+ Four speed by one button;
+ direction control by two buttons.
This circuit controls unipolar stepping motor with four windings. They are connected through the drivers instead of bulbs. With every turn of the transformer carcass (either manually or via a motor) the wire feeder is shifted by the amount of its diameter. Switching the stepper motor speed changes the flow step. For example the value may be: 1.2; 0.6; 0.3; 0.15 mm.
The left-most button sets the speed that is displayed by a flashing blue LED. The second and third buttons change the direction of movement of the carriage.
