airingbutler.ino

   1 #include <SoftwareSerial.h>
   2 #include <LiquidCrystal.h>
   3 #include "MHZ19.h"
   4
   5 const int rx_pin = 2; // connect to TX on MHZ19
   6 const int tx_pin = 3; // connect to RX on MHZ19
   7
   8 const int led_green_pin  = 4;
   9 const int led_yellow_pin = 5;
  10 const int led_red_pin    = 6;
  11
  12 const int buzzer_pin = 13;
  13
  14 const int co2_warning_thr = 1000;
  15 const int co2_alarm_thr   = 1500;
  16
  17 MHZ19 mhz19 = MHZ19(rx_pin,tx_pin);
  18 LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
  19
  20 unsigned long time;
  21 int co2 = 0;
  22 int temp = 0;
  23 int lastppm = 0;
  24
  25
  26 void setup()
  27 {
  28         Serial.begin(115200);
  29         Serial.println("Time,CO2,Temp");
  30
  31         // MH-Z19
  32         mhz19.begin(rx_pin, tx_pin);
  33
  34         // LCD
  35         lcd.begin(16,2);
  36         lcd.setCursor(0,0);
  37         lcd.print("Airing Butler");
  38         lcd.setCursor(0,1);
  39         lcd.print("says hello!");
  40
  41         // LEDs + buzzer
  42         pinMode(led_green_pin, OUTPUT);
  43         pinMode(led_yellow_pin, OUTPUT);
  44         pinMode(led_red_pin, OUTPUT);
  45         pinMode(buzzer_pin, OUTPUT);
  46         digitalWrite(led_green_pin, HIGH);
  47         delay(500);
  48         digitalWrite(led_green_pin, LOW);
  49         digitalWrite(led_yellow_pin, HIGH);
  50         delay(500);
  51         digitalWrite(led_yellow_pin, LOW);
  52         digitalWrite(led_red_pin, HIGH);
  53         delay(500);
  54         digitalWrite(led_red_pin, LOW);
  55         digitalWrite(buzzer_pin, HIGH);
  56         delay(200);
  57         digitalWrite(buzzer_pin, LOW);
  58
  59         lcd.clear();
  60 }
  61
  62
  63 void loop()
  64 {
  65         time = millis();
  66         measurement_t m = mhz19.getMeasurement();
  67         co2 = m.co2_ppm;
  68         temp = m.temperature;
  69
  70         Serial.print(time);
  71         Serial.print(",");
  72         Serial.print(co2);
  73         Serial.print(",");
  74         Serial.println(temp);
  75
  76         digitalWrite(led_red_pin, co2 >= co2_alarm_thr);
  77         digitalWrite(led_yellow_pin, co2 >= co2_warning_thr && co2 < co2_alarm_thr);
  78         digitalWrite(led_green_pin, co2 < co2_warning_thr);
  79
  80         if (co2 >= co2_alarm_thr && lastppm < co2_alarm_thr) {
  81                 digitalWrite(buzzer_pin, HIGH);
  82                 delay(100);
  83                 digitalWrite(buzzer_pin, LOW);
  84                 delay(100);
  85                 digitalWrite(buzzer_pin, HIGH);
  86                 delay(100);
  87                 digitalWrite(buzzer_pin, LOW);
  88                 delay(100);
  89                 digitalWrite(buzzer_pin, HIGH);
  90                 delay(100);
  91                 digitalWrite(buzzer_pin, LOW);
  92         }
  93
  94         if (co2 >= co2_warning_thr && lastppm < co2_warning_thr) {
  95                 digitalWrite(buzzer_pin, HIGH);
  96                 delay(500);
  97                 digitalWrite(buzzer_pin, LOW);
  98         }
  99
 100         lcd.setCursor(0, 0);
 101         lcd.print("CO2: ");
 102         lcd.print(co2);
 103         lcd.print(" ppm         ");
 104
 105         lastppm = co2;
 106         delay(5000);
 107 }