after a horrible week of ordering and a bunch of wrong shipments

science_geek

I have recieved my stepper motors in the mail. I ordered 3 unipolar stepper motors with a controller for each, turns out that after some research the controller i order is for a bipolar stepper motor. i have a project due this friday may 1. is there anyway to rig the motors or the controller to make them compatable. the reason i found out about the controller being wrong, was because i saw it on sparkfun after i order from the one place. Also is there a way for me to quickly throw together a controller if they are not at all compatible. any help is deeply appreciated.

rjo_

What are you using for a microcontroller... I can show you how to do it with a Prop and some stuff you can get at RadioShack... I'll be out until tomorrow night...

science_geek

yes, thank you so much, any help you can offer is great, can you write me up a parts list so that i can get the parts soon, also if you hace a schematic that woulb be great, i am using the prop, if you have any sample code or psuedo code would be most beneficial, this is due this friday and the mill is almost done, im expecting the motors tomorrow(monday) and on tuesday it should all be done and ready for a test (i hope i will get lucky on this one)

science_geek

ok, just got the motors, they are 6 wire, i also got 3 bipolar controllers, i was reading around and read something that you can run a unipolar motor off a bipolar controller, is this true, if so, how do i do it, it would only be temporary until i can get a more permenant solution unless it works good

Franklin

Which motors, which controllers, reading around where? (links to what you read) If you help us perhaps we could help you.

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- Stephen

science_geek

i got 3 unipolar 12v .4amp 1.8degree step angle 6 wire stepper motors, the controllers i have are bipolar stepper motor controllers from here (http://www.sparkfun.com/commerce/product_info.php?products_id=8368) i am going to use a deep cycle marine lead acid battery to drive them, i was wondering if the controller would work, but now im thinking im just going to use some npn transistors and a spare prop to drive 12 of them(4 for each motor) i was experimenting out in my garage and i think i can make a super simple driver from a prop and a wireless serial input from another prop. now to find out if radioshack has fets or transistors of this size

kwinn

Are you sure the motors are unipolar? Usually unipolar motors have 4 wires, bipolars 6.

James Long

kwinn said...
Are you sure the motors are unipolar? Usually unipolar motors have 4 wires, bipolars 6.

There is a 4 wire bipolar stepper. I helped a guy on Sparkfun's site with this.

The polarity of the winding change as it revolves (hence bipolar). You can search for 4 wire bipolar stepper, and find some diagrams. A 4 wire bipolar requires an H bridge to run (since the polarity changes on the windings).

Unipolar have 5 wires (one is ground), bipolar have 4 or 6 (the 6 wire version has 2 grounds, one for each winding).

I did an extensive search, but you are free to do your own if you wish.

James L

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James L
Partner/Designer

Lil Brother SMT Assembly Services

Bob Lawrence (VE1RLL)

Borrowed From This URL(see diagrams): electojects.com/motors/stepper-motors-2.htm

The 4-wire motor can only be driven by bipolar waveforms. The 6-wire motor, the most common arrangement, is intended for unipolar drive because of the center taps. Though, it may be driven by bipolar waves if the center taps are ignored. The 5-wire motor can only be driven by unipolar waves, as the common center tap interferes if both windings are energized simultaneously. The 8-wire configuration is rare, but provides maximum flexibility. It may be wired for unipolar drive as for the 6-wire or 5-wire motor. A pair of coils may be connected in series for high voltage bipolar low current drive, or in parallel for low voltage high current drive.

A bifilar winding is produced by winding the coils with two wires in parallel, often a red and green enameled wire. This method produces exact 1:1 turns ratios for center tapped windings. This winding method is applicable to all but the 4-wire arrangement above.

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Aka: CosmicBob