Simple demo code for a camera slider: https://www.thingiverse.com/thing:5405269

camera_slider.ino

#include <AccelStepper.h>

const int speed = 700;
const double accl = 0.05;

AccelStepper stepper = AccelStepper(AccelStepper::DRIVER, DD3, DD2);
long prev_speed;

void setup()
{
  stepper.setMaxSpeed(speed);
  prev_speed = 0;
}

void loop()
{
  int x = analogRead(A2);

  x = map(x, 0, 1023, -1*speed, speed);

  x = accl*x + (1-accl)*prev_speed;

  if (x > speed/10 || x < -speed/10) {
    stepper.setSpeed(x);
  } else {
    stepper.setSpeed(0);
  }
  stepper.runSpeed();
  prev_speed = x;
}