simple breakout board

[linkintiger]

i was reading the web site

Putting the laser cutter together electronics edition!

and i was wonder why we need the whole breakout board when this guy connect stepper motor to parallel port by using uln2003 in a very simple way. Can this be done for cnc table?

[Jesse B]

Most breakout boards offer protection for your parallel port. Is there's a spike in voltage/current, you can potentially damage or destroy your parallel port. If this doesn't concern you, you can connect the drivers directly to the parallel port.

You could also just use a very basic breakout-board, like this: http://pminmo.com/db25/basicBOB.htm

[Bubba]

a breakout board can also provide the possibly necessary level shifting that may be needed between the parallel port (possibly 3.3V) and the most of the time required 5V for the drivers.
My preference is to use opto isolators between the computer and the device and some BOB include this feature. And as stated previously, the terminal strips make it easy to stick the wire in and screw it down.

[Al_The_Man]

There tends to be a certain paranoia about ensuring that commons are not connected together, yet if they are all bonded together properly at a central point and connected to Earth Ground, the chances of anything happening are slim.
I have been using this philosophy for many years with no problems.
As I have pointed out before, your computer MB has 99% chance of being directly connected or common to your (electrically) noisy Universal spindle motor or VFD, whether you are using 0pto isolation or not.
Al.