Stepper motor troubles, i need ideas.

Hey everyone, im new to the forum. I came here to seek help running stepper motors with my arduino. I have a 6 wire unipolar SM, ive isolated the different coils with my ohm meter and this is what ive done so far... the stepper hookup connector is (red,brown,blue,yellow,white,white), red/brown/white = one coil with center tap, blue/yellow for the other. Ive hooked it up with a ULN2003A.... O1 = Red O2 = Brown O3 = Blue O4 = Yellow with whites on common.

and the arduino at 1,2,3,4 to the ULN2003A at I4,I3,I2,I1

I ran a simple program in arduino that pulses... 1000 0100 0010 0001 The stepper takes two steps forwards and two steps back. Ive reversed the motor coils and it still does the same thing, ive reversed the logic inputs and still the same result. Im really having a hard time with this, anyone have any suggestions? I'm kinda stumped on where i should go from here...

Thanks. -Nick

I ran a simple program in arduino that pulses…
1000
0100
0010
0001

Well you’re wrong with that sequence, look at the link below:
http://www.google.fr/imgres?imgurl=http://www.8051projects.net/stepper-motor-interfacing/stepper-coils.jpg&imgrefurl=http://www.8051projects.net/stepper-motor-interfacing/introduction.php&usg=__MhQYun-Tg-EqsPLhKko5PLE6P1E=&h=279&w=289&sz=26&hl=fr&start=9&zoom=1&um=1&itbs=1&tbnid=6FhvXUU8gS1CFM:&tbnh=111&tbnw=115&prev=/images%3Fq%3Dstepper%2Bmotor%2Bunipolar%26um%3D1%26hl%3Dfr%26newwindow%3D1%26client%3Dfirefox-a%26rls%3Dorg.mozilla:fr:official%26tbs%3Disch:1&ei=-rdPTeuyAYX2sgaM4_yeDw

Or for an alternative explanation see:- http://www.thebox.myzen.co.uk/Workshop/Motors_3.html

i assume you meant i need to run... 1100 0110 0011 1001

I thought this was just a higher torque version what i originally ran? I still get the same problem, the shaft just goes back and forth, this time more violently. Do you think the problem is in the sequence or in the wiring?

Thanks for your help. -Nick

Do you think the problem is in the sequence or in the wiring?

Either but they are both the same thing if you think about it.

Try swapping motor pairs, there are a lot of combination to try.