#define dirPin 2
#define stepPin 3
#define endPin 4

long maxRange = 35000; // motor maximum excursion range - 35000
int brakeRange = 400; // motor lowSpeed range
int lowSpeed = 2000;     // motor lower speed
int highSpeed = 2800; // motor higher speed
int inversionBreak = 10000; // motor pause time - 10000

long stepSpeed = 0;
bool dir = true;
long counter = 0;
bool rodEnd = false;
long brakeFactor = 0;

void setup() {
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  pinMode(endPin, INPUT);
  digitalWrite(dirPin, dir);

  while(!rodEnd) {    
    counter++;
    if(counter <= brakeRange) {
      brakeFactor = (lowSpeed / brakeRange) * counter;
      stepSpeed = (highSpeed + brakeFactor > highSpeed + lowSpeed) ? highSpeed + lowSpeed : highSpeed + brakeFactor;
    } else {
      stepSpeed = highSpeed;
    }

    digitalWrite(stepPin, HIGH);
    delayMicroseconds(stepSpeed);
    digitalWrite(stepPin, LOW);
    delayMicroseconds(stepSpeed);

    if(digitalRead(endPin)) {
      rodEnd = true;
      counter = 0;
    }
  }
}

void loop() {
  if(!dir) {
    counter++;
    if(counter >= maxRange) {
      dir = !dir;
      digitalWrite(dirPin, dir);
      delay(inversionBreak); 
    } else {
      if(counter >= maxRange - brakeRange) {
        brakeFactor = (lowSpeed / brakeRange) * (maxRange - counter);
        stepSpeed = (highSpeed + brakeFactor > highSpeed + lowSpeed) ? highSpeed + lowSpeed : highSpeed + brakeFactor;
      } else if(counter <= brakeRange) {
          brakeFactor = (lowSpeed / brakeRange) * counter;
          stepSpeed = (highSpeed + brakeFactor > highSpeed + lowSpeed) ? highSpeed + lowSpeed : highSpeed + brakeFactor;
      } else {
        stepSpeed = highSpeed;
      }
      
      digitalWrite(stepPin, HIGH);
      delayMicroseconds(stepSpeed);
      digitalWrite(stepPin, LOW);
      delayMicroseconds(stepSpeed);
    }
  } else {
    counter--;
    if(counter <= 0) {
      dir = !dir;
      digitalWrite(dirPin, dir);
      delay(inversionBreak);
    } else {
      if(counter >= maxRange - brakeRange) {
        brakeFactor = (lowSpeed / brakeRange) * (maxRange - counter);
        stepSpeed = (highSpeed + brakeFactor > highSpeed + lowSpeed) ? highSpeed + lowSpeed : highSpeed + brakeFactor;
      } else if(counter <= brakeRange) {
          brakeFactor = (lowSpeed / brakeRange) * counter;
          stepSpeed = (highSpeed + brakeFactor > highSpeed + lowSpeed) ? highSpeed + lowSpeed : highSpeed + brakeFactor;
      } else {
        stepSpeed = highSpeed;
      }
      
      digitalWrite(stepPin, HIGH);
      delayMicroseconds(stepSpeed);
      digitalWrite(stepPin, LOW);
      delayMicroseconds(stepSpeed);
    }
  }
}