/*
Digitale relative vochtigheids en thermometer met max en min meting.

Resetten van max en min door een reset van het boord.

Rob Kalmeijer.
*/

#include <DHT.h>
#include <LiquidCrystal.h>

#define btnRIGHT 0
#define btnUP 1
#define btnDOWN 2
#define btnLEFT 3
#define btnSELECT 4
#define btnNONE 5
#define btnUNKNOWN 6

#define DHTTYPE  DHT11     // DHT 11
#define DHTPIN   22        // Pin connected to the DHT sensor.

int readkeypad(){
  int adc_key_in = analogRead(0);
  int ret = btnUNKNOWN;

  if (adc_key_in < 50) ret = btnRIGHT;
  if ((adc_key_in > 120) && (adc_key_in < 150)) ret = btnUP;
  if ((adc_key_in > 250) && (adc_key_in < 350)) ret = btnDOWN;
  if ((adc_key_in > 450) && (adc_key_in < 500)) ret = btnLEFT;
  if ((adc_key_in > 700) && (adc_key_in < 750)) ret = btnSELECT;
  if ((adc_key_in > 850) && (adc_key_in < 1150)) ret = btnNONE;
  
  return ret;
}

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

float hMax=0, hMin=100;
float tMax=-40, tMin=100;

void setup() {
  lcd.begin(16, 2);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Termometer en");
  lcd.setCursor(0,1);
  lcd.print("Hygrometer");
  dht.begin();
  delay(3000);
  lcd.clear();
}

void loop() {
  //Reset de Max en Min waardes van T en H
  float h, t;

  unsigned long rtime, lasttime;

  rtime=millis();

  if ((rtime - lasttime) > 2000) {
      // Reading temperature or humidity takes about 250 milliseconds!
      // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
      h = dht.readHumidity();
      // Read temperature as Celsius (the default)
      t = dht.readTemperature();
      lasttime = rtime;
  }

  if (t > tMax) {
    tMax=t;
  }

  if (t < tMin) {
    tMin=t;
  }

  if (h > hMax) {
    hMax=h;
  }

  if (h < hMin) {
    hMin=h;
  }

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t)) {
    lcd.setCursor(0,0);
    lcd.print("Error:          ");
    lcd.setCursor(0,1);
    lcd.print("No DHT sensor   ");
    return;
  }

  switch(readkeypad()) {
    case 0:
      lcd.setCursor(0,0);
      lcd.print("Hmax: ");
      lcd.print(hMax);
      lcd.print(" %     ");
      lcd.setCursor(0,1);
      lcd.print("Hmin: ");
      lcd.print(hMin);
      lcd.print(" %     ");
      break;
    case 3:
      lcd.setCursor(0,0);
      lcd.print("Tmax: ");
      lcd.print(tMax);
      lcd.print(" C     ");
      lcd.setCursor(0,1);
      lcd.print("Tmin: ");
      lcd.print(tMin);
      lcd.print(" C     ");
      break;
    default:
      lcd.setCursor(0, 0);
      lcd.print("T: ");
      lcd.print(t);
      lcd.print(" C     ");
      lcd.setCursor(0, 1);
      lcd.print("H: ");
      lcd.print(h);
      lcd.print(" %     ");
      break;
  }
}