#include <Wire.h>

float calibration_value = 21.34 + 3;
int phval = 0; 
unsigned long int avgval; 
int buffer_arr[10],temp;
float pH_act;
byte string_received = 0;            

const int Pump_1 = 2;  // the Arduino pin, which connects to the pin of relay
const int Pump_2 = 3;  // the Arduino pin, which connects to the pin of relay

void setup() {
	Wire.begin();
	Serial.begin(9600);
	pinMode(Pump_1, OUTPUT); 
	pinMode(Pump_2, OUTPUT); 
}

void loop() {
	// put your main code here, to run repeatedly:
	for(int i=0;i<10;i++) 
	{ 
		buffer_arr[i]=analogRead(A0);
		delay(30);
	}
	for(int i=0;i<9;i++)
	{
		for(int j=i+1;j<10;j++)
		{
			if(buffer_arr[i]>buffer_arr[j])
			{
				temp=buffer_arr[i];
				buffer_arr[i]=buffer_arr[j];
				buffer_arr[j]=temp;
			}
		}
	}
	avgval=0;
	for(int i=2;i<8;i++)
	{
		avgval+=buffer_arr[i];
	}
	float volt=(float)avgval*5.0/1024/6; 
	pH_act = -5.70 * volt + calibration_value;

	Serial.println("pH Val: ");
	Serial.print(pH_act);
	delay(1000);
 
	if (pH_act < 6.5) {		//test condition against pH reading
    	Serial.println("PH LEVEL LOW,Pump_1 = ON");
    	digitalWrite(Pump_1, HIGH);
 		delay(3000);
    	//if condition is true, send command to turn on pump (called PMP_UP) and dispense pH up solution, in amounts of 0.5ml. Pump turns clockwise.
    }
    else {
      	digitalWrite(Pump_1, LOW);		//if condition is false, send command to turn off pump (called PMP_UP)
    }
  
    if (pH_act > 7.5) {		//test condition against pH reading
      	Serial.println("PH LEVEL HIGH,Pump_2 = ON");
      	digitalWrite(Pump_2, HIGH);
      	delay(3000);		//if condition is true, send command to turn on pump (called PMP_DOWN) and dispense pH down solution, in amounts of 0.5ml. Pump turns counter-clockwise.
    }
    else {
     	digitalWrite(Pump_2, LOW);		//if condition is false, send command to turn off pump (called PMP_DOWN)
    }
  	Serial.println();
}