Splitting AC-DC wall-adapter power supply to power arduino and stepper motor

[kotnico]

A stepper motor is normally characterised by rated current & coil resistance, not voltage.

In your case that's 330 mA and 32.6Ω. That'd indeed give you some 250 mA after L298N losses. Note: the L298N does NOT regulate current, at all. That's part of the problem of using it for steppers.

alright i understand now thanks

You always need a common ground, and you always have to connect both wires of a power supply to whatever you want to power.

i've done a quick wire diagram, i didnt put the 4 fire from the stepper going to the L293D and the four wire from the L293D going to uno for more clarity purpose.

is my diagram correct if i want to power everything with a wall-wart (a 4 pack battery on the picture because i didnt found a wall-wart picture)

[kotnico]

can someone please answer my question about the wire diagram please

[wvmarle]

Do post a schematic of your intended setup. Those Fritzing diagrams may make nice art to hang on the wall, that's about all it's useful for.