Stepper motor NOT moving on flat ground

Hi, my stepper motor is a 5v 28BYJ-48 stepper motor. I am using a ULN2003 Darlington Driver (stepper motor driver). I am also using a velleman Arduino Mega ADK 2560. Whenever I put my project on the floor, the motors do NOT move. I am wondering if it is not strong enough.

Speed: 60

Here is my code:

#include <arduino.h>

#include <Stepper.h>

int stepsPerRevolution = 200;  // change this to fit the number of steps per revolution
// for your motor

// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 46, 50, 48, 52);


void setup() {
  // set the speed at 60 rpm:
  myStepper.setSpeed(60);
  // initialize the serial port:
}

void loop() {
  // step one revolution  in one direction
  myStepper.step(-stepsPerRevolution);

The 28BYJ-48 is a geared stepper with a 32 step per rev motor and 64:1 gear reduction, so it takes 2048 steps for 1 shaft rotation. Do the wheels turn if you hold it off the floor? BTW: About 12 to 13 RPM is all I have gotten out of them without missing steps, about 450 steps per second. Also, if you are trying to power the motor from the Arduino's 5V pin, there is probably not enough current, you really need a 5V source that can supply at least 600 mA.

Yes, the wheels move when off the ground.

Good to know that the stepper is connected to a wheel.

Can you tell us about the size of the wheel(s), and the shape and weight of whatever the motor is supposed to be driving ("the Project"), or is that confidential information?

How much torque do you need at the wheels?

I did a little search and found torque rating for the 28BYJ48 motor as about 0.08Nm for 5V 200mA full-step operation.

This will be pull-out torque, dynamic torque will be a lot less, so I'd assume 0.03Nm or so as a rough guess.