I'm new to arduino but currently brainstorming about building a robot arm controlled completely by the arduino mega 2560. After some research, I found that stepper motors are used in many pick and place robots and other precision movement machines. Since the task my robot needs to perform is pre-determined (the position of all objects need to be picked and placed are known), I thought I should use steppers since the degree of rotation can be controlled by a motor driver and an arduino.
So I found this Quadstepper board from SparkFun that can control up to 4 stepper motors, which is nice since most motor shield can only drive up to 2 and I need to have at least 3 steppers.
Could you guys please tell me if this board is desirable for this project? And if it is, what kind of stepper motor should I get? The arm is built with VEX metal pieces and it's kinda heavy since I have to apply an idle voltage to the VEX motors (before I decide to go stepper) to keep the arm from falling. So, according to my description of the arm, what kind of stepper should I get so that it would have enough torque to turn the arm? Would it affect the precision of the stepper if the arm is that heavy?
This is what I have in mind so far, please give your precious suggestions and answers! Thank you in advance!