neil, I have been down the same path. Building your own controller / driver is fun, but also a lot of work. I have built a 3 axis desktop miller using a purchased driver that runs off a PC parallel port, using GCode shareware. It is extremely functional and was easy to integrate. See www.stepperworld.com for the driver. I use the FET -3 Product. They have a link to the shareware, Kam3. It is amazing how inexpensively this can be done. The fet-3 requires unipolar steppers, which means that the coil current is driven one way, not two way as in bipolar. Good luck, George Sacco ----- Original Message ----- From: "Picdude" To: Sent: Wednesday, March 24, 2004 2:07 AM Subject: [EE:] CNC stepper-motor controller? > I've been pondering the purchase of a CNC lathe/mill, but for cost reasons I'm > going to do this incrementally ... pick up the basic machine first, then add > on stepper motors and CNC capability later. But I'm researching first... > > Seems like there are multiple vendors that make CNC controllers and the best > part is that they're all compatible (work with the same software, interface > thru the parallel port, and control the same types of motors). > > I'm thinking of making my own controller instead of spending $500-$800 for a > ready-made unit, but I'm evaluating if this can save me any money (I really > expect it would definitely be worth my time). > > I found a bunch of general stepper-motor controller circuits thru google, and > it seems that the L298 drivers are popular for this size stepper motors (Nema > 23, generally 100-150 oz-in units). Not sure if the motors are run unipolar > or bipolar (I'm still figuring out what exactly that means) though. > > I'd like to control this with a PIC. The PIC and par-port side of things > should be easy, once I figure out what this interface protocol standard is. > > Any of you know what this parallel-port "standard" protocol is? Got any good > circuits that do this already, to save me re-inventing the wheel? > > Thanks, > -Neil. > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.