/*
 
 This sketch reads user input from the keyboard and sends data
 to the selected COM port so as to control the RC car.
  
 Version 1.0
 Code licensed under Creative Commons Attribution-ShareAlike 3.0 License
 https://creativecommons.org/licenses/by-sa/3.0/
  
 by John Tompros (2009)
 
 https://sites.google.com/site/electronicprojectsprogramming
  
 Motor for forward and reverse is connected to channel 0
 Motor for left and right is connected to channel 1  
  
 */
 
import processing.serial.*;  //Required library
 
Serial comPort;           //Create a serial port object
int speedForward = 0;     //Integer to hold the forward speed rate. Set initial forward speed rate
int speedReverse = 0;     //Integer to hold the reverse speed rate. Set initial reverse speed rate
 
void setup()  //Runs once
{
  size(400, 400); //Just for showing the window
  background(0);  //Set background color
 
  println(Serial.list());  //Notice how your com port is listed
 
  //Select serial port for communication. You must change the number inside [] to correspond to your correct com port of your pc
  //in my case, com port 4 is assigned the number 1
  comPort = new Serial(this, Serial.list()[1], 9600);
}
 
void draw() {                        //This is the main loop
  if(keyPressed == true) {           //Checks to see if a keyboard key has been pressed. Returns true if a key has been pressed
    if (key == 'e' || key == 'E') {  //Set forward key
      delay(10);
      speedForward ++;    //Increase forward speed as long as the key is pressed
      comPort.write(136); //Send command to the motor controller to start the motor (in forward) connected to channel 0
                          //This information is found in the datasheet of the motor controller   
      comPort.write(speedForward); //Send current motor speed
      //println(speedForward);      
    }
    else if (key == 'c' || key == 'C'){  //Set key to reduce speed and to stop the motor eventually
      if(speedForward <= 5){  //Minimum motor speed threshold, to avoid negative numbers to be passed as commands to the motor controller
        comPort.write(134);   //Send command to the motor controller to stop the motor connected to channel 0   
        comPort.write(60);    //Apply partial brakes
        delay(300);           
        comPort.write(134);   //Send command to the motor controller to stop the motor connected to channel 0   
        comPort.write(127);   //Apply full brakes
        speedForward = 0;     //Reset forward speed
        speedReverse = 0;     //Reset reverse speed
      }
      else{
        speedForward --;              //Else reduce forward speed
        comPort.write(136);           //Send command to the motor controller to apply current speed to the motor connected to channel 0
        comPort.write(speedForward);  //Send current reduced motor speed
        //println(speedForward);
      }
    }
    else if(key == 'x' || key == 'X'){  //This key is assigned to the brakes    
      comPort.write(134);               //Send command to the motor controller to stop the motor connected to channel 0   
      comPort.write(60);                //Apply partial brakes
      delay(300);
      comPort.write(134);               //Send command to the motor controller to stop the motor connected to channel 0   
      comPort.write(127);               //Apply full brakes
      speedForward = 0;                 //Reset forward speed
      speedReverse = 0;                 //Reset reverse speed
    }
    else if(key == 'q' || key == 'Q'){  //This key is assigned to reverse
      delay(10);
      speedReverse ++;                  //Increase reverse speed as long as the key is pressed
      comPort.write(138);               //Send command to the motor controller to start the motor (in reverse) connected to channel 0   
      comPort.write(speedReverse);      //Send current reverse motor speed
      speedForward = 0;                 //Reset forward speed
    }
    else if(key == CODED){
      if(keyCode == LEFT){   //Set key for left steering
 
        //Send command to the motor controller to start the motor (in forward) connected to channel 1
        //that is the channel where the motor responsible for the steering is connected to
        comPort.write(140);
 
        //Send a value to start the steering motor
        comPort.write(45);
      }
      else if(keyCode == RIGHT){  //Set key for right steering
 
        //Send command to the motor controller to start the motor (in reverse) connected to channel 1
        //that is the channel where the motor responsible for the steering is connected to
        comPort.write(142);      
 
        //Send a value to start the steering motor in the opposite direction
        comPort.write(45);
      }
      else if(keyCode == UP || keyCode == DOWN){  //Set keys for returning the steering to the center
        comPort.write(135);                       //Send command to the motor controller to stop the steering motor
        comPort.write(0);                         //Send the stop value
      }
    }
  }
  if(speedForward >= 110){  //Set a speed limit
    comPort.write(134);     //Send command to the motor controller to stop the motor connected to channel 0   
    comPort.write(60);      //Apply partial brakes
    delay(300);
    comPort.write(134);     //Send command to the motor controller to stop the motor connected to channel 0   
    comPort.write(127);     //Apply full brakes
    speedForward = 0;       //Reset forward speed
    speedReverse = 0;       //Reset reverse speed
  }  
}

comPort = new Serial(this, Serial.list()[1], 9600);