I just want to ask about this, it really bugs me.
how an arduino able to give signal in a pin without a ground?
I have tried to remove the ground wire from external battery to arduino and the motor still works.
the arduino is powered by my pc's usb.
Please see above image.
then this code digitalWrite(STEPPER_PIN_1, HIGH); digitalWrite(STEPPER_PIN_2, LOW); digitalWrite(STEPPER_PIN_3, LOW); digitalWrite(STEPPER_PIN_4, LOW);
The STEPPER_PIN_1 is set to high and all remaining pin are low.
how the ULN2003 able to detect that the pin is HIGH or LOW.
What im trying to say is just like a battery you need a positive and negative to have a current flow.
Please let me know if it is ambigous.