!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?)

My first Drone
Arduino nano + L293D + hc-06
Objective: learn how to use Bluetooth with Arduino.
V 0.1 (no direction, commands by serial terminal).

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

Hey guys.
Arduino + Bluetooth + L293D + car Chacis and 4 DC motors.

Finaly finished my second bot/Drone.
Actually finished it yesterday but had lots of problems with hardware bugs (learned so fucking much in a day).
Tought I fucked two unos with bad soldering... No they are fine, just won't turn on in the circuit that was already working (was fine running the code).
Redone everything from scratch with a arduino uno, it's perfect now.

Funniest part is how I got my hands on a 50€ car kit for almost free... So some Chinese store sended this kit instead of some cheap stuff. Saved another arduino with the chip rack (that one that you can trade the atmega chip), I'll save it to program single chips. Plus a h bridge and lot lot more cool stuff.
Used only the Chacis.
Next: esp8266 and camera... And maby a gun? Would be cool

What's the most efficient motor driver for a small DC motor that I want to run off a 5V source for aurdino?

I previously had a L293D and it was inefficient as fuck, it got so hot that almost burnt my finger, (ran it from a 12V supply) and it dropped a good 2 volts from power supply to motor.

Is there a good enough off the shelf driver or do I have to make a H-bridge myself using MOFSETs?