/* J. Paewai 2024 - A battery level indercator for LCD display
This just using the raw ADC value 0-1023 to divide into 5 equal parts
100%, 75%, 25% Under 10% and if under 5V assumes that USB power is being used

Great to add to other projects.
You will need place your own voltage divider and adjust the battery indercation levels 
to suit the battery your are wanting to monitor. 

*/

#include <LiquidCrystal_I2C.h>
#define I2C_ADDR    0x27
#define LCD_COLUMNS 16
#define LCD_LINES   2
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

// Battery Measurement
#define BatCheckTime 1000                 // Check Battery every 1 second
unsigned long BatTime = 0;                // current time of bettery check 
unsigned char Blink_S = 0;                // Battery blink status
#define batteryPin A0                     // Where the voltage divider is located 
  
// Timmers
unsigned long msNow = 0;                  // current processor time

// Create a battery full/empty characters
byte EmptyEnd[] = { B11111, B10000, B10000, B10000, B10000, B10000, B10000, B11111 };
byte EmptyMiddle[] = { B11111, B00000, B00000, B00000, B00000, B00000, B00000, B11111 };
byte EmptyCap[] = { B11110, B00010, B00010, B00001, B00001, B00010, B00010, B11110 }; 
byte FullBody[]  =  { B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111 };
byte FullCap[]  =  { B11110, B11110, B11111, B11111, B11111, B11111, B11110, B11110 };

void getbatt(void)   // Reads analogue which your voltage divider is on and updates the LCD battery graphics
{
 int U = analogRead(batteryPin);
 
 if (U >= 700){           // Battery 100%
   lcd.setCursor(11, 0);  
   lcd.write(byte(3));            
   lcd.write(byte(3));
   lcd.write(byte(3));
   lcd.write(byte(4));  
  }  
  else if (U >= 642){     // Battery 75%
   lcd.setCursor(11, 0);  
   lcd.write(byte(3));           
   lcd.write(byte(3)); 
   lcd.write(byte(3)); 
   lcd.write(byte(2)); 
  }   
  else if (U >= 560){     // Battery 50%
   lcd.setCursor(11, 0);  
   lcd.write(byte(3));             
   lcd.write(byte(3)); 
   lcd.write(byte(1)); 
   lcd.write(byte(2));   
  }
  else if (U >=528){      // Battery 25% 
   lcd.setCursor(11, 0);  
    lcd.write(byte(3));            
    lcd.write(byte(1)); 
    lcd.write(byte(1)); 
    lcd.write(byte(2));  
  }  
  else if (U < 397){       // Less Than 10%
    lcd.setCursor(11, 0);  
    lcd.print ("USBpw"); 
   }
 else { 
   if (Blink_S ==1){        // Flashes the battery indercator for very low capacity
    lcd.setCursor(11, 0);  
    lcd.write(byte(0));              
    lcd.write(byte(1));  
    lcd.write(byte(1));  
    lcd.write(byte(2));  
     Blink_S = 0;  
   }
   else{ 
    if (Blink_S ==0) {
      lcd.setCursor(11, 0);  
      lcd.print("     ");
      Blink_S =1 ;       
    }
   }        
 }
}


void setup() {

  lcd.init();        // init the display
  lcd.backlight();   // Back light on

  // Create the special battery characters
  lcd.createChar(0, EmptyEnd);
  lcd.createChar(1, EmptyMiddle);
  lcd.createChar(2, EmptyCap);
  lcd.createChar(3, FullBody);
  lcd.createChar(4, FullCap);

  pinMode(batteryPin,INPUT); // MCU voltage divider pin to INPUT

}


void loop() {
  msNow=millis();         // get micro time

  if(BatTime < msNow) {   // good place to check the battery - update every second
   getbatt();
   BatTime = millis()+ BatCheckTime;
  }

  // add own project code


// Displays the analogue value on the battery port 
  lcd.setCursor(0,1);
  lcd.print("Value: ");
  lcd.setCursor(7,1);lcd.print(analogRead(batteryPin),DEC);lcd.print("  ");
}