problem with Vin pin, is it necessary?
Arduino ASCOM Rotator multiple designs
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Hi, I'm building the rotator, everything is great!
But I have a question about the Vin pin. Why is it connected? I've tried not connecting it, and it works perfectly with USB power.
However, if I connect Vin, if I connect 12V first and then the USB, it doesn't work. The Arduino shuts down and doesn't connect to the PC. I have to unplug the 12V and reconnect them. That is, I have to connect the USB first and then the 12V. Is this correct? Why does this happen?
That's why I'm asking if it's necessary, because if I remove the Vin, the connection order problem disappears.
Thank you very much!
Vin is the means to power a 12V NEMA stepper motor.
There is a limit on how much current the board can get using USB. For older USB types then the limit is low. But USB3 and C provide a lot more current and when used with ULN2003-28BYJ-49 motors then 12V connected to board may not be required.
The messup re 12V and when to turn on has more to do with the USB connection and Arduino chip components, and not the project. As you have found, there is a solution that you discovered.
If you have no need for the 12v then just use your usb connection.
Regards