PDA

View Full Version : AX-12 Cables



sarendt
03-14-2011, 01:19 AM
Greetings,

I was looking at buying some wire and connectors to build up some new cables for my AX-12's and was surprised to find Trossen didn't carry any thing. Does anyone else do this? Maybe Trossen would start to carry some stuff if there was enough interest? (Andrew/Alex??)

My main concern is buying wire, I looked at some nice ribbon cable I think would work well.

http://www.newark.com/molex/88803-0016/ribbon-cable-idt-3way-30-5m/dp/35M3458

but its about 100.00 bucks for 100 ft, and I realistically only need 10-20 ft.

Anyone else have any thoughts/ideas?

Cheers,
Scott

iBot
03-14-2011, 05:59 AM
The standard AX plugs are crimp not IDC. Ribbon cable is not so easy to crimp by hand and not easily available in heavier gauge and more flexible versions. You would have to carefully route the cable to make sure it always bent in the right direction. If you want to use ribbon, then the coloured stuff splits quite easily between colors, so get any width from surplus or broken equipment and split it.

The biggest issue in making connectors is the crimping. You need a very small crimp tool and have to get exactly the right pressure to ensure a high quality crimp. Sometimes even a good crimp will distort the pin, making later intermittent problems.

I make my own cables for prototypes and development, but use Robotis cables on final robots wherever possible.

sarendt
03-14-2011, 08:21 AM
When I make my own I will most likely just solder the wire to the sockets, as I just can't justify paying 100 - 200 bucks for the crimp tool. I have made some cables before, not a production quantity for sure, but they were usually in the 20-40 pin style and had multiple requirements for shielding and jackets etc. I can't imagine that these tiny three pin's would be to difficult.

As far as the wire goes, currently I am just prototyping and testing the servo's so I don't need to worry about the wires bending much, but I can see how that could become an issue if they were going through multiple bends in a small area. Does anyone use shielded wires? If so how do you ground the shield after the first servo?

Cheers,
Scott

lnxfergy
03-14-2011, 08:58 AM
When making AX cables -- you really want them to be something like stranded silicone wire so that they can bend a lot and not break, regular wire degrades fast on a moving robot.

The connectors and pins are quite cheap at Digikey. You *can* crimp them without an expensive tool. The $10 crimpers from Radio Shack, or even a pair of pliers will suffice. Give yourself a few spare pins to learn on, and you should have no problem. Many of my bots have custom wiring harnesses in them -- since I can't buy an off-the-shelf 3' long AX cable.

-Fergs

sarendt
03-14-2011, 09:11 AM
Thanks Fergs, that is more what I was thinking :*)

-Scott

tician
03-14-2011, 10:32 PM
Just placed an order today for 500 crimp pins (http://search.digikey.com/scripts/DkSearch/dksus.dll?PName?Name=WM18889CT-ND) from digikey (along with ~$200 in other parts). Hopefully this cheap-ish crimper (http://search.digikey.com/scripts/DkSearch/dksus.dll?PName?Name=WM9999-ND) will work, but I should know for certain in ~4 days. As the project the 3-pin connectors are currently intended for will be stationary and connected over significant distances, I plan to buy the cheapest 3/4-conductor cable I can find.. When I do start with the actual replacement cables for the AX-12+, I think I will probably be going with Jon Hylands' recommendation (http://forums.trossenrobotics.com/showthread.php?p=40706#post40706) (or maybe this (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=461-1114-ND) or this (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=461-1116-ND)).



EDIT: Had suggested a $25 250-ft pull box of 4-wire phone cable from RadioShack, but that's not gonna happen with ~$72 shipping.

sarendt
03-15-2011, 12:42 AM
I think I will probably be going with Jon Hylands' recommendation (http://forums.trossenrobotics.com/showthread.php?p=40706#post40706)In this post Jon Hyland says to use 20 AWG but what I read on Digi Key was that the connectors are for 22-28 AWG. Can anyone elaborate on this?

Also, thanks for all the help guys :*)

Cheers,
Scott

tician
03-15-2011, 03:14 AM
I'm guessing the 22-28 AWG rating is not absolute. Looking at the dimensions in the datasheet, it may be possible for 20 AWG wire (with its diameter of 0.812mm) to be properly secured in the crimp opening. I'll give it a try when I get the parts and see how large a wire I can fit in the pin.