Modify servo_serial.pde so that it monitors a kill switch: - If the Kill switch

Question

Modify servo_serial.pde so that it monitors a kill switch:
- If the Kill switch (P3 pushbutton) is pressed, the program should enter the Stop state.
- If the Start switch (P4 pushbutton) is pressed, the program should enter the Start state.
- In the Stop state, the Serial should not accept any commands. It should display: “Press Start switch to start servo”.
- In the Start state, the program should function normally.
- If power is disconnected and reconnected, the program should enter the Stop State.
- Hint: Think about adding a variable to keep track of your start and stop states.
- Hint: Use debug to see what your variables are seeing, and the ADI scope to see your voltages.

Here is the code for servo_serial:

Explanation / Answer

The explanation to the changes in the code is explained in the comments to the commands as below-

#include <Servo.h>
Servo myservo; //create servo object to control a servo
int pos = 0; //variable to store the servo position
int myDirection;
int start = 0; //start variable to check if Start button is pressed
int stop = 0; //stop variable to check if Stop button is pressed

void setup()
{
   myservo.attach(9);
   Serial.begin(9600);
   start = 0; //making sure that when system is restarted, it enters stop state
   stop = 0; //making sure that when system is restarted, it enters stop state
   Serial.println("Enter Direction (L or R):"); //prompt the user
   pinMode(13, INPUT); //Define Pin 13 for taking input for Start Button
   pinMode(14, INPUT); //Define Pin 14 for taking input for Stop Button
}

void loop()
{  
   start = digitalRead(13); //Read value from start button
   stop = digitalRead(14); //Read value from stop button
   if((start == HIGH) && (stop == LOW)) //Check whether only the start button is pressed. In any other case, it goes to the else condition.
   {
       if(Serial.available()) //check for input
       {
           myDirection = Serial.read(); //read the input
       }
       if(myDirection == 'L') //go left
      
       {
           if(pos < 180)
           {
               pos += 1;
           }
       }
       else if(myDirection = 'R') //go right
       {
           if(pos > 0)
           {
               pos -= 1;
           }
       }
       myservo.write(pos);
       delay(15);
   }
   else
   {
       Serial.write("Press Start switch to start servo"); //Print if stop button is pressed or any other undesired case.
   }
}

If required, you can change the input pins for the start and stop buttons.

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