Having trouble wiring all this together

[Guyren Howe]

I've got my physical assembly done. I've got a Shield attached to my Mega 2560, with the 4 I guess they're stepper controllers mounted on top of that.

But how I wire all this together is less than entirely obvious.

I've got two power inputs — one on the arduino and one on the shield. I think they're both 5V so I guess I can probably just split my PSU and hook that up. ?

This page:

<http://reprap.org/wiki/Arduino_Mega_Pololu_Shield#Firmware_and_Pin_Assignments>

is useful but doesn't answer everything. What I am still confused about is:

- the stepper motor outputs are labelled RBGB, but the cords for my steppers are yellow, black, orange and red.

- which stepper gets wired to which output?

- the endstop wires are labelled gnd, sig, vcc but on the pololu page they're labelled XYZ(MIN) and there are six of them. Or there are three with six pins each. Either way, I've got twice as many pins as opto end stop connections.

- D8 and D9 don't appear to be used for anything. Seems odd to have them, then.

Also, regarding the firmware:

- which is the best firmware to use? How do I configure it?

I tried uploading the Tonokip firmware with the pins settings provided for the Pololu. There was a flurry of flashing lights, and then nothing. If I press the reset button, I get two flashes of the LED. Is that right?

When I try to build the firmware for the stepper controllers, I get the likes of this:

In file included from FiveD_GCode_Interpreter.cpp:9:

hostcom.h: In member function 'void hostcom::putInit()':

hostcom.h:111: error: 'Serial' was not declared in this scope

hostcom.h: In member function 'void hostcom::put(const char*)':

That will do for now, I think. :-)

[Mark Halls]

On 3/6/2011 2:21 PM, Guyren Howe wrote:

I've got my physical assembly done. I've got a Shield attached to my Mega 2560, with the 4 I guess they're stepper controllers mounted on top of that.

But how I wire all this together is less than entirely obvious.

I've got two power inputs � one on the arduino and one on the shield. I think they're both 5V so I guess I can probably just split my PSU and hook that up. ?

This page:

<http://reprap.org/wiki/Arduino_Mega_Pololu_Shield#Firmware_and_Pin_Assignments>

is useful but doesn't answer everything. What I am still confused about is:

- the stepper motor outputs are labelled RBGB, but the cords for my steppers are yellow, black, orange and red.

- which stepper gets wired to which output?

- the endstop wires are labelled gnd, sig, vcc but on the pololu page they're labelled XYZ(MIN) and there are six of them. Or there are three with six pins each. Either way, I've got twice as many pins as opto end stop connections.

- D8 and D9 don't appear to be used for anything. Seems odd to have them, then.

Also, regarding the firmware:

- which is the best firmware to use? How do I configure it?

I tried uploading the Tonokip firmware with the pins settings provided for the Pololu. There was a flurry of flashing lights, and then nothing. If I press the reset button, I get two flashes of the LED. Is that right?

When I try to build the firmware for the stepper controllers, I get the likes of this:

In file included from FiveD_GCode_Interpreter.cpp:9:

hostcom.h: In member function 'void hostcom::putInit()':

hostcom.h:111: error: 'Serial' was not declared in this scope

hostcom.h: In member function 'void hostcom::put(const char*)':

That will do for now, I think. :-)

I don't think you are doing it right. I'd have to see it to know more. Basically on the PSU you are only going to use the 2 outermost strands of wire, the core is a second ground if I remember correctly. You'll have to measure it with your multimeter to determine polarity.
Check out webchat.freenode.net and join the channel #reprap and ask there. Most of the people that are most knowledgeable hang out there.
I'll give it some more thought and let you know if I think of anything.
Mark

[Guyren Howe]

On Mar 6, 2011, at 16:41 , Mark Halls wrote:

> I don't think you are doing it right. I'd have to see it to know more. Basically on the PSU you are only going to use the 2 outermost strands of wire, the core is a second ground if I remember correctly. You'll have to measure it with your multimeter to determine polarity.

Thanks. But the issue it seemed to me is how you attach a wire to a cylinder of loose fine strands of wire. It's just that I haven't done this before. I clearly can't just solder a bunch of strands to another wire. Do I crimp something to the outside strands and something else to the inside strands, or what?

[Mark Halls]

Actually, you could just solder the outside strands of wire to one piece
of wire and the inside to another. As long as you use a wire of at lease
22 gauge it shouldn't cause enough resistance to heat up. You'd have to
do the math to find out how hot the joint would become but I soldered my
ebike together and that system runs at 24v and up to 30 amps, way more
than your psu will ever put out. Just twist the wires together on the
psu and pick a wire that is of a similar diameter and you should be
fine. Also be sure to use heat shrink tubing to insulate the connection
to prevent shorts. Other than that it should come together quite easily.
Let me know if you have any other questions.
Mark

[Guyren Howe]

On Mar 6, 2011, at 18:47 , Mark Halls wrote:

> Actually, you could just solder the outside strands of wire to one piece of wire and the inside to another. As long as you use a wire of at lease 22 gauge it shouldn't cause enough resistance to heat up. You'd have to do the math to find out how hot the joint would become but I soldered my ebike together and that system runs at 24v and up to 30 amps, way more than your psu will ever put out. Just twist the wires together on the psu and pick a wire that is of a similar diameter and you should be fine. Also be sure to use heat shrink tubing to insulate the connection to prevent shorts. Other than that it should come together quite easily.

Okay; I think that's good. Thanks.

[C.W. Holeman III]

What shield are you using?

--

C.W.Holeman III  
PHONE:(760) 512-4707

EMAIL: cwhole...@gmail.com   

WEBSITE: http://www.cwholemaniii.com

[Wilds Eyed]

Don't plug anything except USB into the Arduino!!!

Also, and I'm assuming you are using RAMPS, cut the diode, or remove it.  Having it on there increases the risk of blowing the arduino, and it's not really needed unless you are totally maxed out on USB devices drawing all you power.

The RAMPS shield takes the Yellow(+) and Black (-) leads from a PC power supply.  At least 450 Watts, more if you can afford it.  Especially if you plan on running fans, heated beds (for printing ABS), etc.

For the steppers, first find the wire pairs.  Turn the motor by hand, and short two wires.  If you feel the motor get harder to turn, you've found the pair.  If there is no difference, try another wire.  Once you've found the pairs, wire them up left to right.  Stepper Motors are usually A+A-B-B+.  If you get the motors connected and they don't seem to want to turn, flip the wires on one pair (only).

A note on adjusting the Pololu driver currents.  Gently turn the POT on each driver couter-clock-wise until it stops.  Again, GENTLY.  This is the low position.  The POT has a flat side to it.  This flat side should now be in the 7:30 position.  You want to set them all to 9:00 or 10:00 but no more.  If you feel your motors getting so hot that you cannot touch them for 5 seconds without going to the emergency room, you've set them too high.

End stops:  You only need the X-min, Y-min, and Z-min.  When making the cables, one end will be GND-POS-RET and the other will be GND-RET-POS.  This is different than other electronics where the cable is straight through.

Firmware should be Sprinter.  Software should be Portable SkeinFroge, and RepSnapper.