We have an LED strip connected to output 6 and is powered by the Uno board itself. Shouldn't be drawing too much current, only have 10 elements on the LED strip. While this LED strip is connected to the Uno, I noticed that the regulator is getting very hot.
One thing we haven't done yet is to power the LED strips from an external source, which will be necessary since there will be many strips. At the moment, the students are simply trying to debug their program with the small strip.