!rant
Four hours of work.
You think you write spaghetti code? I write spaghetti wires.
H-Bridge dual motor tester for stepper motors.
Speed is controled by pot.
H-bride are L293D.
My third board, and the first that won't go to the trash.

Question. With the baterry off the motor continues spinning with the 5v from arduino.
My question is, is the L293D suposed to do that? Or do I have a short circuit somewhere that is giving power to the motor? Meaning it can burn the arduino.
Runs a 12v stepper from a CD-Rom driver perfectly at 5v from the arduino and actually starts to act strange when I turn the 12v on. (maby the circuit it's adding 12v + 5v?)

3 hours making this beautiful circuit to test stepper motors.
Arduino nano + L293D + pot
Fucking bitch has a short circuit somewhere and can't find it out...
Made the same project in a breadboard in 15 minutes and it's working.
Fuck hardware bugs.
Cutted in the middle of all connections, took out excess solder... Nothing.
Fuck it, moving to the next ideia

Recently bought an Adafruit Industries board which controls stepper motors over i2c. It has a Phython library, but my code is in C++. Decided to convert the Python code to C++ to get started quickly. Behold the magic line that made everything work:

std::this_thread::sleep_for(std::chrono::milliseconds(10));

I can't believe Python's ridiculous performance is being harnessed to let the field generated by electromagnets in a stepper motor to grow to sufficient proportions to affect movement. Without the said sleep(), the stepper motor just vibrates with my C++ code. Not sure if the library was created with Python's performance in mind, or they simply didn't think about back EMF in electromagnets...