#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

const float GAMMA = 0.7;
const float RL10 = 50;
const int LDR_PIN = A1;

float readLDR() {
  int analogValue = analogRead(LDR_PIN);
  float voltage = analogValue / 1024.0 * 5.0;
  float resistance = 2000.0 * voltage / (5.0 - voltage); 
  return pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, 1.0 / GAMMA);
}

const float BETA = 3950;
int analogValue;
float celsius;

void setup() {
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  Serial.begin(9600);
  lcd.init();  
  lcd.backlight(); 
}

void loop() {
  int sel = analogRead(A5); 
  sel = map(sel, 0, 1023, 0, 7);
  Serial.println(sel);
  switch (sel) {
    case 0:
      ch0();
      break;
    case 1:
      ch1();
      break;
    case 2:
      ch2();
      break;
    case 3:
      ch3();
      break;
    case 4:
      ch4();
      break;
    case 5:
      temp1();
      break;
    case 6:
      temp2();
      break;
    case 7:
      lightSensor();
      break;
  }
}

void ch0() {
  lcd.setCursor(2, 0);
 lcd.print("Channel 0=");
  lcd.setCursor(2, 1);
  lcd.print(analogRead(A0));  
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
}
void ch1() {
  lcd.setCursor(2,0);
 lcd.print("Channel 1=");
 lcd.setCursor(2,1);
 lcd.print(analogRead(A0));
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);
  digitalWrite(6, HIGH);
  digitalWrite(7, LOW);
}

void ch2() {
  lcd.setCursor(2,0);
 lcd.print("Channel 2=");
 lcd.setCursor(2,1);
 lcd.print(analogRead(A0));
  digitalWrite(4, LOW);
  digitalWrite(5, HIGH);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
}

void ch3() {
  lcd.setCursor(2,0);
 lcd.print("Channel 3=");
 lcd.setCursor(2,1);
 lcd.print(analogRead(A0));
  digitalWrite(4, LOW);
  digitalWrite(5, HIGH);
  digitalWrite(6, HIGH);
  digitalWrite(7, LOW);
}

void ch4() {
  lcd.setCursor(2,0);
 lcd.print("Channel 4=");
 lcd.setCursor(2,1);
 lcd.print(analogRead(A0));
  digitalWrite(4, HIGH);
  digitalWrite(5, LOW);
  digitalWrite(6, HIGH);
  digitalWrite(7, HIGH);
}

void temp1() {  lcd.setCursor(1,0);
  lcd.print("tem 1=");
  analogValue = analogRead(A0);
  celsius = 1.0 / (log(1.0 / (1023.0 / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  lcd.setCursor(1,1);
  lcd.print(celsius);
   lcd.print(" Celsius");
  digitalWrite(4, HIGH);
  digitalWrite(5, HIGH);
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
}

void temp2() {
  lcd.setCursor(1,0);
  lcd.print("tem 2=");
  analogValue = analogRead(A0);
  celsius = 1.0 / (log(1.0 / (1023.0 / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  lcd.setCursor(1,1);
  lcd.print(celsius);
   lcd.print(" Celsius");
  digitalWrite(4, HIGH);
  digitalWrite(5, HIGH);
  digitalWrite(6, HIGH);
  digitalWrite(7, LOW);
}

void lightSensor() {
  lcd.setCursor(0,0);
 lcd.println("Light Sensor=");
  float luxValue = readLDR(); 
  lcd.setCursor(0,1);
 lcd.print(luxValue);
  lcd.print(" luxvalue ");
  digitalWrite(4, HIGH);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, HIGH);
}