i want to use the teensy board to control 12 led's.
for the led's i need 5V so i have to use 4 AA batteries (1.2V) to power them.

the teensy itself should be powered by the 4 batteries too. what do i have to do? i can only find some notes about teensy2 + batteries here: http://www.pjrc.com/teensy/external_power.html

what i also want to achieve: when the teensy is plugged in via USB i want to recharge the 4 batteries. how can i do that?

thanks in advance!