Trying to use servos in a class

Projects Programming
1

I am trying to use the servo library inside a class so that I can make mutiple instances of my class with each one using a different servo pin. I can figure out how to do this without getting scope errors in the code. The three files and are below and they are all in an attached zip file.

MyOBstacle.ino

#include <Wire.h>
#include "obstacle.h"


OBSTACLE c(11);

/*****************************************************************************/
void setup()
{
  Wire.begin();
  Serial.begin(115200);
  while (!Serial);
  delay(250);
}

/*****************************************************************************/
void loop()
{
}

obstacle.cpp

#include <arduino.h>
#include "Obstacle.h"
#include <VL53L0X.h>
#include <Servo.h>

VL53L0X tof;

const int CENTER = 88;
const int SPEED = 150;
const int SCANMAX = CENTER + 50;
const int SCANMIN = CENTER - 50;
const int MIN_DISTANCE = 400;
const int LEFT = 0;
const int RIGHT = 1;
const int STRAIGHT = 2;

int OBSTACLE::GetPos()
{
  return _pos;
}

void OBSTACLE::SetPos(int p)
{
  _pos = p;
}

int OBSTACLE::GetDist()
{
  return _dist;
}

int OBSTACLE::GetDir()
{
  return _dir;
}

OBSTACLE::OBSTACLE(int servoPin)
{
  Servo srv;
  srv.attach(servoPin);

  //  tof.setAddress(0x29);
  //  tof.setTimeout(100);
  //  if (!tof.init())
  //  {
  //    Serial.println("Failed to detect and initialize sensor!");
  //    while (1);
  //  }
  //  tof.startContinuous();
}

boolean OBSTACLE::Tick()
{
  static int p;
  int incDec = 4;

  int mm = 0; // = tof.readRangeContinuousMillimeters();                  // get the distance
  //
  //  if (tof.timeoutOccurred())
  //    Serial.print(" TIMEOUT");
  //
  //  Serial.print(mm);                                               // print the distance

  p += incDec;                                                        // inc or dec depencing on value of incDec

  if (p > SCANMAX)                                                    // if we exceed the max
  {
    p = SCANMAX;                                                      // set it to the max
    incDec = -4;                                                      // start decrimenting
  }

  if (p < SCANMIN)                                                    // if we are below min
    p = SCANMIN;                                                      // start incrementing
  incDec = 4;

  OBSTACLE::SetPos(p);                                                // set the next servo position
  srv.write(p);                                                       // move the servo

  _pos = p;                                                           // set pos
  _dist = mm;                                                         // set Dist

  if (_pos < 90)                                                      // set dir left or right
    _dir = LEFT;
  else
    _dir = RIGHT;

  if (mm < MIN_DISTANCE)                                              // is there an obstacle?
    return true;
  else
    return false;
}

obstacle.h

#ifndef OBSTACLE_H
#define OBSTACLE_H
#include <arduino.h>

class OBSTACLE
{
private:
int _pos;
int _dist;
int _dir;

public:
int GetPos();
void SetPos(int p);
int GetDist();
int GetDir();
OBSTACLE(int servoPin);
boolean Tick();
};

#endif
MyObstacle.zip (1.5 KB)

2

?can not?

3

I made a servo based class some days ago.
May be you find it helpfull

https://werner.rothschopf.net/microcontroller/202207_millis_slow_servo.htm

4

Srv needs to be a class variable. You have declared it local to a constructor.

5

Thanks wildbill, I'll see if I can do tomorrow.

6

Just move this line from the constructor to the class declaration. It can be a private member variable.

In OBSTACLE::Tick() you don't have to use the "OBSTACLE::" qualifier on the "SetPos()" member function.

7

Thank you for the help.
I moved Servo srv ; to the class declaration and the #include <Servo.h> to the obstacle.h class header file.

It works nicely.

8

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