/*
   Forum: https://forum.arduino.cc/t/im-trying-to-make-an-automatic-watering-system-with-a-1602-i2c-lcd-a-relay-for-toggling-the-pump-and-a-capacitive-soil-moisture-sensor/1442240
   Wokwi: https://wokwi.com/projects/462850559170269185

  TO sketch with modifications

  2026/05/01
  ec2021

*/

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int soilMoisturePin = A0;
const int BUTTON_PIN = 3;
const int RELAY_PIN  = 7;

int sensorValue = 0;
int moisturePercent = 0;
constexpr unsigned long interval = 200; // Measure the moisture every 200 ms
unsigned long lastMeasurement = 0;
byte btnDown;

void setup()
{
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Zemlja ");
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(RELAY_PIN, OUTPUT);
}

void loop()
{
  if (millis() - lastMeasurement >= interval) {
    lastMeasurement = millis();
    sensorValue = analogRead(soilMoisturePin);
    sensorValue = constrain(sensorValue, 0, 1020);
    moisturePercent = map(sensorValue, 0, 1020, 100, 0);
    lcd.setCursor(0, 0);
    lcd.print(moisturePercent);
    lcd.print(" %   ");
  }
  btnDown = !digitalRead(BUTTON_PIN);
  if (moisturePercent < 40 || btnDown) {
    WateringInProgress();
  }
}

void WateringInProgress() {
  if (btnDown) {
    lcdPrint("Manual override");
  } else {
    lcdPrint("Watering       ");
  }
  digitalWrite(RELAY_PIN, HIGH);
  delay(3800);
  digitalWrite(RELAY_PIN, LOW);
  lcdPrint("Not watering    ");
}

void lcdPrint(char* msg) {
  lcd.setCursor(0, 1);
  lcd.print(msg);
}