28BYJ-48 5V Stepper Motor

This stepper motor was bought from taobao.com, along with a UNL2003 driver board. I knew nothing about the stepper before so googled online and found the article from this blog, this article showed procedures on how to disclose the motor. The photos he took showed the structure of the motor clearly how it worked.

Because the step angle of the rotor is 5.625, so it needs 64 pulses for the rotor to make a full rotation, and, what's more, this type of motor is reducing one, the slow down ratio is 1:64, so,  there should be 64*64 = 4096 pulses to rotate at 360 degrees for the output shaft.

The internal picture of ULN2003 looks as below:

The ULN2003 acts as a relay, it is not a true stepper driver at point of my view :-).  Since the frequency of arduino's IO is about 500Hz, it would take 8 seconds

approximately to make the shaft turn a round, so the max speed is about 7RPM, oooops, it runs toooo slowly and is not acceptable at all in a real world application.