// Wire Bibliothek einbinden
#include <Wire.h>
// für Timings und Interrupts 
#include <TimerOne.h>        
// Vorher hinzugefügte LiquidCrystal_I2C Bibliothek einbinden
#include <LiquidCrystal_I2C.h>
//Hier wird festgelegt um was für einen Display es sich handelt. In diesem Fall eines mit 16 Zeichen in 2 Zeilen und der HEX-Adresse 0x27. 
//Für ein vierzeiliges I2C-LCD verwendet man den Code "LiquidCrystal_I2C lcd(0x27, 20, 4)"  
LiquidCrystal_I2C lcd(0x27, 16, 2); 

// Define Reed contact pin
const int reedPin = 2;

// Define LED pins
const int redLED = 8;
const int yellowLED = 9;
const int greenLED = 10;

// Define potentiometer pins
const int lowerThresholdPot = A0;
const int upperThresholdPot = A1;

// Define thresholds
int lowerThreshold = 0;
int upperThreshold = 0;

// Define current RPM
int currentRPM = 0;

// Previous threshold values for LCD update
int prevLowerThreshold = 0;
int prevUpperThreshold = 0;

unsigned long lastTime = 0;

void setup() {
  Timer1.initialize();
  
  // Initialize serial communication
  Serial.begin(9600);

  pinMode(reedPin, INPUT);
  pinMode(redLED, OUTPUT); // set pin #8 as OUTPUT pin
  pinMode(yellowLED, OUTPUT); // set pin #9 as OUTPUT pin
  pinMode(greenLED, OUTPUT); // set pin #10 as OUTPUT pin

  // Initialize LCD
  lcd.init();
  lcd.backlight(); // Optionally, turn on backlight

  checkThresholds();
  
  // Print initial thresholds to LCD
  updateLcdThreshold(lowerThreshold, upperThreshold);
    
  printSerial("lower", lowerThreshold);
  printSerial("upper", upperThreshold);
}

void loop() {
  // Read Reed contact signal
  int reedSignal = digitalRead(reedPin);

  // Increment RPM counter if Reed contact is closed
  if (reedSignal == HIGH) {
    currentRPM++;
  }

  checkThresholds();  
   
  // Update RPM counter every second
  unsigned long currentTime = millis();

  if (currentTime - lastTime >= 1000) {
    currentRPM = 0;
    lastTime = currentTime;  
  }   

  // Update LCD display with thresholds
  if (lowerThreshold != prevLowerThreshold || upperThreshold != prevUpperThreshold) {
    // Print actual thresholds to LCD
    updateLcdThreshold(lowerThreshold, upperThreshold);

    prevLowerThreshold = lowerThreshold;
    prevUpperThreshold = upperThreshold;
  } 

  // Update LCD display with current RPM
  updateLcdRpm(currentRPM);

  // Check thresholds and update LEDs
  if (currentRPM < lowerThreshold) {
    redLedOn();  
  } else if (currentRPM < upperThreshold) {
    yellowLedOn();
  } else {
    greenLedOn();
  }

  // Delay
  delay(50);
}

void updateLcdThreshold( int lowerThreshold, int upperThreshold){
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("U:");
  lcd.print(lowerThreshold);
  lcd.setCursor(8, 0);
  lcd.print(" O:");
  lcd.print(upperThreshold);
}

void updateLcdRpm( int currentRPM){
  lcd.setCursor(0, 1);
  lcd.print("RPM:");
  lcd.print(currentRPM);
}

void printSerial( String valueName, int value){
  Serial.print(valueName + " :");
  Serial.println(value);
}

void checkThresholds(){
  // Map potentiometer values to thresholds
  lowerThreshold = map(analogRead(lowerThresholdPot), 0, 1023, 0, 6000);
  upperThreshold = map(analogRead(upperThresholdPot), 0, 1023, 0, 6000);
}

void redLedOn(){
  digitalWrite(redLED, HIGH);
  digitalWrite(yellowLED, LOW);
  digitalWrite(greenLED, LOW);
}

void yellowLedOn(){
  digitalWrite(redLED, LOW);
  digitalWrite(yellowLED, HIGH);
  digitalWrite(greenLED, LOW);
}

void greenLedOn(){
  digitalWrite(redLED, LOW);
  digitalWrite(yellowLED, LOW);
  digitalWrite(greenLED, HIGH);
}