Hi all, I've used Arduino in the past to do some fun solid state stuff, but I've never made anything MOVE. I went out and bought parts that ended up not working together (got an H-bridge for a unipolar motor), so I'm coming to you all on advice before I spend more money. I'm also open to any other general advice on motor sizing, power supplies, etc. as I'm being very honest when I say I know little. I'm open to buying different equipment if really necessary, I'll always have other projects.
Project: Motorize a hand-crank apple peeler (this one has a potato... weirdos)
(You can see something like this in action at the following YouTube video, if it helps you visualize.)
This specific motor assembly is intended to drive the central screw-shaft in pic above. My working theory is to mate the motor directly to the back of the screw (where the handle connects in the above picture) and put the motor assembly on a sliding rail so it cannot rotate but travels back and forth with the screw as it moves. I've used these before, and not too much force is required to push an apple through the peeler, especially when the cutting blade assembly is kept well.
Motor: A stepper motor was desired for low cost and high holding torque so that an operator can load/unload apples at the start and end of each peeling cycle. I currently have the following motor:
Type : 6-wire unipolar
Rated Voltage : DC 12-40V
Rated Current : 1.2A
Rated Speed : 1000RPM
Rated Torque : 3.5Kg.cm
(Amazon page: http://www.amazon.com/gp/product/B008ICMY2E/ref=oh_details_o00_s00_i00
Power supply: Just a standard wall-outlet transformer.
Rated voltage: 12V DC
Rated amperage: 1500mA
I've done my research and realized that I need something like a Darlington transistor array to drive the unipolar motor. The chip that comes up constantly in my searches is the U2003, but my reading of the spec sheet says that it only supports 500mA per channel, and according to the motor I have above I believe I need something that supports at least 1200mA per channel. However, I'm unable to find any array that supports that kind of current.
(U2003 specs: http://rocky.digikey.com/WebLib/Texas%20Instruments/Web%20data/ULN2001A-4A,ULQ2003A-4A.pdf
How does the project sound so far? Can anyone point me to a driver that handles the current I'm looking for? Will I have a problem driving the motor at 12V when the operating range is 12-40V? Have I said anything really stupid?
Thanks for your help!