I don't think it's possible, but I want to drive my 433 MHz transmitter (FS21000A) from a 12V 'supply', to get more power (and thus more range).
However, I don't have an external power supply. I can add an adapter (12V/1A) to my Arduino with the barrel input, but I wonder where to get 12V from? I only see 5V or 3.3V outputs.
And as far as I know all GPIO output 5V ... so how can I get 12V (or maybe a bit less but more than 5V) out of an Arduino? (and what safety measurements I should take to not ruin my Arduino?)