Electrical – Control 220V stepper motor with arduino

There are two kinds of stepper motors: unipolar and bipolar. Unipolar steppers have six wires coming off of them and bipolar ones have four wires. To control a unipolar stepper, you need to use a chip called a darlington array. To control a bipolar stepper you use an h-bridge.

I've never worked with unipolar steppers, but I can explain how to use bipolar ones. The first thing you need to do is find which wires are paired. Use a multimeter and one-by-once connect the meter to every possible pair of wires while measuring the resistance. On two of the pairings you'll find non-infinite amounts of resistance. These are the connected pairs. Attach each of these to the different halves of your h-bridge.

Once you've got your control circuit wired up (whether it be the h-bridge for the bipolar stepper or the darlington array for the unipolar), you use the Arduino Stepper Library to control it

I've got a write-up of a recent project I did with steppers Since I'm only allowed to post one link here, refer there for links to many of the things I mentioned here.

Tom Igoe has a great write-up about steppers on his site.

This is really a termios (and perhaps by association serial) question - there really isn't any relevance to stepper motors other than it being a problem you encountered in the course of talking to a board that happens to drive one.

Most likely the program is adjusting the termios settings for the terminal in addition to for the serial port. It's probably setting a variety of things, including some lower-to-uppercase translation such as the OLCUC flag or something along those lines.

One solution may be to use tcgetattr to grab a 'backup copy' of the original termios settings into a struct and then use tcsetattr to restore them on exit.

You may be able to recover more ordinary terminal settings after the exit of the program in its current form with stty - for example 'stty sane'