I am looking at producing a 3 motor driver for 3 stepper motors.
So far I have found the pololu units are the cheapest I have found so far. Problem is they are bipolar and apparently these require more complicated circuitry with an H bridge thing. I have been looking at the pololu driver boards (A4983) it says it requires 8 - 35v but the motor is rated for 3.9v
Also can I get one with the voltage regulator and two without and use the same logic voltage?
I assume with proper stepper drivers the I/O pins of parallel ports enable the direction and step pins on the driver boards.
Bipolar stepper motors have two coils that you must energize in both directions, so you need two H-bridges (one per coil). However, the A4983 has everything built in, and it will limit the current to what you set it to, so the motor voltage being lower than your driver supply won’t matter, and you don’t have to worry too much about the details of the H-bridges. Yes, you can use one unit with regulators and two without together. Controlling the drivers from a parallel port should be doable, but that’s up to you. (I’m assuming you’re talking about a PC parallel port.) You have to pulse the step pin for each step you want a motor to take, so you’ll want to be generating thousands of pulses per second, and I’m not sure how practical that will be on a parallel port.
It is for a small balsa wood cnc router, I have a program called Kcam which you configure a parallel pin for step and direction for all the axis and it does it for you.
Would I need some kind of +12v - -12v to TTL level thing for the parallel port to the driver boards like RS232s do?
You don’t need a level converter. You might want to put in some in-line resistors in case the voltage levels vary a bit. In general, you should make sure you know what you’re doing before connecting things to your computer so you don’t destroy it.
Thanks for the help! Two of the axis will have leadscrews so I won’t need very much holding torque for them but one will be directly moving the material in and out which will probably need some torque.
