http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2009-01-08T11:13:40-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t1360.html 2009-01-08T11:13:40-08:00 Hi , I have bought a stepper motor which is having only 4 wires and also small in size. Usually stepper motors will be having 5 or 5 wires with 2 pair of coils and 1 common,so we can easily find out the terminals. but in this how I can find out the common and other terminals, I want to interface to the 8051 controller for the complete PROXIMITY ROBOT project since with that stepper motor I can't make the Choasis and other thing, since it is big in size. CAN ANY ONE HELP IN THIS MATTER.REGARDS n THANKSSanath Mcx http://www.8051projects.net/forum-t1360.html 2009-01-08T11:13:40-08:00 SANATH EMBEDDED Thanx alot Ajay,i didn't know about this Bi-Polar Stepper Motor. Now I will try to find the wires for corresponding coils. http://www.8051projects.net/forum-t1360.html 2009-01-08T11:13:40-08:00 Ajay Hi sanath,I think you've got a Bipolar stepper motor which has two coils separated with no common. it has 4 wires instead of 5 or 6 wires in case of uni polar stepper motor. Below is a digram of Bipolar stepper motorTo check which wire for which coil.. simply do the connectivity test http://www.8051projects.net/forum-t1360.html 2009-01-08T11:13:40-08:00 Ajay soon i am going to write a new tutorial for stepper motors...i only discussed about Unipolar Stepper motors (5 or 6 wires). But i think i have to write for Bipolar motors too http://www.8051projects.net/forum-t1360.html 2009-01-08T11:13:40-08:00 ۞ TPS ۞ i have a deiled info on stepper motors soon i will share with u http://www.8051projects.net/forum-t1360.html 2009-01-08T11:13:40-08:00 Ajay I have already put all the information about stepper motors in my tutorial.. please take a look. if you think something is missing please tell me