motor controllers and their operation

[dellagd]

Hey guys, I wana convert a servo powered bot to motors for speed. What would be the least expensive motor controller and would the motors found at radioshack be suffecient? the robot is the one I am entering in the contest.

[Webbot]

You need to say how much current your motors need.
The Toshiba TB6612FNG is a nice cheap $9 - $10, and small, dual motor driver if you are in the 1Amp continuous, 3 Amp peak, kinda range.
Available from SparkFun and others.

So choose your motors - based on robot weight, speed/torque required - using Admins calculators.
Then find a controller that can drive the motors.

[dellagd]

ok ok, I think I got it
would 2 of these work well for a reasionalbly fast robot?
http://www.trossenrobotics.com/store/p/4917-GM8-Gear-Motor-143-1-Inline-Offset-3-6V.aspx
from my calculations yes.

can someone tell me how I would use that motor controller webbot listed? the shematics are out of focus and I pretty sure i wouldn't be able to anyway

[Webbot]

Will your motors work? Are they fast enough?

Well only you know - as you've not given any figures. 

Well if you go with that motor then the stall current at 6v is 660ma which is easily achievable with the TB6612FNG I listed. See http://www.sparkfun.com/commerce/product_info.php?products_id=8905.
It can supply 1Amp per motor continuous.

And if you wanna know how to drive them --- WebbotLib supports that controller