Hi I am pretty new to Arduino.
I have a little concern. For my project, I need to use a fairly big motor. The battery for the motor is a 9.6V, 1.2A rechargeable NiMH. I power the motor through an external rail on the breadboard. The negative of the battery share the GND with the Arduino Mega. When I connect battery to the rail, without any power to the Arduino itself, the Arduino turns on, (theYELLOW led comes on.) Is this normal? would the 9V battery kill the Arduino? So far it hasn't yet, but I am concern that it might. And I am also wonder, shouldn't the external battery powers only the motor and not the Arduino? Am I doing something wrong? Is there a way to completely isolate the external battery from the Arduino? Thanks in advance.