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 lastppm = 0;
  22
  23
  24 void setup()
  25 {
  26         Serial.begin(115200);
  27         Serial.println("Time,CO2,Temp");
  28
  29         // MH-Z19
  30         mhz19.begin(rx_pin, tx_pin);
  31
  32         // LCD
  33         lcd.begin(16,2);
  34         lcd.setCursor(0,0);
  35         lcd.print("Airing Butler");
  36         lcd.setCursor(0,1);
  37         lcd.print("says hello!");
  38
  39         // LEDs + buzzer
  40         pinMode(led_green_pin, OUTPUT);
  41         pinMode(led_yellow_pin, OUTPUT);
  42         pinMode(led_red_pin, OUTPUT);
  43         pinMode(buzzer_pin, OUTPUT);
  44         digitalWrite(led_green_pin, HIGH);
  45         delay(500);
  46         digitalWrite(led_green_pin, LOW);
  47         digitalWrite(led_yellow_pin, HIGH);
  48         delay(500);
  49         digitalWrite(led_yellow_pin, LOW);
  50         digitalWrite(led_red_pin, HIGH);
  51         delay(500);
  52         digitalWrite(led_red_pin, LOW);
  53         digitalWrite(buzzer_pin, HIGH);
  54         delay(200);
  55         digitalWrite(buzzer_pin, LOW);
  56
  57         lcd.clear();
  58 }
  59
  60
  61 void loop()
  62 {
  63         time = millis();
  64         measurement_t m = mhz19.getMeasurement();
  65
  66         Serial.print(time);
  67         Serial.print(",");
  68         Serial.print(m.co2_ppm);
  69         Serial.print(",");
  70         Serial.println(m.temperature);
  71
  72         digitalWrite(led_red_pin, m.co2_ppm >= co2_alarm_thr);
  73         digitalWrite(led_yellow_pin, m.co2_ppm >= co2_warning_thr && m.co2_ppm < co2_alarm_thr);
  74         digitalWrite(led_green_pin, m.co2_ppm < co2_warning_thr);
  75
  76         if (m.co2_ppm >= co2_alarm_thr && lastppm < co2_alarm_thr) {
  77                 digitalWrite(buzzer_pin, HIGH);
  78                 delay(100);
  79                 digitalWrite(buzzer_pin, LOW);
  80                 delay(100);
  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         }
  89
  90         if (m.co2_ppm >= co2_warning_thr && lastppm < co2_warning_thr) {
  91                 digitalWrite(buzzer_pin, HIGH);
  92                 delay(500);
  93                 digitalWrite(buzzer_pin, LOW);
  94         }
  95
  96         lcd.setCursor(0, 0);
  97         lcd.print("CO2: ");
  98         lcd.print(m.co2_ppm);
  99         lcd.print(" ppm         ");
 100
 101         lastppm = m.co2_ppm;
 102         delay(5000);
 103 }