This page links to UNIPOLAR and BIPOLAR stepper motor driver pages. The drivers are designed for simple requirement applications and are made with parts that are available from a variety of sources.
Both of the stepper drivers are use a 74194 - Bidirectional Universal Shift Register from the 74LS or 74HC - TTL families of logic devices to produce the stepping function. A diagram at the bottom of this page shows the difference between the 74194 - UNIPOLAR and BIPOLAR stepping pattern generation.
These stepper drivers have only basic control functions: Forward, Reverse and Stop and Step rate adjustment. The calculated Step rate adjustment range of the drivers is 0.72 (1.39 sec) to 145 steps per second. (Lower and higher step rates are also possible.)
The only step angle for these drivers is the design step angle of the motor itself. 'Half-stepping' is not possible with either of the driver circuits.
NOTE: The UNIPOLAR and BIPOLAR stepper motor driver circuits on this web site use the same circuit board, the difference between the circuits is a jumper at the data inputs of the 74194 shift register that programs its outputs.
If the jumper is left out of the 74194 circuit its output will be for UNIPOLAR motors and if the jumper is put in the 74194 circuit its output will be for BIPOLAR motors.
The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.
If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.
Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.
16 September, 2012