(eco2);
  Serial.print(" ppm, TVOC:");  Serial.print(tvoc); Serial.print(" ppb:");
  Serial.print(" Status:");
  if (error)
    Serial.println(errorString);
  else if (alarm)
    Serial.println(alarmString);
  else Serial.println("OK");

  //Data display
  if (abs(nseconds - display_last_refresh  >= display_refresh_interval)) //time to display information
  {
    display.clearDisplay();//  Clean Display
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.setCursor(0, 0);
    display.println("Air Quality Analyzer");
    display.setCursor(0, 8);
    display2digits(rtc.getDay());
    display.print("/");
    display2digits(rtc.getMonth());
    display.print("/");
    display.print(2000  + rtc.getYear(), DEC);
    display.print(" ");
    display2digits(rtc.getHours());
    display.print(":");
    display2digits(rtc.getMinutes());
    /*display.print(":");
      display.print(rtc.getSeconds(), DEC);*/
    display.setCursor(0, 16);
    display.print("Vbat:");
    display.setCursor(50, 16);
    display.print(measuredvbat);  display.print(" V");
    display.setCursor(0, 24);
    display.print("Temp:");
    display.setCursor(50, 24);
    display.print(temp); display.print(" C");
    display.setCursor(0, 32);
    display.print("RH:");
    display.setCursor(50,  32);
    display.print(rh); display.print(" %");
    display.setCursor(0,  40);
    display.print("eCO2:");
    display.setCursor(50, 40);
    display.print(eco2);  display.print(" ppm");
    display.setCursor(0, 48);
    display.print("TVOC:");
    display.setCursor(50, 48);
    display.print(tvoc); display.print(" ppb");
    display.setCursor(0, 56);
    display.print("Status:");
    display.setCursor(50,  56);
    if (error) {
      display.print(errorString);
    } else if (alarm)  {
      display.print(alarmString);
    }
    else
    {
      display.print("OK");
    }
    display.display();
    display_last_refresh = nseconds;
  }
  //SD datalog
  //if (nseconds % SD_write_interval == 0) //Time to log data
  if (abs(nseconds - SD_last_write >= SD_write_interval)) //Time to log data
  {
    File logfile = SD.open(ficheiro, FILE_WRITE);
    if (logfile) {
      digitalWrite(SD_led, HIGH); //SD Write begins
      logfile2digits(rtc.getDay(),  logfile);
      logfile.print("/");
      logfile2digits(rtc.getMonth(),  logfile);
      logfile.print("/");
      logfile.print(2000 + rtc.getYear(),  DEC);
      logfile.print(",");
      logfile2digits(rtc.getHours(), logfile);
      logfile.print(":");
      logfile2digits(rtc.getMinutes(), logfile);
      logfile.print(":");
      logfile2digits(rtc.getSeconds(), logfile);
      logfile.print(",");
      logfile.print(measuredvbat, 2);
      logfile.print(",");
      logfile.print(min_temp, 2);
      logfile.print(",");
      logfile.print(max_temp,  2);
      logfile.print(",");
      logfile.print(min_rh, 2);
      logfile.print(",");
      logfile.print(max_rh, 2);
      logfile.print(",");
      logfile.print(min_eco2,  2);
      logfile.print(",");
      logfile.print(max_eco2, 2);
      logfile.print(",");
      logfile.print(min_tvoc, 2);
      logfile.print(",");
      logfile.print(max_tvoc,  2);
      logfile.print(",");
      if (error)
        logfile.println(errorString);
      else if (alarm)
        logfile.println(alarmString);
      else logfile.println("OK");
      logfile.close();
      SD_last_write = nseconds;
      digitalWrite(SD_led,  LOW); //SD Write ends
    }
    else
    {
      error = true;
      errorString  = ("logfile error");
    }
    //Max and min RESET
    max_eco2 = 0.0;
    min_eco2 = 10000;
    max_tvoc = 0.0;
    min_tvoc = 10000;
    max_temp  = 0.0;
    min_temp = 100;
    max_rh = 0.0;
    min_rh = 100;
  }
  delay(200); //don't use values higher than 1000 or nseconds won't be properly  updated
}

void display2digits(int number)// create a leading zero for  month/day/hour/minute when <10
{
  if (number >= 0 && number < 10) {
    display.write('0');
  }
  display.print(number);
}

void logfile2digits(int number, File  logfile) // create a leading zero for month/day/hour/minute when <10
{
  if  (number >= 0 && number < 10) {
    logfile.write('0');
  }
  logfile.print(number);
}

void  serial2digits(int number)// create a leading zero for month/day/hour/minute when  <10
{
  if (number >= 0 && number < 10) {
    Serial.write('0');
  }
  Serial.print(number);
}

Software version 2.0.3

arduino

This is the version 2.0.3 of the software. Has better time handling and improved display of data. Date and time now displayed on the main screen. Please inform if you have problems.

1/* Air Quality Sensor V2.0.3 2018/03/27 Luis Sousa */
2
3#include
4  <SPI.h> //Standard lib
5#include <SD.h> //author=Arduino, SparkFun version=1.2.2
6#include
7  <DHT.h>//author=Adafruit version=1.3.0
8//#include <Wire.h>
9#include <RTCZero.h>
10  //author=Arduino version=1.5.2
11#include <RTClib.h> //author=Adafruit version=1.2.1
12  
13#include <Adafruit_GFX.h> //author=Adafruit version=1.2.3
14#include <Adafruit_SSD1306.h>
15  //author=Adafruit version=1.1.2
16#include <Adafruit_CCS811.h>//author=Adafruit
17  version=1.0.0
18
19//Levels
20//temp levels
21#define low_temp_level_1 18
22#define
23  low_temp_level_2 12
24#define low_temp_level_3 8
25#define high_temp_level_1 29
26#define
27  high_temp_level_2 35
28#define high_temp_level_3 40
29//rh levels
30#define low_rh_level_1
31  40
32#define low_rh_level_2 30
33#define low_rh_level_3 20
34#define high_rh_level_1
35  70
36#define high_rh_level_2 80
37#define high_rh_level_3 90
38//co2 levels
39#define
40  co2_level_1 1000
41#define co2_level_2 1500
42#define co2_level_3 3000
43//TVOC
44  levels
45#define tvoc_level_1 100
46#define tvoc_level_2 500
47#define tvoc_level_3
48  1000
49
50//Status LEDS
51#define green_led  14
52#define yellow_led 15
53#define
54  red_led 16
55
56//OLED Display If using software SPI (the default case):
57#define
58  OLED_MOSI   6
59#define OLED_CLK   10
60#define OLED_DC    11
61#define OLED_CS
62    12
63#define OLED_RESET 5
64#define display_refresh_interval 1 //2 seconds
65  refresh
66Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
67
68//DHT
69  Sensor
70#define DHTPIN 19     // what pin DHT is connected to (19=A5 on this Board)
71#define
72  DHTTYPE DHT11   // DHT 11
73#define DHT_read_interval 3 //Read temp every X seconds
74DHT
75  dht(DHTPIN, DHTTYPE); //object dht creation
76
77//SD Card
78#define cardSelect
79  4  //SD chip select pin
80#define ficheiro "dados.csv" // nome do ficheiro de
81  dados
82//#define Serial_Header "Date,Hour,Vbat,Temp,%RH,eCO2,TVOC,STATUS"
83#define
84  SD_Header "Date,Hour,Vbat,min_Temp,Max_Temp,min_RH,Max_RH,min_eCO2,Max_eCO2,min_TVOC,Max_TVOC,STATUS"
85#define
86  SD_write_interval 300 //seconds between SD writes
87#define SD_led 8 //Green LED
88
89//RTC
90RTCZero
91  rtc;  // Create an rtc object /
92
93//Vbat read
94#define vbatpin A7    //pin
95  to read Bat Voltage
96#define vbat_read_interval 30 //seconds between vbat readings
97float
98  measuredvbat;
99
100//Set up variables using the SD utility library functions:
101Sd2Card
102  card;
103SdVolume volume;
104SdFile root;
105
106//Set up CCS811 object ccs
107Adafruit_CCS811
108  ccs;
109#define CCS811_read_interval 3 //Read data every X seconds
110
111//variable
112  declaration
113unsigned long nseconds; //seconds since start of day.
114unsigned
115  long SD_last_write = 0;
116unsigned long vbat_last_read = 0;
117unsigned long DHT_last_read
118  = 0;
119unsigned long CCS811_last_read = 0;
120unsigned long display_last_refresh
121  = 0;
122boolean error = false; //clear errors
123boolean alarm = false; //clear
124  alarms
125boolean alarm_level_0 = false;
126boolean alarm_level_1 = false;
127boolean
128  alarm_level_2 = false;
129boolean alarm_level_3 = false;
130float eco2 = 0.0;
131float
132  max_eco2 = 0.0;
133float min_eco2 = 10000;
134float tvoc = 0.0;
135float max_tvoc
136  = 0.0;
137float min_tvoc = 10000;
138float temp = 0.0;
139float max_temp = 0.0;
140float
141  min_temp = 100;
142float rh = 0.0;
143float max_rh = 0.0;
144float min_rh = 100;
145String
146  errorString = "";
147String alarmString = "";
148//byte day = 27;
149//byte
150  month = 03;
151//byte year = 18;
152//byte seconds = 00;
153//byte minutes = 00;
154//byte
155  hours = 12;
156
157void setup() {
158  pinMode(SD_led, OUTPUT);// initialize digital
159  pin 8 as an output.
160  pinMode(green_led, OUTPUT);// initialize digital pin as
161  an output.
162  pinMode(yellow_led, OUTPUT);// initialize digital pin as an output.
163
164  pinMode(red_led, OUTPUT);// initialize digital pin as an output.
165
166  //Serial
167  Port Initialization
168  Serial.begin(57600);
169  delay (300);//wait for the serial
170  to be ready
171  /*
172    while (!Serial) {
173    ; // wait for serial port to
174  connect. Needed for native USB port only
175    }
176  */
177
178  //RTC initialization
179
180  DateTime now;
181  now = (DateTime(F(__DATE__), F(__TIME__))); //Compilation time
182
183  now=now+20; //compensation for Compile + Reset time
184  rtc.begin(); // initialize
185  RTCZero
186  rtc.setTime(now.hour(), now.minute(), now.second());
187  rtc.setDate(now.day(),
188  now.month(), now.year()-2000);
189
190  //DHT Initialisation
191  dht.begin();
192
193
194  // CCS811 test
195  if (!ccs.begin()) {
196    Serial.println("Failed to start
197  CCS811 sensor! Please check your wiring.");
198    errorString = "CCS811 Error";
199
200    //while (1);
201  }
202  //calibrate CCS811 temperature sensor
203  while (!ccs.available());
204
205  temp = ccs.calculateTemperature();
206  ccs.setTempOffset(temp - 25.0);
207
208
209  //Display initialization
210  display.begin(SSD1306_SWITCHCAPVCC);// by default,
211  we'll generate the high voltage from the 3.3v line internally!
212  display.clearDisplay();
213  // Clear the buffer.
214
215  //SD Initialization and Test
216  Serial.print("\
217Initializing
218  SD card...");
219  // we'll use the initialization code from the utility libraries
220
221  // since we're just testing if the card is working!
222  if (!card.init(SPI_HALF_SPEED,
223  cardSelect)) {
224    Serial.println("initialization failed. Things to check: ");
225
226    Serial.println("* is a card inserted ? ");
227    Serial.println("* is your
228  wiring correct ? ");
229    Serial.println("* did you change the chipSelect pin
230  to match your shield or module ? ");
231    //while (1);
232    errorString = "SD
233  Card Error";
234  } else {
235    Serial.println("Wiring is correct and a card
236  is present.");
237  }
238  // print the type of card
239  Serial.println();
240
241  Serial.print("Card type :         ");
242  switch (card.type()) {
243    case
244  SD_CARD_TYPE_SD1:
245      Serial.println("SD1");
246      break;
247    case
248  SD_CARD_TYPE_SD2:
249      Serial.println("SD2");
250      break;
251    case
252  SD_CARD_TYPE_SDHC:
253      Serial.println("SDHC");
254      break;
255    default:
256
257      Serial.println("Unknown");
258  }
259  // Now we will try to open the 'volume'/'partition'
260  - it should be FAT16 or FAT32
261  if (!volume.init(card)) {
262    Serial.println("Could
263  not find FAT16 / FAT32 partition.\
264Make sure you've formatted the card");
265
266    //while (1);
267    errorString = "SD Format Error";
268  }
269  Serial.print("Clusters:
270          ");
271  Serial.println(volume.clusterCount());
272  Serial.print("Blocks
273  x Cluster:  ");
274  Serial.println(volume.blocksPerCluster());
275  Serial.print("Total
276  Blocks:      ");
277  Serial.println(volume.blocksPerCluster() * volume.clusterCount());
278
279  Serial.println();
280  // print the type and size of the first FAT-type volume
281
282  uint32_t volumesize;
283  Serial.print("Volume type is:    FAT");
284  Serial.println(volume.fatType(),
285  DEC);
286  volumesize = volume.blocksPerCluster();    // clusters are collections
287  of blocks
288  volumesize *= volume.clusterCount();       // we'll have a lot of
289  clusters
290  volumesize /= 2;                           // SD card blocks are always
291  512 bytes (2 blocks are 1KB)
292  Serial.print("Volume size (Kb):  ");
293  Serial.println(volumesize);
294
295  Serial.print("Volume size (Mb):  ");
296  volumesize /= 1024;
297  Serial.println(volumesize);
298
299  Serial.print("Volume size (Gb):  ");
300  Serial.println((float)volumesize /
301  1024.0);
302  Serial.println("\
303Files found on the card (name, date and size in
304  bytes): ");
305  root.openRoot(volume);
306  // list all files in the card with
307  date and size
308  root.ls(LS_R | LS_DATE | LS_SIZE);
309  if (!SD.begin(cardSelect))
310  {
311    errorString = ("No SD Card");
312  }
313  else {
314    File logfile
315  = SD.open(ficheiro, FILE_WRITE);
316    if (!logfile)
317      errorString = ("File
318  Error");
319    else {
320      Serial.print("Gravando em: ");
321      Serial.println(ficheiro);
322
323      logfile.println(SD_Header);
324      logfile.close();
325    }
326  }
327}
328
329void
330  loop() {
331  //How many seconds since 0H (start of day)
332  nseconds = 3600 *
333  rtc.getHours() + 60 * rtc.getMinutes() + rtc.getSeconds();
334
335  //measure Vbat
336
337  if (abs(nseconds - vbat_last_read >= vbat_read_interval)) //time to read vbat
338
339  {
340    measuredvbat = analogRead(vbatpin);
341    measuredvbat *= 2; // we divided
342  by 2, so multiply back
343    measuredvbat *= 3.3; // Multiply by 3.3V, our reference
344  voltage
345    measuredvbat /= 1024; // convert to voltage
346    vbat_last_read
347  = nseconds;
348  }
349  // Reading temperature and humidity
350  //if (nseconds
351  % DHT_read_interval == 0) //Time to read temp
352  if (abs(nseconds - DHT_last_read
353  >= DHT_read_interval)) //time to read DHT
354  {
355    rh = dht.readHumidity();
356
357    temp = dht.readTemperature();  // Read temperature as Celsius (the default)
358
359    float f = dht.readTemperature(true);   // Read temperature as Fahrenheit (isFahrenheit
360  = true)
361
362    if (isnan(rh) || isnan(temp) || isnan(f)) {
363      Serial.println("Failed
364  to read from DHT sensor!");// Check if any reads failed and exit early (to try
365  again).
366      error = true;
367      errorString = ("DHT Error");
368      //return;
369
370    }
371    DHT_last_read = nseconds;
372  }
373  // Reading eCO2 & TVOC
374  //if
375  (nseconds % CCS811_read_interval == 0) //Time to read data
376  if (abs(nseconds
377  - CCS811_last_read >= CCS811_read_interval)) //time to read CCS811
378  {
379    if
380  (ccs.available()) {
381      //temp = ccs.calculateTemperature();
382      if (!ccs.readData())
383  {
384        eco2 = ccs.geteCO2();
385        tvoc = ccs.getTVOC();
386      }
387
388      else {
389        error = true;
390        Serial.println("CCS811 sensor
391  error!");
392        errorString = "CCS811 error";
393        //while(1);
394
395      }
396      CCS811_last_read = nseconds;
397    }
398  }
399
400  //Alarm levels
401
402  alarm_level_3 = temp > high_temp_level_3 || temp < low_temp_level_3 || rh > high_rh_level_3
403  || rh < low_rh_level_3 || eco2 > co2_level_3 || tvoc > tvoc_level_3;
404  alarm_level_2
405  = temp > high_temp_level_2 || temp < low_temp_level_2 || rh > high_rh_level_2 ||
406  rh < low_rh_level_2 || eco2 > co2_level_2 || tvoc > tvoc_level_2;
407  alarm_level_1
408  = temp > high_temp_level_1 || temp < low_temp_level_1 || rh > high_rh_level_1 ||
409  rh < low_rh_level_1 || eco2 > co2_level_1 || tvoc > tvoc_level_1;
410  alarm_level_0
411  = !alarm_level_3 & !alarm_level_2 & !alarm_level_2;
412
413  //Alarm LEDS &  Alarm
414  Strings
415  if (alarm_level_3) {
416    alarm = true;
417    digitalWrite(green_led,
418  LOW);
419    digitalWrite(yellow_led, LOW);
420    digitalWrite(red_led, HIGH);
421
422    if (eco2 > co2_level_3) alarmString = "CO2 High ++";
423    else if (tvoc
424  > tvoc_level_3) alarmString = "TVOC High ++";
425    else if (rh > high_rh_level_3)
426  alarmString = "RH High ++";
427    else if (rh < low_rh_level_3) alarmString =
428  "RH Low --";
429    else if (temp > high_temp_level_3) alarmString = "Temp High
430  ++";
431    else if (temp < low_temp_level_3) alarmString = "Temp Low --";
432
433  }
434  else if (alarm_level_2) {
435    alarm = true;
436    digitalWrite(green_led,
437  LOW);
438    digitalWrite(yellow_led, HIGH);
439    digitalWrite(red_led, LOW);
440
441    if (eco2 > co2_level_2) alarmString = "CO2 High +";
442    else if (tvoc >
443  tvoc_level_2) alarmString = "TVOC High +";
444    else if (rh > high_rh_level_2)
445  alarmString = "RH High +";
446    else if (rh < low_rh_level_2) alarmString =
447  "RH Low -";
448    else if (temp > high_temp_level_2) alarmString = "Temp High
449  +";
450    else if (temp < low_temp_level_2) alarmString = "Temp Low -";
451
452  }
453  else if (alarm_level_1) {
454    alarm = true;
455    digitalWrite(green_led,
456  LOW);
457    digitalWrite(yellow_led, HIGH);
458    digitalWrite(red_led, LOW);
459
460    if (eco2 > co2_level_1)alarmString = ("CO2 High");
461    else if (tvoc >
462  tvoc_level_1) alarmString = "TVOC High";
463    else if (rh > high_rh_level_1)
464  alarmString = "RH High";
465    else if (rh < low_rh_level_1) alarmString = "RH
466  Low";
467    else if (temp > high_temp_level_1) alarmString = "Temp High";
468
469    else if (temp < low_temp_level_1) alarmString = "Temp Low";
470  }
471  else
472  if (alarm_level_0) {
473    alarm = false;
474    digitalWrite(green_led, HIGH);
475
476    digitalWrite(yellow_led, LOW);
477    digitalWrite(red_led, LOW);
478    alarmString
479  = "OK";
480  }
481  //Max and min determination
482  if (temp > max_temp) max_temp
483  = temp;
484  if (temp < min_temp) min_temp = temp;
485  if (rh > max_rh) max_rh
486  = rh;
487  if (rh < min_rh) min_rh = rh;
488  if (eco2 > max_eco2) max_eco2 = eco2;
489
490  if (eco2 < min_eco2) min_eco2 = eco2;
491  if (tvoc > max_tvoc) max_tvoc = tvoc;
492
493  if (tvoc < min_tvoc) min_tvoc = tvoc;
494
495  //Relatorio serial
496  Serial.print("Data:"
497  );
498  serial2digits(rtc.getDay());
499  Serial.print("/");
500  serial2digits(rtc.getMonth());
501
502  Serial.print("/");
503  Serial.print(2000 + rtc.getYear(), DEC);
504  Serial.print("
505  Hora:" );
506  serial2digits(rtc.getHours());
507  Serial.print(":");
508  serial2digits(rtc.getMinutes());
509
510  Serial.print(":");
511  serial2digits(rtc.getSeconds());
512  Serial.print("
513  ");
514  Serial.print("VBat:" ); Serial.print(measuredvbat);
515  Serial.print("
516  Temp:");   Serial.print(temp);
517  Serial.print(" Humid:");   Serial.print(rh);
518
519  Serial.print(" CO2:");   Serial.print(eco2);
520  Serial.print(" ppm, TVOC:");
521  Serial.print(tvoc); Serial.print(" ppb:");
522  Serial.print(" Status:");
523
524  if (error)
525    Serial.println(errorString);
526  else if (alarm)
527    Serial.println(alarmString);
528
529  else Serial.println("OK");
530
531  //Data display
532  if (abs(nseconds - display_last_refresh
533  >= display_refresh_interval)) //time to display information
534  {
535    display.clearDisplay();//
536  Clean Display
537    display.setTextSize(1);
538    display.setTextColor(WHITE);
539
540    display.setCursor(0, 0);
541    display.println("Air Quality Analyzer");
542
543    display.setCursor(0, 8);
544    display2digits(rtc.getDay());
545    display.print("/");
546
547    display2digits(rtc.getMonth());
548    display.print("/");
549    display.print(2000
550  + rtc.getYear(), DEC);
551    display.print(" ");
552    display2digits(rtc.getHours());
553
554    display.print(":");
555    display2digits(rtc.getMinutes());
556    /*display.print(":");
557
558      display.print(rtc.getSeconds(), DEC);*/
559    display.setCursor(0, 16);
560
561    display.print("Vbat:");
562    display.setCursor(50, 16);
563    display.print(measuredvbat);
564  display.print(" V");
565    display.setCursor(0, 24);
566    display.print("Temp:");
567
568    display.setCursor(50, 24);
569    display.print(temp); display.print(" C");
570
571    display.setCursor(0, 32);
572    display.print("RH:");
573    display.setCursor(50,
574  32);
575    display.print(rh); display.print(" %");
576    display.setCursor(0,
577  40);
578    display.print("eCO2:");
579    display.setCursor(50, 40);
580    display.print(eco2);
581  display.print(" ppm");
582    display.setCursor(0, 48);
583    display.print("TVOC:");
584
585    display.setCursor(50, 48);
586    display.print(tvoc); display.print(" ppb");
587
588    display.setCursor(0, 56);
589    display.print("Status:");
590    display.setCursor(50,
591  56);
592    if (error) {
593      display.print(errorString);
594    } else if (alarm)
595  {
596      display.print(alarmString);
597    }
598    else
599    {
600      display.print("OK");
601
602    }
603    display.display();
604    display_last_refresh = nseconds;
605  }
606
607  //SD datalog
608  //if (nseconds % SD_write_interval == 0) //Time to log data
609
610  if (abs(nseconds - SD_last_write >= SD_write_interval)) //Time to log data
611
612  {
613    File logfile = SD.open(ficheiro, FILE_WRITE);
614    if (logfile) {
615
616      digitalWrite(SD_led, HIGH); //SD Write begins
617      logfile2digits(rtc.getDay(),
618  logfile);
619      logfile.print("/");
620      logfile2digits(rtc.getMonth(),
621  logfile);
622      logfile.print("/");
623      logfile.print(2000 + rtc.getYear(),
624  DEC);
625      logfile.print(",");
626      logfile2digits(rtc.getHours(), logfile);
627
628      logfile.print(":");
629      logfile2digits(rtc.getMinutes(), logfile);
630
631      logfile.print(":");
632      logfile2digits(rtc.getSeconds(), logfile);
633
634      logfile.print(",");
635      logfile.print(measuredvbat, 2);
636      logfile.print(",");
637
638      logfile.print(min_temp, 2);
639      logfile.print(",");
640      logfile.print(max_temp,
641  2);
642      logfile.print(",");
643      logfile.print(min_rh, 2);
644      logfile.print(",");
645
646      logfile.print(max_rh, 2);
647      logfile.print(",");
648      logfile.print(min_eco2,
649  2);
650      logfile.print(",");
651      logfile.print(max_eco2, 2);
652      logfile.print(",");
653
654      logfile.print(min_tvoc, 2);
655      logfile.print(",");
656      logfile.print(max_tvoc,
657  2);
658      logfile.print(",");
659      if (error)
660        logfile.println(errorString);
661
662      else if (alarm)
663        logfile.println(alarmString);
664      else logfile.println("OK");
665
666      logfile.close();
667      SD_last_write = nseconds;
668      digitalWrite(SD_led,
669  LOW); //SD Write ends
670    }
671    else
672    {
673      error = true;
674      errorString
675  = ("logfile error");
676    }
677    //Max and min RESET
678    max_eco2 = 0.0;
679
680    min_eco2 = 10000;
681    max_tvoc = 0.0;
682    min_tvoc = 10000;
683    max_temp
684  = 0.0;
685    min_temp = 100;
686    max_rh = 0.0;
687    min_rh = 100;
688  }
689
690  delay(200); //don't use values higher than 1000 or nseconds won't be properly
691  updated
692}
693
694void display2digits(int number)// create a leading zero for
695  month/day/hour/minute when <10
696{
697  if (number >= 0 && number < 10) {
698    display.write('0');
699
700  }
701  display.print(number);
702}
703
704void logfile2digits(int number, File
705  logfile) // create a leading zero for month/day/hour/minute when <10
706{
707  if
708  (number >= 0 && number < 10) {
709    logfile.write('0');
710  }
711  logfile.print(number);
712}
713
714void
715  serial2digits(int number)// create a leading zero for month/day/hour/minute when
716  <10
717{
718  if (number >= 0 && number < 10) {
719    Serial.write('0');
720  }
721
722  Serial.print(number);
723}
724

/* Air Quality Sensor V2.0.3 2018/03/27 Luis Sousa */

#include
  <SPI.h> //Standard lib
#include <SD.h> //author=Arduino, SparkFun version=1.2.2
#include
  <DHT.h>//author=Adafruit version=1.3.0
//#include <Wire.h>
#include <RTCZero.h>
  //author=Arduino version=1.5.2
#include <RTClib.h> //author=Adafruit version=1.2.1
  
#include <Adafruit_GFX.h> //author=Adafruit version=1.2.3
#include <Adafruit_SSD1306.h>
  //author=Adafruit version=1.1.2
#include <Adafruit_CCS811.h>//author=Adafruit
  version=1.0.0

//Levels
//temp levels
#define low_temp_level_1 18
#define
  low_temp_level_2 12
#define low_temp_level_3 8
#define high_temp_level_1 29
#define
  high_temp_level_2 35
#define high_temp_level_3 40
//rh levels
#define low_rh_level_1
  40
#define low_rh_level_2 30
#define low_rh_level_3 20
#define high_rh_level_1
  70
#define high_rh_level_2 80
#define high_rh_level_3 90
//co2 levels
#define
  co2_level_1 1000
#define co2_level_2 1500
#define co2_level_3 3000
//TVOC
  levels
#define tvoc_level_1 100
#define tvoc_level_2 500
#define tvoc_level_3
  1000

//Status LEDS
#define green_led  14
#define yellow_led 15
#define
  red_led 16

//OLED Display If using software SPI (the default case):
#define
  OLED_MOSI   6
#define OLED_CLK   10
#define OLED_DC    11
#define OLED_CS
    12
#define OLED_RESET 5
#define display_refresh_interval 1 //2 seconds
  refresh
Adafruit_SSD1306 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);

//DHT
  Sensor
#define DHTPIN 19     // what pin DHT is connected to (19=A5 on this Board)
#define
  DHTTYPE DHT11   // DHT 11
#define DHT_read_interval 3 //Read temp every X seconds
DHT
  dht(DHTPIN, DHTTYPE); //object dht creation

//SD Card
#define cardSelect
  4  //SD chip select pin
#define ficheiro "dados.csv" // nome do ficheiro de
  dados
//#define Serial_Header "Date,Hour,Vbat,Temp,%RH,eCO2,TVOC,STATUS"
#define
  SD_Header "Date,Hour,Vbat,min_Temp,Max_Temp,min_RH,Max_RH,min_eCO2,Max_eCO2,min_TVOC,Max_TVOC,STATUS"
#define
  SD_write_interval 300 //seconds between SD writes
#define SD_led 8 //Green LED

//RTC
RTCZero
  rtc;  // Create an rtc object /

//Vbat read
#define vbatpin A7    //pin
  to read Bat Voltage
#define vbat_read_interval 30 //seconds between vbat readings
float
  measuredvbat;

//Set up variables using the SD utility library functions:
Sd2Card
  card;
SdVolume volume;
SdFile root;

//Set up CCS811 object ccs
Adafruit_CCS811
  ccs;
#define CCS811_read_interval 3 //Read data every X seconds

//variable
  declaration
unsigned long nseconds; //seconds since start of day.
unsigned
  long SD_last_write = 0;
unsigned long vbat_last_read = 0;
unsigned long DHT_last_read
  = 0;
unsigned long CCS811_last_read = 0;
unsigned long display_last_refresh
  = 0;
boolean error = false; //clear errors
boolean alarm = false; //clear
  alarms
boolean alarm_level_0 = false;
boolean alarm_level_1 = false;
boolean
  alarm_level_2 = false;
boolean alarm_level_3 = false;
float eco2 = 0.0;
float
  max_eco2 = 0.0;
float min_eco2 = 10000;
float tvoc = 0.0;
float max_tvoc
  = 0.0;
float min_tvoc = 10000;
float temp = 0.0;
float max_temp = 0.0;
float
  min_temp = 100;
float rh = 0.0;
float max_rh = 0.0;
float min_rh = 100;
String
  errorString = "";
String alarmString = "";
//byte day = 27;
//byte
  month = 03;
//byte year = 18;
//byte seconds = 00;
//byte minutes = 00;
//byte
  hours = 12;

void setup() {
  pinMode(SD_led, OUTPUT);// initialize digital
  pin 8 as an output.
  pinMode(green_led, OUTPUT);// initialize digital pin as
  an output.
  pinMode(yellow_led, OUTPUT);// initialize digital pin as an output.

  pinMode(red_led, OUTPUT);// initialize digital pin as an output.

  //Serial
  Port Initialization
  Serial.begin(57600);
  delay (300);//wait for the serial
  to be ready
  /*
    while (!Serial) {
    ; // wait for serial port to
  connect. Needed for native USB port only
    }
  */

  //RTC initialization

  DateTime now;
  now = (DateTime(F(__DATE__), F(__TIME__))); //Compilation time

  now=now+20; //compensation for Compile + Reset time
  rtc.begin(); // initialize
  RTCZero
  rtc.setTime(now.hour(), now.minute(), now.second());
  rtc.setDate(now.day(),
  now.month(), now.year()-2000);

  //DHT Initialisation
  dht.begin();


  // CCS811 test
  if (!ccs.begin()) {
    Serial.println("Failed to start
  CCS811 sensor! Please check your wiring.");
    errorString = "CCS811 Error";

    //while (1);
  }
  //calibrate CCS811 temperature sensor
  while (!ccs.available());

  temp = ccs.calculateTemperature();
  ccs.setTempOffset(temp - 25.0);


  //Display initialization
  display.begin(SSD1306_SWITCHCAPVCC);// by default,
  we'll generate the high voltage from the 3.3v line internally!
  display.clearDisplay();
  // Clear the buffer.

  //SD Initialization and Test
  Serial.print("\
Initializing
  SD card...");
  // we'll use the initialization code from the utility libraries

  // since we're just testing if the card is working!
  if (!card.init(SPI_HALF_SPEED,
  cardSelect)) {
    Serial.println("initialization failed. Things to check: ");

    Serial.println("* is a card inserted ? ");
    Serial.println("* is your
  wiring correct ? ");
    Serial.println("* did you change the chipSelect pin
  to match your shield or module ? ");
    //while (1);
    errorString = "SD
  Card Error";
  } else {
    Serial.println("Wiring is correct and a card
  is present.");
  }
  // print the type of card
  Serial.println();

  Serial.print("Card type :         ");
  switch (card.type()) {
    case
  SD_CARD_TYPE_SD1:
      Serial.println("SD1");
      break;
    case
  SD_CARD_TYPE_SD2:
      Serial.println("SD2");
      break;
    case
  SD_CARD_TYPE_SDHC:
      Serial.println("SDHC");
      break;
    default:

      Serial.println("Unknown");
  }
  // Now we will try to open the 'volume'/'partition'
  - it should be FAT16 or FAT32
  if (!volume.init(card)) {
    Serial.println("Could
  not find FAT16 / FAT32 partition.\
Make sure you've formatted the card");

    //while (1);
    errorString = "SD Format Error";
  }
  Serial.print("Clusters:
          ");
  Serial.println(volume.clusterCount());
  Serial.print("Blocks
  x Cluster:  ");
  Serial.println(volume.blocksPerCluster());
  Serial.print("Total
  Blocks:      ");
  Serial.println(volume.blocksPerCluster() * volume.clusterCount());

  Serial.println();
  // print the type and size of the first FAT-type volume

  uint32_t volumesize;
  Serial.print("Volume type is:    FAT");
  Serial.println(volume.fatType(),
  DEC);
  volumesize = volume.blocksPerCluster();    // clusters are collections
  of blocks
  volumesize *= volume.clusterCount();       // we'll have a lot of
  clusters
  volumesize /= 2;                           // SD card blocks are always
  512 bytes (2 blocks are 1KB)
  Serial.print("Volume size (Kb):  ");
  Serial.println(volumesize);

  Serial.print("Volume size (Mb):  ");
  volumesize /= 1024;
  Serial.println(volumesize);

  Serial.print("Volume size (Gb):  ");
  Serial.println((float)volumesize /
  1024.0);
  Serial.println("\
Files found on the card (name, date and size in
  bytes): ");
  root.openRoot(volume);
  // list all files in the card with
  date and size
  root.ls(LS_R | LS_DATE | LS_SIZE);
  if (!SD.begin(cardSelect))
  {
    errorString = ("No SD Card");
  }
  else {
    File logfile
  = SD.open(ficheiro, FILE_WRITE);
    if (!logfile)
      errorString = ("File
  Error");
    else {
      Serial.print("Gravando em: ");
      Serial.println(ficheiro);

      logfile.println(SD_Header);
      logfile.close();
    }
  }
}

void
  loop() {
  //How many seconds since 0H (start of day)
  nseconds = 3600 *
  rtc.getHours() + 60 * rtc.getMinutes() + rtc.getSeconds();

  //measure Vbat

  if (abs(nseconds - vbat_last_read >= vbat_read_interval)) //time to read vbat

  {
    measuredvbat = analogRead(vbatpin);
    measuredvbat *= 2; // we divided
  by 2, so multiply back
    measuredvbat *= 3.3; // Multiply by 3.3V, our reference
  voltage
    measuredvbat /= 1024; // convert to voltage
    vbat_last_read
  = nseconds;
  }
  // Reading temperature and humidity
  //if (nseconds
  % DHT_read_interval == 0) //Time to read temp
  if (abs(nseconds - DHT_last_read
  >= DHT_read_interval)) //time to read DHT
  {
    rh = dht.readHumidity();

    temp = dht.readTemperature();  // Read temperature as Celsius (the default)

    float f = dht.readTemperature(true);   // Read temperature as Fahrenheit (isFahrenheit
  = true)

    if (isnan(rh) || isnan(temp) || isnan(f)) {
      Serial.println("Failed
  to read from DHT sensor!");// Check if any reads failed and exit early (to try
  again).
      error = true;
      errorString = ("DHT Error");
      //return;

    }
    DHT_last_read = nseconds;
  }
  // Reading eCO2 & TVOC
  //if
  (nseconds % CCS811_read_interval == 0) //Time to read data
  if (abs(nseconds
  - CCS811_last_read >= CCS811_read_interval)) //time to read CCS811
  {
    if
  (ccs.available()) {
      //temp = ccs.calculateTemperature();
      if (!ccs.readData())
  {
        eco2 = ccs.geteCO2();
        tvoc = ccs.getTVOC();
      }

      else {
        error = true;
        Serial.println("CCS811 sensor
  error!");
        errorString = "CCS811 error";
        //while(1);

      }
      CCS811_last_read = nseconds;
    }
  }

  //Alarm levels

  alarm_level_3 = temp > high_temp_level_3 || temp < low_temp_level_3 || rh > high_rh_level_3
  || rh < low_rh_level_3 || eco2 > co2_level_3 || tvoc > tvoc_level_3;
  alarm_level_2
  = temp > high_temp_level_2 || temp < low_temp_level_2 || rh > high_rh_level_2 ||
  rh < low_rh_level_2 || eco2 > co2_level_2 || tvoc > tvoc_level_2;
  alarm_level_1
  = temp > high_temp_level_1 || temp < low_temp_level_1 || rh > high_rh_level_1 ||
  rh < low_rh_level_1 || eco2 > co2_level_1 || tvoc > tvoc_level_1;
  alarm_level_0
  = !alarm_level_3 & !alarm_level_2 & !alarm_level_2;

  //Alarm LEDS &  Alarm
  Strings
  if (alarm_level_3) {
    alarm = true;
    digitalWrite(green_led,
  LOW);
    digitalWrite(yellow_led, LOW);
    digitalWrite(red_led, HIGH);

    if (eco2 > co2_level_3) alarmString = "CO2 High ++";
    else if (tvoc
  > tvoc_level_3) alarmString = "TVOC High ++";
    else if (rh > high_rh_level_3)
  alarmString = "RH High ++";
    else if (rh < low_rh_level_3) alarmString =
  "RH Low --";
    else if (temp > high_temp_level_3) alarmString = "Temp High
  ++";
    else if (temp < low_temp_level_3) alarmString = "Temp Low --";

  }
  else if (alarm_level_2) {
    alarm = true;
    digitalWrite(green_led,
  LOW);
    digitalWrite(yellow_led, HIGH);
    digitalWrite(red_led, LOW);

    if (eco2 > co2_level_2) alarmString = "CO2 High +";
    else if (tvoc >
  tvoc_level_2) alarmString = "TVOC High +";
    else if (rh > high_rh_level_2)
  alarmString = "RH High +";
    else if (rh < low_rh_level_2) alarmString =
  "RH Low -";
    else if (temp > high_temp_level_2) alarmString = "Temp High
  +";
    else if (temp < low_temp_level_2) alarmString = "Temp Low -";

  }
  else if (alarm_level_1) {
    alarm = true;
    digitalWrite(green_led,
  LOW);
    digitalWrite(yellow_led, HIGH);
    digitalWrite(red_led, LOW);

    if (eco2 > co2_level_1)alarmString = ("CO2 High");
    else if (tvoc >
  tvoc_level_1) alarmString = "TVOC High";
    else if (rh > high_rh_level_1)
  alarmString = "RH High";
    else if (rh < low_rh_level_1) alarmString = "RH
  Low";
    else if (temp > high_temp_level_1) alarmString = "Temp High";

    else if (temp < low_temp_level_1) alarmString = "Temp Low";
  }
  else
  if (alarm_level_0) {
    alarm = false;
    digitalWrite(green_led, HIGH);

    digitalWrite(yellow_led, LOW);
    digitalWrite(red_led, LOW);
    alarmString
  = "OK";
  }
  //Max and min determination
  if (temp > max_temp) max_temp
  = temp;
  if (temp < min_temp) min_temp = temp;
  if (rh > max_rh) max_rh
  = rh;
  if (rh < min_rh) min_rh = rh;
  if (eco2 > max_eco2) max_eco2 = eco2;

  if (eco2 < min_eco2) min_eco2 = eco2;
  if (tvoc > max_tvoc) max_tvoc = tvoc;

  if (tvoc < min_tvoc) min_tvoc = tvoc;

  //Relatorio serial
  Serial.print("Data:"
  );
  serial2digits(rtc.getDay());
  Serial.print("/");
  serial2digits(rtc.getMonth());

  Serial.print("/");
  Serial.print(2000 + rtc.getYear(), DEC);
  Serial.print("
  Hora:" );
  serial2digits(rtc.getHours());
  Serial.print(":");
  serial2digits(rtc.getMinutes());

  Serial.print(":");
  serial2digits(rtc.getSeconds());
  Serial.print("
  ");
  Serial.print("VBat:" ); Serial.print(measuredvbat);
  Serial.print("
  Temp:");   Serial.print(temp);
  Serial.print(" Humid:");   Serial.print(rh);

  Serial.print(" CO2:");   Serial.print(eco2);
  Serial.print(" ppm, TVOC:");
  Serial.print(tvoc); Serial.print(" ppb:");
  Serial.print(" Status:");

  if (error)
    Serial.println(errorString);
  else if (alarm)
    Serial.println(alarmString);

  else Serial.println("OK");

  //Data display
  if (abs(nseconds - display_last_refresh
  >= display_refresh_interval)) //time to display information
  {
    display.clearDisplay();//
  Clean Display
    display.setTextSize(1);
    display.setTextColor(WHITE);

    display.setCursor(0, 0);
    display.println("Air Quality Analyzer");

    display.setCursor(0, 8);
    display2digits(rtc.getDay());
    display.print("/");

    display2digits(rtc.getMonth());
    display.print("/");
    display.print(2000
  + rtc.getYear(), DEC);
    display.print(" ");
    display2digits(rtc.getHours());

    display.print(":");
    display2digits(rtc.getMinutes());
    /*display.print(":");

      display.print(rtc.getSeconds(), DEC);*/
    display.setCursor(0, 16);

    display.print("Vbat:");
    display.setCursor(50, 16);
    display.print(measuredvbat);
  display.print(" V");
    display.setCursor(0, 24);
    display.print("Temp:");

    display.setCursor(50, 24);
    display.print(temp); display.print(" C");

    display.setCursor(0, 32);
    display.print("RH:");
    display.setCursor(50,
  32);
    display.print(rh); display.print(" %");
    display.setCursor(0,
  40);
    display.print("eCO2:");
    display.setCursor(50, 40);
    display.print(eco2);
  display.print(" ppm");
    display.setCursor(0, 48);
    display.print("TVOC:");

    display.setCursor(50, 48);
    display.print(tvoc); display.print(" ppb");

    display.setCursor(0, 56);
    display.print("Status:");
    display.setCursor(50,
  56);
    if (error) {
      display.print(errorString);
    } else if (alarm)
  {
      display.print(alarmString);
    }
    else
    {
      display.print("OK");

    }
    display.display();
    display_last_refresh = nseconds;
  }

  //SD datalog
  //if (nseconds % SD_write_interval == 0) //Time to log data

  if (abs(nseconds - SD_last_write >= SD_write_interval)) //Time to log data

  {
    File logfile = SD.open(ficheiro, FILE_WRITE);
    if (logfile) {

      digitalWrite(SD_led, HIGH); //SD Write begins
      logfile2digits(rtc.getDay(),
  logfile);
      logfile.print("/");
      logfile2digits(rtc.getMonth(),
  logfile);
      logfile.print("/");
      logfile.print(2000 + rtc.getYear(),
  DEC);
      logfile.print(",");
      logfile2digits(rtc.getHours(), logfile);

      logfile.print(":");
      logfile2digits(rtc.getMinutes(), logfile);

      logfile.print(":");
      logfile2digits(rtc.getSeconds(), logfile);

      logfile.print(",");
      logfile.print(measuredvbat, 2);
      logfile.print(",");

      logfile.print(min_temp, 2);
      logfile.print(",");
      logfile.print(max_temp,
  2);
      logfile.print(",");
      logfile.print(min_rh, 2);
      logfile.print(",");

      logfile.print(max_rh, 2);
      logfile.print(",");
      logfile.print(min_eco2,
  2);
      logfile.print(",");
      logfile.print(max_eco2, 2);
      logfile.print(",");

      logfile.print(min_tvoc, 2);
      logfile.print(",");
      logfile.print(max_tvoc,
  2);
      logfile.print(",");
      if (error)
        logfile.println(errorString);

      else if (alarm)
        logfile.println(alarmString);
      else logfile.println("OK");

      logfile.close();
      SD_last_write = nseconds;
      digitalWrite(SD_led,
  LOW); //SD Write ends
    }
    else
    {
      error = true;
      errorString
  = ("logfile error");
    }
    //Max and min RESET
    max_eco2 = 0.0;

    min_eco2 = 10000;
    max_tvoc = 0.0;
    min_tvoc = 10000;
    max_temp
  = 0.0;
    min_temp = 100;
    max_rh = 0.0;
    min_rh = 100;
  }

  delay(200); //don't use values higher than 1000 or nseconds won't be properly
  updated
}

void display2digits(int number)// create a leading zero for
  month/day/hour/minute when <10
{
  if (number >= 0 && number < 10) {
    display.write('0');

  }
  display.print(number);
}

void logfile2digits(int number, File
  logfile) // create a leading zero for month/day/hour/minute when <10
{
  if
  (number >= 0 && number < 10) {
    logfile.write('0');
  }
  logfile.print(number);
}

void
  serial2digits(int number)// create a leading zero for month/day/hour/minute when
  <10
{
  if (number >= 0 && number < 10) {
    Serial.write('0');
  }

  Serial.print(number);
}

Downloadable files

Air Quality Analyzer Connections V2.0

This is the second version of the Air Quality Analyzer Connections. Now we have 3 LEDs to display 3 levels of alarm, and a Sby/On switch. Also DHT11 sensor is connected to a new pin (A5) to avoid some instability caused by pin 13 internal LED circuit.

Air Quality Analyzer Connections V2.0

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