larryd:
Example:
I have made several clocks using a Pro Mini an RTC and neopixels.They function by themselves and do not need to be connected to a PC to function.
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Thank you. So you just plug in an external power supply and the Arduino starts to work and somewhere, I guess a LED display gives me the info.
In my case I have to options. No display at all just by blinking LED I am signalizing what my hardware is doing and this when I connect it o a battery (that would be a stand alone) and if I plug in a USB cable then I want to have a User Interface where the User can interact with my hardware.
regards Rainer