Hello Everyone,
Right now I have a setup in which I have 2 9 volt batteries, an arduino uno r3, 2 28BYJ48 stepper motors, and 2 ULN2003 Motor Drivers
I had a question as to which pins I could use for the IN1, IN2, IN3, and IN4 on the motor drivers. I have two of the motor drivers, so I need 8 IO pin sockets on the ardiuino to attach them to, but I don't really know which ones.
Just the pin numbers that will work would be appreciated
Edit: I now know that I can use pins 9, 10, 11, and 12, but I need 4 more that I can use
An Uno has 20 I/O pins (0-19).
Pin 0 and 1 should be avoided, because they are already use by the USB<>Serial chip.
Pin 13 can do funny things at bootup, so avoid if you can.
Pins A0-A5 on an Uno (14-19) are just common digital pins (with analogue read capability).
pinMode(A0, OUTPUT);
and
digitalWrite(A0, HIGH); will work
so does
pinMode(14, OUTPUT);
and
digitalWrite(14, HIGH); // Uno specific
I use pins 4, 5, 6, 7 and 8, 9 ,10, 11, the " ~ " indicates a PWM capable pin, 3, 5, 6, 9, 10, 11. There are 2 versions of 28BYJ-48, 5 volt and 12 volt, 9 volts may overheat a 5V model, but if you are using PP3 "transistor" batteries, they probably won't last long enough to hurt anything, you should have a proper 5V supply, like an AC adapter or "wall wart" or "plug pack".
If you mean the PP3 style 9v batteries then they are next to useless as they are not designed to produce enough current.
And you have not said how you plan to power the stepper motors. They usually need 5v but you should NOT draw that power from the Arduino 5v pin. Motors are likely to overload the Arduino 5v pin and cause erratic Arduino behaviour and the Arduino 5v regulator might be damaged.