Basically I would like to power a Seeeduino Xiao (basically an Arduino board that accepts 3.3V) and a 28BYJ-48 stepper motor via a ULN2003 Board (which accepts 5V). I was thinking of using a single 9V AC-DC adapter to power both and just was wondering how I could go about splitting that voltage? I was looking into voltage regulators (but it seems that it basically just steps down your voltage). Also the more compact the solution the better. I Basically just want to have one plug for my Arduino project and was wondering what would be the best way to go about it, Thanks!
$\begingroup$ Two regulators, one for each voltage and make sure the one for the motor can do the power and current needed. $\endgroup$– Solar MikeJun 5, 2022 at 18:33
$\begingroup$ Xiao has onboard regulator from 5V to 3.3V. Challenge might be in having to turn your 3.3V outputs into 5V that the driver will reliably recognize $\endgroup$– AbelJun 5, 2022 at 20:20
If the things need the same voltage then just wire them in parallel.
If they don't, then add some regulator or converter so they do.
Don't even think about wiring two unrelated circuits in series unless you really know what you're doing.
Based on ULN2003A datasheet, its on-state input voltage does not exceed 3V. So, you do not need 5V regulator at all. ULN's inputs go to MCU outputs, ULN's collectors (outputs) go to motor coils ends, and motor coils' middle wires go to 9V (5-12V possible) source.