Hi !
Before mentioning the question , I have to tell I did search about this . The methods were :
1- connect LED and spin the motor . If the led spins , you've found a pair (best method , I think , not only determines pairs but also + and - )
2- spin , remember how hard it is . Connect 2 random wires and see if it's harder . if it is , you've found a pair (I've done this before , it turned SOFTER )
Now , I'm trying this with one of those little ones in dvd writers . Problems :
method 1 - this motor is so small I bet it won't be able to turn on ANYTHING if I do THAT . Still possible with a transistor , though .
method 2- confused - is it supposed to turn softer or harder if I'd find a pair ?
method 3 - Can I use the Multimeter-Ohm-test method ?
Thanks in advance !
method 3 - Can I use the Multimeter-Ohm-test method ?
Yes that is the best way.
but also + and -
No the coil is designed to have the current first flowing in one direction and then the other. There is no + and - connections.
So I just find the 2 pairs and connect it ? I thought the 2 wires on each pair were different (because on https://dlnmh9ip6v2uc.cloudfront.net/assets/8/2/1/e/4/50e62d4ace395f627e000004.jpg there are red and black wires , I thought + and - are different)
Thanks for helping ! 
Once you have identifed the two pairs you have three ways to reverse the
sense of the motor (other than using software), by swapping one pair for the
other pair, or for switching the wires within one pair - so basically the motor
will work however you connect it so long as you have identifed the pairs.
Hi , thanks , so basically there is no difference which pair is connected as A and which is B , right ?
I wanted to use them for a CNC (a fairly minuscule one XD 5cm x 5cm) and I decided to use these little ones because there is a ready made mechanism inside the DVD writers , but there is no data sheet for these so I had to figure it out .
Just as in a 3-phase motor the phases are equivalent, in a 2-phase motor
(which is what a bipolar stepper is) the phases are equivalent. BTW you
can get 3- and 5-phase stepper motors, rather exotic, but less noise/vibration.
With 5-phase you have to get the phases in the right order since there are
wrong orders (with 2 and 3 phase the order only affects direction).
Hi , thanks for helping ! I have some 5 wired ones that I can turn into a 4 wired but for some reasons I'd go with the bipolars in dvd writers :
1- In another topic I asked about the 5 wired ones (with uln2003) and they said it does not support step and direction (perhaps because of uln2003 . maybe I could use 5 wired with bipolar drivers (ignoring the common(mine has a mini board where I could turn it to a 6 wired then again turn it to 4 wired)))
2- it has a metal gear (might not be bad till now , but) : which I cant take off .
3- the ones in dvd writers have ready mechanisms .
on the other hand these would allow me to make a bigger cnc (maybe workspace of an A4 $) ) but even 5x5 cm is enough (due to the fact that its my first electronic 'project' that Im making myself , my first cnc , my first meeting with steppers , not wanting to give lots of money and the fact that 5x5 is enough for now).