Just keep in mind - "Vin" and the "barrel jack" are essentially useless. If you are using them, you are asking for trouble!
Connect your 5 V to the "5V" pin (that is after all, what it is for!) except when connecting to the PC via USB. 
Just keep in mind - "Vin" and the "barrel jack" are essentially useless. If you are using them, you are asking for trouble!
Connect your 5 V to the "5V" pin (that is after all, what it is for!) except when connecting to the PC via USB.