I use an external 5v supply to power L293D and a small bipolar stepper motor (5v) plugged on arduino Fio (3.3v).
It work fine as i expected with “stepper one revolution” sketch exemple. So the problem is, when i disconnect the external power supply, the motor continues to rotate powered by the arduino board and i noticed that the L293D is heating fastly.
Any suggestions please.
Image link to my wiring circuit: