I was originally powering the board off of a 9V battery, but it didn't last the night and all that was connected at the time was the Arduino and an LCD. Now moving on to add the servo, connecting it causes the board to brown out. It restarts sporadically and the LEDs fade. This happens with both the 9V and USB power.
I pulled up an old AC adapter that I had lying around, and it's rated at 12V/700mA. First of all, is this too much voltage for the Arduino? It runs the board fine, but I'm hesitant to leave it running for prolonged periods of time just in case. The voltage regulator feels a little warmer than usual.
Nonetheless, even with this power supply, the brownout issue persists as I connect the servo. Now, this makes sense to me, given that the Arduino regulates the voltage down to 5V and this motor is clearly expecting more.
So I was thinking about splitting the power supply before it reaches the Arduino. I just don't know how to do this successfully. Do I need a voltage regulator/associated capacitors before the motor? How do I "ensure" that the Arduino gets its share even when the servo turns on?
If you search the forum, you will find others asking exactly the same.
What you need to do is a separate power supply for the servo, so the arduino doesn't have to pull that too. The warmer voltage regulator is also because of the servo, and the extra (and since it is still shutting off) and too much current drawn from it.
So make a separate voltage regulator for the servo, connect both minus to each other, and connect only signal from the arduino to the servo.
Thanks for the reply! I had searched before posting, and came to that conclusion through searching, but the only question remaining is whether the other voltage regulator should be supplied by a different power source or not. What will ensure that the motor doesn't still pull too much power? The voltage regulators ensure it won't be too much going to the Arduino or servo, but not that there's enough, right? And is 12V/700mA enough or too much if I'm splitting it?
What will ensure that the motor doesn't still pull too much power?
If you give the motor the voltage it is rated at it will pull the current it requires. If you power supply has enough current capability it can supply both the motors (directly) and the arduino (through the regulator). In general you can't have too much current from a power supply, it is only what it can supply not what it will supply.
Cool, thanks. Last question, I promise: is it true that the regulator is supposed to be passed ~7V to ensure a clean signal? Thus, if the motor requires 6V and I'm splitting 12V, is that "too tight", or is it fine since the AC/DC wall-wart already gives us a pretty solid power supply?
Splitting 12V? You can't split voltage, but you can adjust it down by using a voltage regulator.
But you can add a million voltage regulators to the same voltage, and they will then all share the same. The problem is only if the supply can give enough current to drive all of them.
It is recommended to stay between 7 and 12V, because the voltage regulator then got enough to make a stable output.
But it might be possible for it to run in lower too. I am currently testing mine with a wifi shield and a servo, running it on only stabilized 5V through the external power input, and it works just fine too.
