stepper motor from epson printer

hey guys!
i’m wondering about the manner that allow us to identify and programme a stepper motor! :confused:
well!! i got it from a broken epson printer the reference is stp-42d221-03 it’s an unipolar stepper with 5 wires. ( you can see it in the picture below )
i tried to find the com. wire using the ohmmeter and i identified it, but the other wires i find it difficult to know the a phase and the a\ phase , the b phase and the b\ phase because of the uncolored wires of the motor.
when i tried some sequences to command my stepper using an arduino mega with uln2003a, the motor stay blocked but when i connect some wires directly to my 12v generator; every time when i change the connection wires the motor do some steps…
i don’t know how to find the right way to make my stepper works ** :(**
images (1).jpg

Stepper motors are a whole subject unto themselves. They need a proper circuit to give them the pulses to run. This circuit can be controlled from a single board computer like the Arduino. You must first learn the difference in stepper motors and then find a driver circuit that will operate that stepper. Then you will have to learn how to interface that circuit to a SBC. I suggest that you start with the site found at: then branch out from there.

thank you but! the problem here is that i can't find the solution to identify the wires :( i followed all the steps written in some document ( it content the same information that you give it to me :) ) i tried with the uln2003 circuit and l293d H-bridge ( i used the example of the arduino stepper librarie ) but the result is the same the motor ain't work because of the wires connection i guess :confused:

You really need to know how much current (amps) the motor needs.

If you measure the resistance of the coils you should be able to work out the internal wiring arrangements. There should be a wire to each end of the two coils (4 wires) and the 5th wire should go to the centres of the two coils.

That should enable you to connect correctly to the ULN2003 driver chip. However if the chip can't handle enough current the motor may not move at all.

In some 5-wire motors it is possible to separate the 5th wire into two so that you have a 6-wire motor which can be used as a bipolar motor by ignoring the two wires to the centres of the coils. But this only works if you can separate the wires. Just in case you can you may find stepper motor basics useful - but it does not deal with 5-wire steppers.

There are lots of Threads about 28BYJxxx 5-wire motors that you may find useful.


thank you guys for your comments :slight_smile:
it was a power problem i’m using a 12v generator when my steppers need 24v and 2.4A

No they don't that power level will cook them. 24V x 2.4A = 70W

24V 2.4A implies 10 ohm windings, and the typical printer motor will handle at most 10W, ie about 10V 1A.

Try something like 12V and ULN2803 with 2 channels paralleled per motor phase - that might just cope.

Anyway what is the actual winding resistance?

Hello people,

I'm having trouble making connections of this engine wired Arduino used the IC ULN2003 anyone has any png that demonstrates this wiring diagram

First measure the winding resistances with a multimeter and report back. Just because there are 5 wires doesn't prove its a 5-wire motor, sometimes one wire is the earthing lead to the motor frame and nothing to do with the windings.

Multimeter time.

Thanks for the help MarkT, The motor has 5 wires and one of them has the color blue the others are gray. I’ll take the blue wire with number 1 and the other in ascending order.
I used the multimeter in the range of 200 ohms

With the positive tip fixed on the wire 1 and ranging up to the wire 5 got the following values

1 - 2 = 5.4 ohms
1 - 3 = 5.4
1 - 4 = 5.4
1 - 5 = 2.8

2 - 3 = 5,4
2 - 4 = 5,4
2 - 5 = 2,8

3 - 4 = 5,4
3 - 5 = 2,8

4 - 5 = 2,8

a) doing a test called the wire 5 v with 12v put on other wires assay plate in the following order (1-3 - 2-4) when touched down following order the engine to perform the steps clockwise

b) I found a tutorial explaining ULN2003AN how to use and worked perfectly with ic

c) is that it is possible to change this motor for bipolar cut this trail in the photo below?

Not if the two windings are commoned. Bipolar drivers require two independent windings.


Whatever you do, I hope you didn't/don't remove the rotor from the stator...

At one time, this was considered a big no-no when it comes to steppers, because removal of the rotor (which is a special permanently-magnetized part) from the stator (which is composed of electromagnets with steel cores) would interrupt the flux-coupling, causing the rotor to become somewhat demagnetized, and thus effecting the strength of the motor.

This was mainly because of the type of magnetic material used in the rotor; older material formulations were affected by this problem more. I'm not sure how newer rotor formulas fair with disassembly, but if you can avoid the risk, it might be best.

This discussion gives some details:

The last comment seems to indicate that modern motors (with modern magnet materials) aren't affected, but that you need to check the service manual (or maybe the datasheet) for the motor to know what materials were used.

That was AlNiCo, a woefully low coercivity permanent magnet material (but about the best available till rare-earth magnets were discovered). AlNiCo motors could be permanently demagnetized by over-current events too, not just taking them apart without a keeper.

Any motor with ferrite or rare-earth magnets is robust against disassembly. Ferrite isn't a very strong permanent magnet, but is used in a lot of cheap motors because it is cheap. Rare-earth magnets (usually NdFeB) are used in high-torque motors (fairly common for steppers these days), and are the best performing permanent magnets.