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Help with combining line following and remote codes for Zumo


#1

Hey gang,
We are a budding high school Zumo team and need some help getting started. We are trying to combine the line following and rc code functions into 1 code. The functionality of this hybrid code would be as follows:

  1. Push the Zumo button once and the sensor array initiates (it already does this in the line follow code example).
  2. Push the Zumo button a second time and the line following sequence starts (it already does this in the line follow code example).
  3. After executing the line follow code for however long we want it to, pick up the moving Zumo and press the Zumo button a third time. Upon the third button push initiate the RC code.

Does anybody have an idea on how to do this or could anyone offer us a push in the right direction? Any help will be appreciated. Our code efforts so far look like this:

#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#include <ZumoMotors.h>
#include <ZumoBuzzer.h>
#include <Pushbutton.h>
#include <ZumoMotors.h>

#define THROTTLE_PIN   4 // throttle channel from RC receiver
#define STEERING_PIN   5 // steering channel from RC receiver
#define LED_PIN       13 // user LED pin

#define MAX_SPEED             400 // max motor speed
#define PULSE_WIDTH_DEADBAND   25 // pulse width difference from 1500 us (microseconds) to ignore (to compensate for control centering offset)
#define PULSE_WIDTH_RANGE     350 // pulse width difference from 1500 us to be treated as full scale input (for example, a value of 350 means
                                  //   any pulse width <= 1150 us or >= 1850 us is considered full scale)


ZumoBuzzer buzzer;
ZumoReflectanceSensorArray reflectanceSensors;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON);
int lastError = 0;

// This is the maximum speed the motors will be allowed to turn.
// (400 lets the motors go at top speed; decrease to impose a speed limit)
const int MAX_SPEED = 400;


void setup()
{
  // Play a little welcome song
  buzzer.play(">g32>>c32");

  // Initialize the reflectance sensors module
  reflectanceSensors.init();

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Turn on LED to indicate we are in calibration mode
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);

  // Wait 1 second and then begin automatic sensor calibration
  // by rotating in place to sweep the sensors over the line
  delay(1000);
  int i;
  for(i = 0; i < 80; i++)
  {
    if ((i > 10 && i <= 30) || (i > 50 && i <= 70))
      motors.setSpeeds(-200, 200);
    else
      motors.setSpeeds(200, -200);
    reflectanceSensors.calibrate();

    // Since our counter runs to 80, the total delay will be
    // 80*20 = 1600 ms.
    delay(20);
  }
  motors.setSpeeds(0,0);

  // Turn off LED to indicate we are through with calibration
  digitalWrite(13, LOW);
  buzzer.play(">g32>>c32");

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Play music and wait for it to finish before we start driving.
  buzzer.play("L16 cdegreg4");
  while(buzzer.isPlaying());

   pinMode(LED_PIN, OUTPUT);

  // uncomment one or both of the following lines if your motors' directions need to be flipped
  //motors.flipLeftMotor(true);
  //motors.flipRightMotor(true);
}

void loop()
{
 if (ZUMO_BUTTON = 1);
 {
  int throttle = pulseIn(THROTTLE_PIN, HIGH);
  int steering = pulseIn(STEERING_PIN, HIGH);

  int left_speed, right_speed;

  if (throttle > 0 && steering > 0)
  {
    // both RC signals are good; turn on LED
    digitalWrite(LED_PIN, HIGH);

    // RC signals encode information in pulse width centered on 1500 us (microseconds); subtract 1500 to get a value centered on 0
    throttle -= 1500;
    steering -= 1500;

    // apply deadband
    if (abs(throttle) <= PULSE_WIDTH_DEADBAND)
      throttle = 0;
    if (abs(steering) <= PULSE_WIDTH_DEADBAND)
      steering = 0;

    // mix throttle and steering inputs to obtain left & right motor speeds
    left_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) - ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);
    right_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) + ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);

    // cap speeds to max
    left_speed = min(max(left_speed, -MAX_SPEED), MAX_SPEED);
    right_speed = min(max(right_speed, -MAX_SPEED), MAX_SPEED);
  }
  else
  {
    // at least one RC signal is not good; turn off LED and stop motors
    digitalWrite(LED_PIN, LOW);

    left_speed = 0;
    right_speed = 0;
  }

  ZumoMotors::setSpeeds(left_speed, right_speed);
}

if (ZUMO_BUTTON = 0)
  {unsigned int sensors[6];

  // Get the position of the line.  Note that we *must* provide the "sensors"
  // argument to readLine() here, even though we are not interested in the
  // individual sensor readings
  int position = reflectanceSensors.readLine(sensors);

  // Our "error" is how far we are away from the center of the line, which
  // corresponds to position 2500.
  int error = position - 2500;

  // Get motor speed difference using proportional and derivative PID terms
  // (the integral term is generally not very useful for line following).
  // Here we are using a proportional constant of 1/4 and a derivative
  // constant of 6, which should work decently for many Zumo motor choices.
  // You probably want to use trial and error to tune these constants for
  // your particular Zumo and line course.
  int speedDifference = error / 4 + 6 * (error - lastError);

  lastError = error;

  // Get individual motor speeds.  The sign of speedDifference
  // determines if the robot turns left or right.
  int m1Speed = MAX_SPEED + speedDifference;
  int m2Speed = MAX_SPEED - speedDifference;

  // Here we constrain our motor speeds to be between 0 and MAX_SPEED.
  // Generally speaking, one motor will always be turning at MAX_SPEED
  // and the other will be at MAX_SPEED-|speedDifference| if that is positive,
  // else it will be stationary.  For some applications, you might want to
  // allow the motor speed to go negative so that it can spin in reverse.
  if (m1Speed < 0)
    m1Speed = 0;
  if (m2Speed < 0)
    m2Speed = 0;
  if (m1Speed > MAX_SPEED)
    m1Speed = MAX_SPEED;
  if (m2Speed > MAX_SPEED)
    m2Speed = MAX_SPEED;

  motors.setSpeeds(m1Speed, m2Speed);
}

Zumo robot line follow and rc co0mbined code
#2

Hello.

I added code tags to your code to make it easier to read. Please format your code in future posts by putting a backtick (`) before and after the code or indenting the code by four spaces.

I noticed a few errors in your code:

  1. You declared an integer constant MAX_SPEED, which conflicts with the preprocessor constant defined a few lines above. I suggest removing the #define MAX_SPEED 400 line.

  2. In loop(), it looks like you are mistaking the assignment operator (=) for the equality comparison operator (==) in both conditional statements (IF (ZUMO_BUTTON = 1) and IF (ZUMO_BUTTON = 0)). Essentially, you are trying to assign ZUMO_BUTTON to 1 or 0, which you cannot because it is a preprocessor constant defined as (pin) 12 in the Pushbutton class.

One way to get your Zumo Robot for Arduino to execute your RC portion of the code is to call the Pushbutton class method, isPressed(). That function returns true if the Zumo’s user button is pressed. You could use that to set a boolean flag, indicating that the user button has been pressed a third time and initiating your RC code. For example:

bool thirdButtonPress_flag = false;
void loop()
{
   if (thirdButtonPress_flag == false)
   {
      // Run line following code.
      thirdButtonPress_flag = button.isPressed();
   }
   else
   {
      // Run RC code.
   }
}

- Amanda


#3

Hi,

So we tried using the if and else statement, but there is an issue with the else statement when we tried it and we don’t understand what the error is. Can anyone help us figure out what the error is and how to fix it? Below is the code.

#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#include <ZumoMotors.h>
#include <ZumoBuzzer.h>
#include <Pushbutton.h>

#define LED_PIN       13 // user LED pin
#define PULSE_WIDTH_DEADBAND   25 // pulse width difference from 1500 us (microseconds) to ignore (to compensate for control centering offset)
#define PULSE_WIDTH_RANGE     350 // pulse width difference from 1500 us to be treated as full scale input (for example, a value of 350 means
                                  //   any pulse width <= 1150 us or >= 1850 us is considered full scale)


ZumoBuzzer buzzer;
ZumoReflectanceSensorArray reflectanceSensors;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON);
int lastError = 0;

// This is the maximum speed the motors will be allowed to turn.
// (400 lets the motors go at top speed; decrease to impose a speed limit)
const int MAX_SPEED = 400;

void setup()
{
  pinMode(LED_PIN, OUTPUT);

  // uncomment one or both of the following lines if your motors' directions need to be flipped
  //motors.flipLeftMotor(true);
  //motors.flipRightMotor(true);
}

bool thirdButtonPress_flag = false;
void loop()
{
   if (thirdButtonPress_flag == false)
   {
      // Run line following code.
      thirdButtonPress_flag = button.isPressed();
       // Play a little welcome song
  buzzer.play(">g32>>c32");

  // Initialize the reflectance sensors module
  reflectanceSensors.init();

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Turn on LED to indicate we are in calibration mode
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);

  // Wait 1 second and then begin automatic sensor calibration
  // by rotating in place to sweep the sensors over the line
  delay(1000);
  int i;
  for(i = 0; i < 80; i++)
  {
    if ((i > 10 && i <= 30) || (i > 50 && i <= 70))
      motors.setSpeeds(-200, 200);
    else
      motors.setSpeeds(200, -200);
    reflectanceSensors.calibrate();

    // Since our counter runs to 80, the total delay will be
    // 80*20 = 1600 ms.
    delay(20);
  }
  motors.setSpeeds(0,0);

  // Turn off LED to indicate we are through with calibration
  digitalWrite(13, LOW);
  buzzer.play(">g32>>c32");

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Play music and wait for it to finish before we start driving.
  buzzer.play("L16 cdegreg4");
  while(buzzer.isPlaying());
   }
  {unsigned int sensors[6];

  // Get the position of the line.  Note that we *must* provide the "sensors"
  // argument to readLine() here, even though we are not interested in the
  // individual sensor readings
  int position = reflectanceSensors.readLine(sensors);

  // Our "error" is how far we are away from the center of the line, which
  // corresponds to position 2500.
  int error = position - 2500;

  // Get motor speed difference using proportional and derivative PID terms
  // (the integral term is generally not very useful for line following).
  // Here we are using a proportional constant of 1/4 and a derivative
  // constant of 6, which should work decently for many Zumo motor choices.
  // You probably want to use trial and error to tune these constants for
  // your particular Zumo and line course.
  int speedDifference = error / 4 + 6 * (error - lastError);

  lastError = error;

  // Get individual motor speeds.  The sign of speedDifference
  // determines if the robot turns left or right.
  int m1Speed = MAX_SPEED + speedDifference;
  int m2Speed = MAX_SPEED - speedDifference;

  // Here we constrain our motor speeds to be between 0 and MAX_SPEED.
  // Generally speaking, one motor will always be turning at MAX_SPEED
  // and the other will be at MAX_SPEED-|speedDifference| if that is positive,
  // else it will be stationary.  For some applications, you might want to
  // allow the motor speed to go negative so that it can spin in reverse.
  if (m1Speed < 0)
    m1Speed = 0;
  if (m2Speed < 0)
    m2Speed = 0;
  if (m1Speed > MAX_SPEED)
    m1Speed = MAX_SPEED;
  if (m2Speed > MAX_SPEED)
    m2Speed = MAX_SPEED;

  motors.setSpeeds(m1Speed, m2Speed);}
}
   
   else
   {
      // Run RC code.
      int throttle = pulseIn(THROTTLE_PIN, HIGH);
  int steering = pulseIn(STEERING_PIN, HIGH);

  int left_speed, right_speed;

  if (throttle > 0 && steering > 0)
  {
    // both RC signals are good; turn on LED
    digitalWrite(LED_PIN, HIGH);

    // RC signals encode information in pulse width centered on 1500 us (microseconds); subtract 1500 to get a value centered on 0
    throttle -= 1500;
    steering -= 1500;

    // apply deadband
    if (abs(throttle) <= PULSE_WIDTH_DEADBAND)
      throttle = 0;
    if (abs(steering) <= PULSE_WIDTH_DEADBAND)
      steering = 0;

    // mix throttle and steering inputs to obtain left & right motor speeds
    left_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) - ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);
    right_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) + ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);

    // cap speeds to max
    left_speed = min(max(left_speed, -MAX_SPEED), MAX_SPEED);
    right_speed = min(max(right_speed, -MAX_SPEED), MAX_SPEED);
  }
  else
  {
    // at least one RC signal is not good; turn off LED and stop motors
    digitalWrite(LED_PIN, LOW);

    left_speed = 0;
    right_speed = 0;
  }

  ZumoMotors::setSpeeds(left_speed, right_speed);
   }

#4

It is difficult to help you troubleshoot the issue without having more details about this error you are getting. Please copy and paste the entire error message or take a screenshot of the error message and post it here. Also, please format your code as stated in my previous post.

- Amanda


#5
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#include <ZumoMotors.h>
#include <ZumoBuzzer.h>
#include <Pushbutton.h>

#define LED_PIN       13 // user LED pin
#define PULSE_WIDTH_DEADBAND   25 // pulse width difference from 1500 us (microseconds) to ignore (to compensate for control centering offset)
#define PULSE_WIDTH_RANGE     350 // pulse width difference from 1500 us to be treated as full scale input (for example, a value of 350 means
                                  //   any pulse width <= 1150 us or >= 1850 us is considered full scale)


ZumoBuzzer buzzer;
ZumoReflectanceSensorArray reflectanceSensors;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON);
int lastError = 0;

// This is the maximum speed the motors will be allowed to turn.
// (400 lets the motors go at top speed; decrease to impose a speed limit)
const int MAX_SPEED = 400;

void setup()
{
  pinMode(LED_PIN, OUTPUT);

  // uncomment one or both of the following lines if your motors' directions need to be flipped
  //motors.flipLeftMotor(true);
  //motors.flipRightMotor(true);
}

bool thirdButtonPress_flag = false;
void loop()
{
   if (thirdButtonPress_flag == false)
   {
      // Run line following code.
      thirdButtonPress_flag = button.isPressed();
       // Play a little welcome song
  buzzer.play(">g32>>c32");

  // Initialize the reflectance sensors module
  reflectanceSensors.init();

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Turn on LED to indicate we are in calibration mode
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);

  // Wait 1 second and then begin automatic sensor calibration
  // by rotating in place to sweep the sensors over the line
  delay(1000);
  int i;
  for(i = 0; i < 80; i++)
  {
    if ((i > 10 && i <= 30) || (i > 50 && i <= 70))
      motors.setSpeeds(-200, 200);
    else
      motors.setSpeeds(200, -200);
    reflectanceSensors.calibrate();

    // Since our counter runs to 80, the total delay will be
    // 80*20 = 1600 ms.
    delay(20);
  }
  motors.setSpeeds(0,0);

  // Turn off LED to indicate we are through with calibration
  digitalWrite(13, LOW);
  buzzer.play(">g32>>c32");

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Play music and wait for it to finish before we start driving.
  buzzer.play("L16 cdegreg4");
  while(buzzer.isPlaying());
   }
  {unsigned int sensors[6];

  // Get the position of the line.  Note that we *must* provide the "sensors"
  // argument to readLine() here, even though we are not interested in the
  // individual sensor readings
  int position = reflectanceSensors.readLine(sensors);

  // Our "error" is how far we are away from the center of the line, which
  // corresponds to position 2500.
  int error = position - 2500;

  // Get motor speed difference using proportional and derivative PID terms
  // (the integral term is generally not very useful for line following).
  // Here we are using a proportional constant of 1/4 and a derivative
  // constant of 6, which should work decently for many Zumo motor choices.
  // You probably want to use trial and error to tune these constants for
  // your particular Zumo and line course.
  int speedDifference = error / 4 + 6 * (error - lastError);

  lastError = error;

  // Get individual motor speeds.  The sign of speedDifference
  // determines if the robot turns left or right.
  int m1Speed = MAX_SPEED + speedDifference;
  int m2Speed = MAX_SPEED - speedDifference;

  // Here we constrain our motor speeds to be between 0 and MAX_SPEED.
  // Generally speaking, one motor will always be turning at MAX_SPEED
  // and the other will be at MAX_SPEED-|speedDifference| if that is positive,
  // else it will be stationary.  For some applications, you might want to
  // allow the motor speed to go negative so that it can spin in reverse.
  if (m1Speed < 0)
    m1Speed = 0;
  if (m2Speed < 0)
    m2Speed = 0;
  if (m1Speed > MAX_SPEED)
    m1Speed = MAX_SPEED;
  if (m2Speed > MAX_SPEED)
    m2Speed = MAX_SPEED;

  motors.setSpeeds(m1Speed, m2Speed);}
}
   
   **else**
   {
      // Run RC code.
      int throttle = pulseIn(THROTTLE_PIN, HIGH);
  int steering = pulseIn(STEERING_PIN, HIGH);

  int left_speed, right_speed;

  if (throttle > 0 && steering > 0)
  {
    // both RC signals are good; turn on LED
    digitalWrite(LED_PIN, HIGH);

    // RC signals encode information in pulse width centered on 1500 us (microseconds); subtract 1500 to get a value centered on 0
    throttle -= 1500;
    steering -= 1500;

    // apply deadband
    if (abs(throttle) <= PULSE_WIDTH_DEADBAND)
      throttle = 0;
    if (abs(steering) <= PULSE_WIDTH_DEADBAND)
      steering = 0;

    // mix throttle and steering inputs to obtain left & right motor speeds
    left_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) - ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);
    right_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) + ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);

    // cap speeds to max
    left_speed = min(max(left_speed, -MAX_SPEED), MAX_SPEED);
    right_speed = min(max(right_speed, -MAX_SPEED), MAX_SPEED);
  }
  else
  {
    // at least one RC signal is not good; turn off LED and stop motors
    digitalWrite(LED_PIN, LOW);

    left_speed = 0;
    right_speed = 0;
  }

  ZumoMotors::setSpeeds(left_speed, right_speed);
   }
(sketch file) ZUMO COMBINED CODE - HUNTER - 01-30-17.ino:124:4: error: expected unqualified-id
   else
   ^
1 error generated.

The asterisks show where the error is.


#6

It looks like the curly braces are not matching up; you should check each open brace in your code and verify that they have a matching close brace while enclosing correct parts of the code. You might find this Arduino page, explaining why balancing braces in your code is important, helpful.

By the way, if you are not sure how to add code tags to your post(s), you can click on the pencil icon in the upper right-hand corner of the first post of this thread and view the raw source to see how I formated it.

- Amanda


#8

Hello,
Right now we are working on a zumo robot to preform line follow and then change to a rc car with one button push. We have a code that has verified but when we have the robot try it, it will preform the void setup but will not do anything after that. Can someone please help us as we are at a point of total confusion. Here is the code. Zumo_combinedCode.ino (5.5 KB)


#9

Hello Zumo World,
In our endeavors to combine a line follow and an rc code for Zumo, our students have put together the code shown below. The sequence works by turning Zumo on and pressing the Zumo button which engages the sensor array sequence, delays for a second and then enters the line follow sequence, until it gets another button push and senses an RC signal. The Zumo then runs in RC mode. The only hiccup to this is that after the first sensor array initialization, Zumo takes for the right in a circle and doesn’t seem to line follow. However, the next button push and RC signal does put it into RC mode. Does anyone see what’s wrong in our code that would not allow the line follow sequence to work properly? Thanks in advance for your help!

#include <ZumoMotors.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#include <ZumoMotors.h>
#include <ZumoBuzzer.h>
#include <Pushbutton.h>

#define THROTTLE_PIN   4 // throttle channel from RC receiver
#define STEERING_PIN   5 // steering channel from RC receiver
#define LED_PIN       13 // user LED pin

#define MAX_SPEED             400 // max motor speed
#define PULSE_WIDTH_DEADBAND   25 // pulse width difference from 1500 us (microseconds) to ignore (to compensate for control centering offset)
#define PULSE_WIDTH_RANGE     350 // pulse width difference from 1500 us to be treated as full scale input (for example, a value of 350 means
                                  //   any pulse width <= 1150 us or >= 1850 us is considered full scale)
                                  
ZumoBuzzer buzzer;
ZumoReflectanceSensorArray reflectanceSensors;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON);
int lastError = 0;



void setup()
{
  pinMode(LED_PIN, OUTPUT);

  // uncomment one or both of the following lines if your motors' directions need to be flipped
  //motors.flipLeftMotor(true);
  //motors.flipRightMotor(true);
}

void loop()
{
  int throttle = pulseIn(THROTTLE_PIN, HIGH);
  int steering = pulseIn(STEERING_PIN, HIGH);

  int left_speed, right_speed;

  if (throttle > 0 && steering > 0)
  
	{
    // both RC signals are good; turn on LED
    digitalWrite(LED_PIN, HIGH);

    // RC signals encode information in pulse width centered on 1500 us (microseconds); subtract 1500 to get a value centered on 0
    throttle -= 1500;
    steering -= 1500;

    // apply deadband
    if (abs(throttle) <= PULSE_WIDTH_DEADBAND)
      throttle = 0;
    if (abs(steering) <= PULSE_WIDTH_DEADBAND)
      steering = 0;

    // mix throttle and steering inputs to obtain left & right motor speeds
    left_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) - ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);
    right_speed = ((long)throttle * MAX_SPEED / PULSE_WIDTH_RANGE) + ((long)steering * MAX_SPEED / PULSE_WIDTH_RANGE);

    // cap speeds to max
    left_speed = min(max(left_speed, -MAX_SPEED), MAX_SPEED);
    right_speed = min(max(right_speed, -MAX_SPEED), MAX_SPEED);
	}
	else
	{
		
		// Play a little welcome song
  buzzer.play(">g32>>c32");

  // Initialize the reflectance sensors module
  reflectanceSensors.init();

  // Wait for the user button to be pressed and released
  button.waitForButton();

  // Turn on LED to indicate we are in calibration mode
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);

  // Wait 1 second and then begin automatic sensor calibration
  // by rotating in place to sweep the sensors over the line
  delay(1000);
  int i;
  for(i = 0; i < 80; i++)
  {
    if ((i > 10 && i <= 30) || (i > 50 && i <= 70))
      motors.setSpeeds(-200, 200);
    else
      motors.setSpeeds(200, -200);
    reflectanceSensors.calibrate();

    // Since our counter runs to 80, the total delay will be
    // 80*20 = 1600 ms.
    delay(20);
  }
  motors.setSpeeds(0,0);

  // Turn off LED to indicate we are through with calibration
  digitalWrite(13, LOW);
  buzzer.play(">g32>>c32");
  
  delay(1000);
  


  // Play music and wait for it to finish before we start driving.
  buzzer.play("L16 cdegreg4");
  while(buzzer.isPlaying());
 unsigned int sensors[6];

  // Get the position of the line.  Note that we *must* provide the "sensors"
  // argument to readLine() here, even though we are not interested in the
  // individual sensor readings
  int position = reflectanceSensors.readLine(sensors);

  // Our "error" is how far we are away from the center of the line, which
  // corresponds to position 2500.
  int error = position - 2500;

  // Get motor speed difference using proportional and derivative PID terms
  // (the integral term is generally not very useful for line following).
  // Here we are using a proportional constant of 1/4 and a derivative
  // constant of 6, which should work decently for many Zumo motor choices.
  // You probably want to use trial and error to tune these constants for
  // your particular Zumo and line course.
  int speedDifference = error / 4 + 6 * (error - lastError);

  lastError = error;

  // Get individual motor speeds.  The sign of speedDifference
  // determines if the robot turns left or right.
  int m1Speed = MAX_SPEED + speedDifference;
  int m2Speed = MAX_SPEED - speedDifference;

  // Here we constrain our motor speeds to be between 0 and MAX_SPEED.
  // Generally speaking, one motor will always be turning at MAX_SPEED
  // and the other will be at MAX_SPEED-|speedDifference| if that is positive,
  // else it will be stationary.  For some applications, you might want to
  // allow the motor speed to go negative so that it can spin in reverse.
  if (m1Speed < 0)
    m1Speed = 0;
  if (m2Speed < 0)
    m2Speed = 0;
  if (m1Speed > MAX_SPEED)
    m1Speed = MAX_SPEED;
  if (m2Speed > MAX_SPEED)
    m2Speed = MAX_SPEED;

  motors.setSpeeds(m1Speed, m2Speed);
}
ZumoMotors::setSpeeds(left_speed, right_speed);
}

#10

I merged hunterjos4’s post with this thread since his question is related to the original issue.

Since it sounds like you are both working on the same robot, I would expect you to be working on the same program. Is that the case?

@hunterjos4
Can you clarify what you mean by the Zumo not doing anything after your program executes setup() (e.g. the robot doesn’t move after it stops playing music)? Can you verify that your Zumo is working by running the LineFollower example?

@sobinn
I briefly looked over your code, which is completely different from your original, and noticed a few things wrong. Mainly, you should not have the setup code for line following in the main loop, because (when throttle and steering are equal to or less than 0), the reflectance sensors will repeatedly undergo the initialization and calibration phase (as well as waiting for the user button to be pressed) instead of following the line. Since the line following portion of your original code was working, I suggest going back to that and implementing your RC mode from there.

By the way, you mentioned pushing a button to put your Zumo into RC mode, but it looks like you are only using the throttle and steering channels of your RC to run the RC code. If that is the case, you might consider replacing if (ZUMO_BUTTON = 1) with if (throttle > 0 && steering > 0) and if (ZUMO_BUTTON = 0) with else in your original code.

-Amanda


#11

Yes I am the student working on the robot and sobinn is my teacher advising the project.


#12

Have you tried any of the things I suggested in my last few posts? It is difficult to help you troubleshoot without knowing what you try and if you are working on a single program.

- Amanda


#13

We have but they didn’t work. We feel like we have found a solution and are going to try it out today. Instead of using the bool third button press we are going to use an if statement for if the robot gets a signal from the remote to the transmitter.


#14

Greetings; I am interested in doing exactly the same as you are doing. Did you get the line follower and RC control code to work?


#15

Yes we actually did.


#16

When I get to a better computer I can try to send you a sample of our code. It won’t be till 3 though.