Hi,
I've just seen that Sparkfun.com sells some nice Stepper Motors and also Motor drivers for those:
Motor: http://www.sparkfun.com/commerce/product_info.php?products_id=9238
Driver: EasyDriver - Stepper Motor Driver - ROB-12779 - SparkFun Electronics
After googling some, I found that there are nice tutorials showing how to run a stepper motor with Arduino:
http://lusorobotica.com/index.php/topic,106.0.html
I've wanted to do a project with these motors for a while now. The only question that I couldnt answer is: Do they also need an encoder to ensure the right position of the motor? Or does the stepper motor move exactly the steps as told to the driver, whatever torque is on the motor?
The Driver datasheet says:
By simply inputting one pulse on the STEP input the motor will take one step (full, half, quarter, or eighth depending on two logic inputs).
But I dont quite understand if the motor does that anyway, like ensures to do that, even if it was blocked - would it try to move the step anyway until it was moved?
My idea is to create a table with a XY carriage to shape thin lumber and maybe aluminium. I'd build in a reduction gear to raise the step-resolution of the motor and also the torque. But would I need like a rotational counter to check if the stepper motor does exactly the amount of rotations whch I tell to the driver?
Thanks!