#include <MHZ.h>
#include <LiquidCrystal.h>

const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

// pin for pwm reading
#define CO2_IN 10

// pin for uart reading
#define MH_Z19_RX 4  // D7
#define MH_Z19_TX 0  // D6

MHZ co2(MH_Z19_RX, MH_Z19_TX, CO2_IN, MHZ19B);

void setup() {
  Serial.begin(9600);
  pinMode(CO2_IN, INPUT);
  delay(100);
  Serial.println("MHZ 19B");

  lcd.begin(16,1);             // ***** 16 columns, 1 row
  lcd.clear();                 // ***** clear the display, cursor upper left
  lcd.print("hello, world!");  // ***** print something so we know it's working
  delay(5000);                 // ***** allow time to read it before proceeding
              // ***** get rid of the delay() when everything is working *****

  // enable debug to get addition information
  // co2.setDebug(true);

  if (co2.isPreHeating()) {
    Serial.print("Preheating");
    while (co2.isPreHeating()) {
      Serial.print(".");
      delay(5000);
    }
    Serial.println();
  }
}

void loop() {
  Serial.print("\n----- Time from start: ");
  lcd.clear();                  // ***** position the cursor at upper left
  lcd.print(millis() / 1000);
  Serial.println(" s");


  int ppm_pwm = co2.readCO2PWM();
  lcd.print("PPM:");        // ***** these will go right after the " s"
  lcd.print(ppm_pwm);

  Serial.println("\n------------------------------");
  delay(5000);

}