I’ve gotten my hands on a CNC mill that uses a Gecko G540 and I would really like to change out the current motion controller for a Smoothieboard. I understand (or think I understand) that the easiest way to accomplish that would be with a parallel shield, but the shield is “coming soon” and not in stock… does anyone know when they’re likely to be back in stock?
The github repo for the shield shows the last activity as being two years ago, so I have a feeling it may not be coming soon to a retailer near me. As it’s open source (hooray!) I could always make my own from the provided source… but it’s so much easier (and usually a bit cheaper) to buy from a commercial source. Is there another source for the shield that I’m not finding, or am I probably doing to be making my own?
I take that back, there’s some surface mount parts. You can get the boards easily but getting those parts soldered on might be a challenge if you don’t have such soldering experience.
The Gecko drive basically only needs step and dir inputs, so I could chop up an old parallel cable and wire the appropriate pins as external drivers, but I was under the impression that that’s effectively what the parallel shield does, just a lot more neatly than a chopped up cable.
You really don’t need the parralel shield, just wire the drivers to the Smoothieboard directly and you are good to go, it’s really easy.
Note that we’ve had quite a few reports now about geckos being much more difficult to tune/get to work right than other drivers ( like leadshine and friends ), but I guess if you already have the drivers you can’t do much about that.
Hm… well, the Gecko drive unexpectedly came with the machine. I was actually expecting to have to completely replace the electronics, and had planned to either just use a Smoothieboard or use a Smoothie with the MassMind high powered drivers as external drivers depending on what I went with for steppers. So I’m not opposed to pulling out and selling off the electronics I’ve got now.
The machine itself is very old, from the mid-80s, and I had expected equally old proprietary electronics with geared servo motors but found steppers and modern electronics to my pleasant surprise. It would be nice to just have to swap out the motion controller, but it would also be nice to have it work well, so a full refit may still be in order.
The level shifters on the parallel port adapter might help with the Gecko drives. It shouldn’t be necessary, but Gecko with smoothie seems to be hit or miss. I initially had a hard time but it worked well later. I never did figure out exactly what I did wrong before.
@Jeff_DeMaagd You can wire smoothie’s pins as open-drain, then they can be used as a 5V output, so there is not much need for a level shifter in that situation.
@Arthur_Wolf Do I need to wire in an external pull-up to use Smoothie’s pins as a 5v open-drain? Does configuring with internal pull-up make it 5v or 3.3v out? Can I configure the PWM (laser control) pin as a 5v output? Say, laser_module_pin 2.5^o ? …maybe have to invert it.
Cool - I need an o-scope, to check things out. I just looked over the smoothie schematic… or I think I could use one of the small FETs, just use 5v in for the power side, if I understand it correctly. I need to look at the CPU data sheet.
