alden

Perhaps buying another grblshield? (hint hint) 🙂

Alden

Can’t answer your question about the toolchain, but no, you can always re-load the Arduino code from the Arduino menu (somewhere in the upper right part of the screen, IIRC).

Alden

There are no user changes required on the v1 board
(which, by the way, is the only version in production – there is no second thing…)

There was a note on the wiki about needing to remove a resistor if you didn’t want to configure the motor Enable line to be active LO, but this is unnecessary if you use the patched .HEX file, or (more recently) use the grbl 0.7 release from the grbl github edge branch. That wiki text has since been removed because it caused more confusion than it cured. You can ignore it in the hard copy instructions, too.

Alden

Here are some links I found by searching around that explain stepper basics and how to figure out what wire is what.

http://www.reuk.co.uk/Examining-a-Stepper-Motor.htm
http://digital.ni.com/public.nsf/allkb/0AEE7B9AD4B3E04186256ACE005D833B
http://techref.massmind.org/techref/io/stepper/wires.asp#step2 (for 5 wire motors)

Alden

Unraveling a motor without specs can be a challenge. I first always look for a data sheet by searching on the motor part#. It’s often on the motor, but not always. If I can’t find the data sheet it’s time for the ohmmeter.

Wire colors can be clues. Green and black are often the outer leads to a winding, and red and blue also often go together. Sometimes there will be a solid colored lead and a striped lead of the same color. These also usually go together. In a 4 wire motor (bipolar winding) if you test these pairs and they come back with the same low impedance (e.g. 4.2 ohms for a big motor, 92 ohms for a small one) you are done. These are the two windings.

In a 6 wire motor (unipolar winding) there will be an additional center-tap lead in between the outer leads. A white lead is often the center tap for the red / blue pair (red, white and blue), and a yellow lead is a center tap for the green / black pair. The ohmmeter will read 1/2 the resistance from the center to the outer leads. So if the resistance between the outer leads read 4.2 ohms, the resistance to the middle should be 2.1 ohms. I usually wire across the outer leads and leave the center alone (but insulated). I’m told you can also get higher torque (and consume more power) by running a unipolar just from the center to an outer, but I’ve never tried this (probably should).

Sometimes you are lucky enough to find a 6 pin header on your motor (the wrong size for your application, of course). Test these for outer1-center1-outer1, outer2-center2-outer2.

But don’t trust the colors and plug alone. I’m looking at a NEMA17 motor right now that’s 6 pin plug is wired green-black-yellow, red-blue-white. The colors are right, but the yellow and white center taps are not wired to the plug pinout the way I just described. Can’t be non-standard if there IS no standard.

So always test with an ohmmeter.

Mark, did you post your method somewhere?

Alden

Thanks. I’ve never done this and am curious about your results. One possibility is that since a stepper driver is just a kind of power amp, and you can parallel speakers to an audio amp, you should be able to do the same. OTOH, a lot of what the stepper driver does is damp back-EMF through various clever decay schemes, and if doubling up on the motors complicates the back-EMF waveform these schemes may not work. I’m curious as to your results. How good are you at soldering fine-pitch surface mount 🙂

We realize the problem and apologize for your inconvenience. We will begin selling the connectors in kits on the site so they can be packed with the order.

We also have located some really nice copper heatsinks that we also want to make available in kits. We’ve found that the TI drivers actually do quite well without any external heatsinking as the boards have as much copper as we could get – given the limited footprint of a shield. But the heatsinks extend that range a bit further.

If there are any other parts you think would be helpful, please let us know.

test post