So I've got a pretty basic servo project in the making. I'm quite certain the arduino 5V cannot give me enough current for what the servo needs to do, so I want to try 4 AA batteries in series to see if they can give me enough juice.
So the schematic and layout is very straight forward:
The first time I hit a pushbutton, the sevo goes from 0 - 180 degrees. The next button press makes it go back from 180 - 0. It all works flawlessly when using the 5V from the Arduino. But when I hook up the battery pack to the servo (6.4 V) then the servo doesn't move AT ALL??
As soon as I switch the 5V Arduino power source back, the servo does what it should.
Could it be simply that the servo can't be run with 6.4V?
There must be a complete circuit (circle) for the servo signal. So when the signal goes from the Arduino output pin it must have a way to return to the Arduino to make the circuit. The ground is the return.
Arrg, the servo is still stalling under the load. I read about 550 mA of current draw. The stall current for the SG90 is around 650 mA. Do we think its the batteries still not delivering the required current or do I need to look for a stronger servo?
4xAA alkaline, if fresh, can deliver about 2 Amperes. But if the servo is stalling under load, it will burn out very quickly. You definitely need a bigger one.
The MG996R has a stall current of about 2.5 A, but for just one of those, you still might get away with a 4xAA alkaline battery pack. 5xNiMH AA would be much better, though.
