Stepper Motors

In the beginners section we learned about the basics of what stepper motors can do. This section will look at the Robologic stepper motor and discover how to program it.

The Robologic stepper motor is a four phase unipolar motor with a step angle of 7.5 degrees. It has 6 wires coming from it in 2 sets of 3. Each set is connected to its own winding. The central pin is the ground pin, and the 2 pins to the left (pin 1) and right (pin 2) are connected to each winding. The arrangement is the same on the second set of pins.

The Robocore can control up to 2 stepper motors using its standard dc motor connections. To follow this example attach pin 1 and 2 to the Robocore's first motor output and pins 3 and 4 to the second motor output. The two ground pins can be connected together and attached to the batteries negative terminal.

The following sequence steps the motor through one complete cycle.

Step	Pin1	Pin2	Pin3	Pin4
1	ON	OFF	ON	OFF
2	ON	OFF	OFF	ON
3	OFF	ON	OFF	ON
4	OFF	ON	ON	OFF
1	ON	OFF	ON	OFF

The motor can be made to rotate anticlockwise by stepping backwards through the sequence. I.E. Step 4,3,2,1,4,3 etc