Hello,
I'm sorta new to electronics (been messing around with Arduino for several years though) and I'm wondering if it would be a problem to tap into the USB cable that powers the Arduino so I can provide more power to my two servos instead of having to provide an entirely separate power supply for them. The max draw of the servos are 1A each. I would of course be using a USB power adapter that would be rated at ~3A (1A * 2 for the servos [2A] + <=1A for the Arduino depending on the specific Arduino I decide to use for production purposes).
I've attached an image of what I'm proposing. Will that work properly and not affect the health of either the servos or Arduino (assuming that the servos don't stall, etc)?
P.S. I've omitted the servo signal wires from the sketch since the question is strictly about powering them, not controlling them.
ARGHH !
Please dont tap into the USB supply as they are generally rated at 500 mA and the computer that is supplying that power will likely have a major fit if you try suck too much amperage from it and running servos, motors, etc is likely to cause a whole raft of other issues.
Same with a powered hub or similar dont tap into it as you could also introduce power spikes from servos and motors and fry the hub without extra precautions.
As is always recommended a seperate PSU with more current that is needed preferably and with just a common ground back to the Arduino.
If you have a 5V power supply with a suitable current rating which just happens to use a USB connector for its output then you should be o.k. You also need to be a bit careful what cables you use because some have very thin wires and are only rated for 1A maximum.
It is still preferable to have a separate power supply for electrically noisy things like servos and motors but provided the current rating is adequate you should get away with it. Of course if you ever plug that USB cable (just for a quick test maybe!) into a PC you may find yourself in a whole world of trouble.
Steve
