int speedPinM1A = 3;      // PWM pin for speed control
int directionPinM1B = 9; // PWM pin for direction control
int speedPinM2A = 10;      // PWM pin for speed control
int directionPinM2B = 11; // PWM pin for direction control
int userInput;
int vpInputSpeed;
int dcMotorSpeed;

void serialFlush(){
  while(Serial.available() > 0) {
    char t = Serial.read();
  }
}

void setup() {
  Serial.begin(9600);
  pinMode(speedPinM1A, OUTPUT);
  pinMode(directionPinM1B, OUTPUT);
  pinMode(speedPinM2A, OUTPUT);
  pinMode(directionPinM2B, OUTPUT);
}

void loop(){
  Serial.print("Choose any one option: ");
  Serial.println("1. Run vacuum pump only ");
  Serial.println("2. Run DC motor only ");
  Serial.println("3. Both");
  Serial.println("Write 1,2,3 to select any one of these according to your need/choice");
  serialFlush();
  while (Serial.available()<1){}
  if (Serial.available() > 0)  // reply only when you receive data:
  {
    Serial.print("Loop Serial Available: ");
    Serial.println(Serial.available());
    userInput=Serial.parseInt();  //Reading the data from serial and storing the data
    serialFlush();
    Serial.print("User Input: ");
    Serial.println(userInput);

    switch(userInput)
    {  
      case 1:
      runvacuumpump();     
      break;  
        
      case 2:  
      rundcmotor();
      break; 
        
      case 3:  
      runvacuumpump();
      rundcmotor();
      break;

      default:
      Serial.print("Please enter a valid selection");

    }
  }

}

void runvacuumpump()
{
  Serial.println("Choose any one");
  Serial.println("1. Run");
  Serial.println("2. Stop");
  Serial.println("Write R or S according to your need");

  while (Serial.available()<1){}

  if(Serial.available() > 0){
    Serial.print("Vacuum pump Serial Available: ");
    Serial.println(Serial.available());

    char vpCommand = Serial.read();
    Serial.print("Vacuum pump command -");
    Serial.println(vpCommand);
    serialFlush();

    if (vpCommand=='R')
    {
      Serial.println("Enter Speed for vacuum Pump within the range of 1 to 255");
      serialFlush();
      while (Serial.available ()<1){}

      if (Serial.available() > 0)
      {
        vpInputSpeed = Serial.parseInt();
        Serial.print("Vacuum Pump input speed-");
        Serial.println(vpInputSpeed);
        serialFlush();

        if(vpInputSpeed > 0 && vpInputSpeed <=255)
        {
          analogWrite(speedPinM2A, vpInputSpeed);
          digitalWrite(directionPinM2B, LOW);
          Serial.println("Vacuum Pump is Running..");
        }
        else{
          Serial.println("Please enter value between 1 to 255..");
          runvacuumpump();
        }
      }
    }
    else if(vpCommand=='S'){
       analogWrite(speedPinM2A, 0);
       digitalWrite(directionPinM2B,LOW);
       Serial.println("Vacuum Pump STOPPED");
  }

  else{
    Serial.println("Please enter valid Input");
    runvacuumpump();
  }
}
}

void rundcmotor(){
  Serial.print("Choose any one option: ");
  Serial.println("1. FORWARD ");
  Serial.println("2. BACKWARD ");
  Serial.println("3. STOP");
  Serial.println("WRITE F for Forward, Write B for Backward and Write S to stop the Motor");
  while (Serial.available()<1){}
   
  if (Serial.available() > 0) {
      Serial.print(" Vacuum pump Serial Available: ");
      Serial.println(Serial.available());
    char command = Serial.read();
    Serial.print("Command-");
    Serial.println(command);
    serialFlush();
    

    if (command == 'B'){
      //Serial.println("RUN");
      Serial.println("Enter the value for speed within the range of 0 to 255 ");
      serialFlush();
      while (Serial.available()<1){}

      if (Serial.available() > 0){
        dcMotorSpeed=255-Serial.parseInt();  //Reading the data from serial and storing the data
        Serial.print("DC Motor Input SPEED: ");
        Serial.println(dcMotorSpeed);
        serialFlush();
        if (dcMotorSpeed >= 0 && dcMotorSpeed <255){
          analogWrite(speedPinM1A, dcMotorSpeed);
          digitalWrite(directionPinM1B, HIGH); // Seting direction for Backward
          Serial.println("MOTOR IS RUNNING IN BACKWARD DIRECTION");  
        }
      }

    } 

    else if(command == 'F'){
     // Serial.println("RUN1");
      Serial.println("Enter the value for speed within the range of 0 to 255 ");
      serialFlush();
      while (Serial.available ()<1){}

      if (Serial.available() > 0){
        dcMotorSpeed=Serial.parseInt();  //Reading the data from serial and storing the data
        serialFlush();
        Serial.println("User Input SPEED: ");
        Serial.println(dcMotorSpeed);

        if(dcMotorSpeed > 0 && dcMotorSpeed <=255){
          analogWrite(speedPinM1A, dcMotorSpeed);
          digitalWrite(directionPinM1B, LOW); // Set direction for Forward
          Serial.println("MOTOR IS RUNNING IN FORWARD DIRECTION");
        }
      }
    }

    else if(command == 'S'){  
      analogWrite(speedPinM1A, 0);
      digitalWrite(directionPinM1B,LOW);
      Serial.println("DC Motor Stopped");
    }

    else{
      Serial.println("Please enter valid Input");
      rundcmotor();
    }
  }
}