+ Serial.begin(115200);
+ Serial.println("Time,CO2,Temp");
+
+ // MH-Z19
+ mhz19.begin(rx_pin, tx_pin);
+
+ // LCD
+ lcd.begin(16, 2);
+ lcd.setCursor(0, 0);
+ lcd.print("Airing Butler");
+ lcd.setCursor(0, 1);
+ lcd.print("says hello!");
+
+ // LEDs
+ pinMode(led_green_pin, OUTPUT);
+ pinMode(led_yellow_pin, OUTPUT);
+ pinMode(led_red_pin, OUTPUT);
+ digitalWrite(led_green_pin, HIGH);
+ delay(500);
+ digitalWrite(led_green_pin, LOW);
+ digitalWrite(led_yellow_pin, HIGH);
+ delay(500);
+ digitalWrite(led_yellow_pin, LOW);
+ digitalWrite(led_red_pin, HIGH);
+ delay(500);
+ digitalWrite(led_red_pin, LOW);
+
+ // buzzer
+ pinMode(buzzer_pin, OUTPUT);
+ buzz(200, 1);
+
+ lcd.clear();