Stepper motor is a variable reluctance DC motor. When correct input sequence of signal is given to the motor, it starts rotation in steps. (For more detail refer Unipolar Stepper motor interfacing with microcontroller AT89C51).
ULN2003 is high voltage, high current Darlington arrays each containing seven open collector Darlington pairs with common emitters. Here it is used as a current driving IC. This IC is required because stepper motor require more than 60mA current and since controller doesn’t work at this current rating so this IC provides high current to the stepper motor.
In the circuit port P2 as output port which provide input sequence to four input pins of ULN3003 and output of ULN2003 drives the motor.
Input sequences are same as in previous project which are
And for half step size