What is the recommend power scheme for an Arduino, dc and servo motors? The dc motor supply ranges from 3.5 to 7.5 volts. The power for the servo ranges from 5 to 6 volts. I'm using a 9.6 volt NiMH pack for the robot. I'm considering to use a l317 adjustable voltage regulator for the dc motor supply voltage and 9.6 for the Arduino. Could the servo be powered from the regulated 5 volts off of the Arduino ?
It depends on the number of servos you want to use. Anything more than one is not recommended to run off of the Arduino's 5v rail. You'd need a shield like this one to properly run multiple servos, as you could connect a separate power source to the shield to avoid putting stress on the Arduino's power regulator. The shield could also run the motors you'd use in your project! The only other recommendation I have is to consider investing in a Lithium Polymer battery, as I've found those are generally better suited for projects like this.