I am in the process of developing a linear bipolar stepper motor driver. It is similar in concept to the Linistepper with the main difference being that it is designed for bipolar stepper motors rather than unipolar stepper motors. The benefits of this kind of driver are:
-runs smoothly
-runs quietly
-less heat generated in motor
The drawbacks are:
-relatively complex circuit
-lots of heat dissipated in driver circuit (which also limits drive voltage)
The main reason I started this project is because when driving my 3D printer steppers at moderate speeds, the steppers would get hot and eventually start skipping due to the decreased torque. This happened even when driving the stepper quite a bit below their rated current. So after doing a bunch of research, it seemed that a linear stepper would fit my needs best. Unfortunately there doesn't seem to be many drivers like this on the market, so I decided to build my own.
So far I have built a functional prototype and it works great. The current waveform through the motor is a very nice sine wave. At this stage I am updating the circuit (mostly to reduce physical size) and I figured this would be a good time to get some input on whether or not there is much interest in this, and if so, what features people would like to see.
Right now the peak output current is adjustable from 1-5 amps with a potentiometer. It is set up with 16th microstepping and there are currently no external microstepping mode adjustments. The control inputs are step, direction and enable and can handle logic from 1 to 20V. Power input is 5-24VDC.
If anyone has any questions, comments or ideas, please let me know. Thanks.
