I was talking to a tech savvy friend who does a lot of robot building, got onto the discussion of how I am looking for a robust driver for a stepper motor. He said you can use Basic Stamp (available frm Parallax) to control steppers. THis what he uses for robots. THere was a kit he mentioned, for 30 bucks a piece that will drive them. ANd i guess they are not at all harmed if you disconnect the motor with power on.
Can somebody elaborate on this? This sounds like my kind of driver
There are quite a few different drivers. Parallax has some to go with the stamp. Jameco's Robot Store has one or two under the motor control section. Also take a peek at Robot Store HK. Jeffery Kerr offers the Pic-Step chip that can be controllerd by RS-232, and hence a stamp.
If you want to try something different, as in driving a pair of steppers from your PC's USB port vs. a basic Stamp, look at UsbMicro's U401 or U421 interfaces. They say "The U401 can be operated as a two channel stepper motor controller. The U401 can interface to various types of stepper motor driver circuits. The stepper sequence can be "Wave", "Full", or "Half" with control over direction and speed."
The speed control is a single byte, so you have 256 discrete speeds in each direction. Output is NOT step and direction, but one output per coil (four outputs per motor). You can interface to unipolar or bipolar with the right "in between" hardware.
Go to Barnes & Noble or Borders and look for an issue of Servo magazine-their advertisers index can point you to more sources of parts.
I doubt that a basic stamp would be fast enough to work as a chopper drive unless the chopping is done with external hardware. Last year I used an AVR (much faster than a Stamp) and it wasn't fast enough to run without a lot of jitter.
A stamp based driver will probably need giant resistors for current limiting and the performance will still be poor compared to a microstepping chopper.