Okay--very new at this. Can someone help explain why this isn't working?
I set digital i/0 13 to high. I know it has 5v because the built in LED on the board is on, and when I run an LED from pin 13 to GND, it goes on, too.
But when I run a small DC motor from pin 13 to GND it does not run! Wait--I know what you're going to say! "You need an H-bridge, or a transistor". But the motor is TINY (don't know actual voltage), and when I run it directly from the 5v pin (not I/O pin 13) it runs.
Pager motors expect 1.3 V typically. Giving it 5 V might damage it. Even a pager motor needs 70mA~120mA of current. Trying to supply that much current from an Arduino pin might damage the controller.
"Wait--I know what you're going to say!" Then why did you do it?
It is a mistake to assume that just because a motor is tiny, it has a smiilarly small current draw. Often (at least apparently) one of the things that happens to make a motor small is that there is not as much room for the large amount of wire inside that would lead to smaller current draw, and since they're aimed at only running occasionally (to vibrate your phone when it gets a call, say), a higher current consumption is OK.