Can I use the digital (or analog) pins to switch the 3.3V output?
I am worried that the digital pins go HIGH to 5V
and how will that interact with the 3.3V?
And can the pins switch the 3.3V?
Can I switch the 3.3V output from the Uno board through the digital pins 0 to 13 (and analog pins 14 to 19)?
As I read it the HIGH on these pins (0 to 19) is 5V?
Maybe I should just wait for the 220 ohm resistors and use the 0 to 19 pins normally?
Are you saying I shouldn't wire LEDs on a 3.3V line without a resistor?
I want to blink 200 LEDs (one or two MAX)
I am under the impression a resistor (220ohm) is only needed when you connect 5V to an LED?
R = voltage / current = (3.3 - 2) / 0.015 = 1.3 / 0.015 = 86 ohms (rounded up to 100 ohms as the next standard value if you are using 10% tolerance)