I've got an Arduino Mega ADK and the Adafruit motor shield.
I have this board:http://www.ladyada.net/make/mshield/
and this arduino:http://arduino.cc/en/Main/ArduinoBoardADK
It seems that motors are being powered by the arduino even though I have turned off the external power supply, as they still attempt to move. I'm using code from here:http://www.instructables.com/id/Intro-a ... oull-need/
For this first test, I am powering the arduino off of USB. I notice that the LED is lit as soon as USB is powering the arduino, or when I apply voltage from the external power supply (the roomba's battery to a voltage converter). I have the power jumper hanging on one of the pins, so it's disconnected and the motors should be drawing power from only the external power, right?
I bought the motor controller on amazon, and it came assembled. I am testing it out for the first time.
The motors sing a little, and it kinda sounds like one of them might not be moving. The arm worked fine even after I made a mount and whatnot for it.
The power supply is 5V 2A. I didn't realize I'd need a higher voltage b/c of the voltage drop on the H bridges to get 5V to the motors until i read a post here. I don't know if I have a supply in that range, but I'll look when I get home. Is 3.8V too close to the lower limit for this stuff?