As stepper motors become increasingly popular in electronic products, they will continue to hold a stronghold in the electronics market. Everywhere, stepper motors are used as actuators for easy control ranging from surveillance cameras to complex CNC machines and robots. This tutorial demonstrates the 28-BYJ48 stepper motor, commonly available and cheaply. We'll also explore the ULN2003 stepper module that enables us to interface the 28-BYJ48 with an Arduino controller. The previous project we completed was Interface Stepper Motor with Arduino, which allowed you to control the rotation angle of the stepper motor via the serial monitor. In this project, we are going to rotate a stepper motor using an Arduino and a potentiometer. The potentiometer will rotate clockwise when you turn it clockwise and anticlockwise when you turn it the other way.

Let's take a look at the 28BYJ48 stepper motor. Its wires are all fancy colors and are not connected to a normal DC motor, it is just the opposite. Why? Before understanding this, we need to know how steppers work and what their specialties are. A stepper motor does not rotate, but its movements are linear, hence it is commonly referred to as a step motor.

Each step will be taken one after the other. A series of coils are embedded in these motors, and these coils have to be wired in an energized manner in order for the motor to rotate. A motor takes steps when each coil is energized, and a series of the energizations makes the motor turn continuously, thus causing it to spin. Here is what these coils in the motor look like to determine exactly where they come from.

A five-lead unipolar coil arrangement can be seen on the motor. Each coil requires an individual sequence of energizing. A + 5V supply will be applied to the red wires while the rest of the wires will be pulled to ground for triggering the respective coils. These coils are energized in a particular sequence using a microcontroller such as Arduino. Now that I think about it - I have no idea why this motor is called 28-BYJ48. It doesn't appear that this motor has any technical reason for its title; perhaps we should delve further into it. In the picture below we have taken some important technical data from the data sheet of this motor.

Here is an example that shows using the Arduino Stepper Library to control a stepper motor using a potentiometer (or other sensor) on analog input 0. With either unipolar or bipolar motors, the stepper can be controlled via digital pins 8, 9, 10, and 11. If you are using a unipolar stepper, you will connect the Arduino board to a U2004 Darlington array; if you are using a bipolar motor, you will connect it to a SN754410NE H-bridge. What are the reasons for the need for Driver Modules for Stepper Motors? A driver module is usually required to operate most stepper motors. We cannot drive the motor with the controller module (In our case Arduino) because the controller's I/O pins won't deliver enough current. So, we will use the ULN 2003 stepper motor driver as an external module. Different types of driver modules are used for different types of motors so the rating will change accordingly. For any driver module, the primary function will be to source/sink sufficient current for the motor to operate. Using Potentiometer and Arduino to control a stepper motor is shown in the circuit diagram above. The ULN2003 driver module and the 28BYJ-48 Stepper motor were used. A driver module connected to the Arduino board's digital pin 8 is used to energize the four coils on the stepper motor. The

Arduino 5V pin is used to power the stepper motor. We will rotate the Stepper motor based on the values of a potentiometer connected to A0. If you are connecting some load to the stepper motor, then power the driver with an external power supply. The motor has been used on the +5V rail of the Arduino Board for demonstration purposes. Make sure the Arduino is connected to the ground of the Driver module as well.