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You'll need a separate 5 or 6V supply for the servo and common only
the GND terminal with the Arduino. The Servo library will drive a servo from
any pin.
When you say 3.3V and 5V, you'll need to say what you want to connect to what -
typically you'll need to level shift (search here for "level-shifter")
Yes you can use 3.3V and 5V simultaneously, its only connecting things together
where it matters!
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A servo on the 5V pin would make the Arduino constantly reset. But using the 5V and 3.3V pins at the same time is fine, as long as you don't draw more than 50mA from the 3.3V pin and 500mA from the 5V.
3.3V regulator should be good for 150mA.
The main page says 50mA, but I'll bet that is a carryover from the FTDI days when the 3.3V line of the FTDI chip was used.
oren_partesana:
Why would I need a separate supply for the servo? This guy seemed to make it work: https://www.youtube.com/watch?v=qciLa_Wo8oM
You never power a motor and logic chips from the same supply, it is
asking for trouble. ~90% of all issues relating to servos on these forums are
from people who've tried it and suffered issues. Motors put out big spikes and
dropouts onto the supply, logic chips require guaranteed 5V +/- 0.25V.
Besides the servo will need at least 1A, possibly 2A supply, which the Arduino
cannot provide at all.
Also, what would happen if I were to connect the bluetooth module power to the 3.3V pin and the servo to the 5V pin simultaneously?