/*
 * 
 * Arduino Sketch for Allegro ACS712 Current Sensor with LCD1602/LCD2004 with I2C 
 * This sensor can measure current at a range of up to 30A.
 * The current is measured and displayed on LCD1602 or LCD2004.
 * The current is also displayed on the Serial monitor (click Tools->Serial monitor).
 * It operates with 5V.
 * Please watch the video instruction and explanation for this code.
 * 
 * Written by Ahmad Shamshiri on July 14, 2018 at 07:02 in Ajax, Ontario, Canada
 * for Robojax.com
 * View the video instruction at https://youtu.be/kzXouSzvcp8
 * This code has been downloaded from Robojax.com
 
  * You must watch the following two videos before you can understand this:
 * 1- Introduction to ACS712 Current Sensor: https://www.youtube.com/watch?v=DVp9k3xu9IQ
 * 2- LCD1602 with I2C display: https://www.youtube.com/watch?v=q9YC_GVHy5A
 */
#define VIN A0 // define the Arduino pin A0 as voltage input (V in)
const float VCC   = 5.0;// supply voltage is from 4.5 to 5.5V. Normally 5V.
const int model = 2;   // enter the model number (see below)

float cutOffLimit = 1.01;// set the current which, below that value, doesn't matter. Or set 0.5

/*
          "ACS712ELCTR-05B-T",// for model use 0
          "ACS712ELCTR-20A-T",// for model use 1
          "ACS712ELCTR-30A-T"// for model use 2  
Sensitivity array is holding the sensitivity of the ACS712
current sensors. Do not change. All values are from page 5 of the data sheet          
*/
float sensitivity[] ={
          0.185,// for ACS712ELCTR-05B-T
          0.100,// for ACS712ELCTR-20A-T
          0.066// for ACS712ELCTR-30A-T
     
         }; 


const float QOV =   0.5 * VCC;// set quiescent Output voltage of 0.5V
float voltage;// internal variable for voltage


// start of settings for LCD1602 with I2C
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x27, 16, 2);
// end of settings for LCD1602 with I2C

void setup() {
    //Robojax.com ACS712 Current Sensor 
    Serial.begin(9600);// initialize serial monitor
    Serial.println("Robojax Tutorial");
    Serial.println("ACS712 Current Sensor");
  // initialize the LCD
  lcd.begin();  
  lcd.backlight();
  lcd.print("Robojax ACS712");
  lcd.setCursor(0,1);
  lcd.print("Demo"); 
  delay(2000);     
}

void loop() {
  

  //Robojax.com ACS712 Current Sensor with LCD1601
  float voltage_raw =   (5.0 / 1023.0)* analogRead(VIN);// Read the voltage from sensor
  voltage =  voltage_raw - QOV + 0.012 ;// 0.000 is a value to make voltage zero when there is no current
  float current = voltage / sensitivity[model];
 
  if(abs(current) > cutOffLimit ){
    Serial.print("V: ");
    Serial.print(voltage,3);// print voltage with 3 decimal places
    Serial.print("V, I: ");
    Serial.print(current,2); // print the current with 2 decimal places
    Serial.println("A");
    //start of loop Robojax code ACS712 with LCD1602 and I2C
    lcd.clear();
    lcd.setCursor (0,0); // set to line 1, char 0  
    lcd.print("Robojax ACS712");
    lcd.setCursor (0,1); // set to line 1, char 0  
    lcd.print("Current: ");
    lcd.setCursor (9,1); // go to start of 2nd line
    lcd.print(current);
    lcd.setCursor (14,1); // go to start of 2nd line
    lcd.print("A");
 
  }else{
    Serial.println("No Current");
    lcd.clear();
    lcd.setCursor (0,0); // set to line 1, char 0 
    lcd.print("No Current");     
  }
  delay(500);
}