sirphilip:
@polishdude20Thanks for the response. I did try connecting the transistor directly to the arduino 5V out. It is a pretty small DC motor, 1.5V if I remember correctly. I measured the current draw on the motor connected directly to a 9V battery and it was pretty high, about 650 mA if I remember correctly. The 2n2222a is rated to 600 mA, but I figured that would be enough to run the motor just a little slower. Is this logic wrong?
The ATMega itself was getting hot, not he voltage regulator. I am guessing this means it was drawing too much current through itself, which makes no sense to me.
I read through your thread, you found out you just needed to use MOSFETS? Maybe I will go buy some of those tomorrow.
yes but my problem was that the transistors where getting too hot and not the atmega itself. hmm. I also had a 1k resistor in series with the base of the transistor, try that. Also it would help if you posted some code maybe? The MOSFETs I use I found in an old UPS
(Uninterruptible power supply) and they are the IRFZ44V, I know how confused I was when I was trying to buy parts and didn't know which ones exactly s there's that name for you, I'm sure there's other equivalent ones that will work but there ya go.
Oh and that logic isn't wrong your right, at 9 volts the current averaged at around 650 mA so approximatly at 5 volts lets say the current would go down to around 350mA at 5v using ohms law so yeah that should be fine, BUT, you might find that the motors use maybe almost an amp when they spike right when they start from a full stop. Check the current through the motor again with 9v or 5v if you want, and this time, like crossroads told me in my post , measure the current while the motor is stopped with your fingers, then also check that spike in the current when the motor first starts from a stop. Because if it does that you may find that the transistor can't provide that high spike current to get the motor to even start.
Lastly, try and "help" the motor by spinning it with your fingers while you have the transistor providing current.