This is my first stepper motor project where the I have used NIPPON PF35T-48L4 (http://robotalk.codecake.com/wp-content/uploads/2008/08/PF35T-48L4.pdf) unipolar motor which I controlled from a PC through the Parallel Port (LPT1, DB25). I simply used a ULN2003A (http://robotalk.codecake.com/wp-content/uploads/2008/08/ULN2003A.pdf) IC which uses 7 Darlington Transistor Array to amplify the input current comming from the port. This 16-pin IC is capable to take TTL input and the output load may have high voltage upto 50V. I wrote small program in Visual Basic 6 using inpout32.dll (http://logix4u.net/Legacy_Ports/Parallel_Port/Inpout32.dll_for_Windows_98/2000/NT/XP.html) driver.
Here is a screenshot for the unipolar stepper motor and the driver IC ULN2003A:
(http://robotalk.codecake.com/wp-content/uploads/2008/08/motor-and-driver-ic.jpg)
Here is the schematic of my stepper motor driver:
(http://robotalk.codecake.com/wp-content/uploads/2008/08/stepper-driver-schematic.gif)
It is recommended to connect a 6.2V zener diode between the power supply and VDD (Pin 9) on the chip, to absorb reverse (or “back”) EMF from the magnetic field collapsing when motor coils are switched off.
To rotate the motor anti-clock wise, the step sequence sent to the parallel port is as follows:
STEP-1 0001 1
STEP-2 1001 9
STEP-3 1000 8
STEP-4 1010 10
STEP-5 0010 2
STEP-6 0110 6
STEP-7 0100 4
STEP-8 0101 5
Here is the live video of how the motor rotates:
[youtube]hQlG9tHk41w[/youtube]
To learn how a unipolar stepper motor works, read more (http://www.cs.uiowa.edu/~jones/step/types.html#unipolar). Here is another reference to Stepper Motor Controller (http://www.doc.ic.ac.uk/~ih/doc/stepper/control2/connect.html).
For more info about Microcontroller, Stepper Motor, Analog to Digital Converter, Sensors and other Roboric related topics visit http://robotalk.codecake.com/ (http://robotalk.codecake.com/).
Tags: inpout32.dll (http://robotalk.codecake.com/tag/inpout32dll/" rel=tag), Motor Control (http://robotalk.codecake.com/tag/motor-control/" rel=tag), Parallel Port (http://robotalk.codecake.com/tag/parallel-port/" rel=tag), Stepper Motor (http://robotalk.codecake.com/tag/stepper-motor/" rel=tag), ULN2003 (http://robotalk.codecake.com/tag/uln2003/" rel=tag)