Does the method of powering arduino matters?
When it comes to electronics I am pretty green, so please forgive me.
Today I was reading an instructable dealing with Shift Register ([url]http://www.instructables.com/id/The-74HC164-Shift-Register-and-your-Arduino/?ALLSTEPS[/url] ), and came upon a problem. I had problems shifting out different patterns of LEDs. At first I though I had a defective chip. After changing the chip the problem persisted. Next I noticed that if I reset the Arduino a couple of times I would get a correct pattern displayed. I tought that maybe it might be something to do with my power source. I was running my Arduino from the USB. I tried connecting Arduino via my 5v power supply (http://www.sparkfun.com/tutorials/57), and everything started to run smoothly.
So the question is. Is the USB power not clean? and that is why I wasnt able to displayed a correct patter or was it something else?
Would it be possible to solve this with some other method?
Any links on the subject matter would be greatly appreciated.