I would like to start a project of creating a simple robot. I want to do this by having everything powered by batteries. How would I go about powering the 3 servos and the arduino? Would I use one power supply for everything, or seperate them into 2 power supplies? Also what kind of batteries would I use? Thanks :)
I plan on using 3 http://www.sparkfun.com/commerce/product_info.php?products_id=9347
Well it really depends on the specific battery voltage you are planning on using, there are so many different choices, just stay away from standard 9vdc battery. ;)
Points to consider when designing your battery power supply.
Plan on 3 servos drawing peak 2+ amps worst case or so. Therefore the servos cannot utilize the Arduino on-board +5vdc as it's built in 5v regulator is current and heat dissipation limited.
Servo voltage ratings are normally 4.5-6vdc, so can be powered directly from four AA alkaline cells, nicads or nimh rechargeable, no regulator required.
If you use a higher voltage battery then any regulator added to supply +5vdc should be rated at 2 amps or more for an Arduino board and two servos.