Stepper Driver Testing

Earlier this week I mounted the EZ Driver in the case:

The parallel cable can be seen there running out the back of the case. This is for testing purposes and will be replaced by the Arduino. I'll probably put the Arduino in the left rear where the transformer was supposed to go. Then I wired up the stepper motors:

I'm not the best at soldering, but I actually found the PCB soldering to be easier than the wires for the steppers. The problem is holding the wires together while you solder. And remembering to put the heat shrink tubing on first. There are 6 wires (with 2 doubled). Even when I put all the heat shrink tubes on first, one or more would fall off and I wouldn't notice. Then I'd have to reheat the wires and pull them apart. Or I'd heat them up too much and the tube would fuse where it was - not covering the joint. The first of the 6 wires was easy, but after that, the tension and rigidity of the wires made it hard to keep them in place so my hands were free to work the iron and the solder. You can see my "helping hands" unit on the right. I didn't bother with that, I got faster as I went and developed a workable technique. I found it difficult to get the outer heat shrink tube to stay up against the motor while shrinking it. It's pretty good, though. Here's everything lined up, ready for testing:

I will be building the "computer" from an Arduino microcontroller. It's going to take me some time to develop it and I just gotta know if the thing works. I don't want to work on the Arduino part and have it not work and me not know which part is failing. So I dragged my backup PC down to my shop:

Yup, that's Darth Vader in the background. Seeing this behemoth in my shop is, well, not pleasing. I could fit my mill and controller on the same table the computer is on. But it's a PC with a parallel port and it runs software I can use to test it. I downloaded a copy of EMC2 on Ubuntu Linux. It has a "live CD" mode meaning I can run it from the CD without installing it. I was not able to get EMC2 to run, it kept crashing after loading the config file. 

I was able to get the configuration utility to run and it had a test mode you could jog the axes with and that was good enough. I looked things over one last time and turned on the driver. There was a loud thunk as the motors energized, a bit disconcerting. But I jogged all 3 axes and it worked great! 

There's a lot that I had to do right to get this far. I do some woodworking from time to time. Generally if I can measure from the wrong end, put the piece on the saw backwards or upside down, cut on the wrong side of the line, I'll do it. I have to check my work very carefully. I kept my focus pretty well on this assembly project so I'm quite pleased. I even deviated from the plans and didn't blow anything up!

The next step is to heat shrink the wires inside the case, tape down the cap and neaten things up a bit. Then I need to design the opto-isolation layer. More on that in my next post.