Making PWM Cables
 

We have heard from other teams that they make their own PWM cables so that they can spend less money and also have them be a custom length. This year, we want to do that. However, upon looking at the prices of cable, connector housing, and connectors, they are turning out to be rather expensive, actually a bit more expensive than buying pre-made cables.

I was wondering where teams who do this buy their cables, because either I was misinformed or I'm just looking on the wrong websites. Thanks.

Re: Making PWM Cables
 

This is where we got ours. Good prices, good service. Support the small buisness. They are cheaper than premade, and you get to make them to length so they look nicer. They do take practice!

http://www.hansenhobbies.com/products/

Re: Making PWM Cables
 

We bought from Hanson Hobbies. Still think we didn't get the best price, but we got what we needed. We also bought their PWM crimping tool that makes those tiny connectors a lot easier. http://hansenhobbies.com/products/connectors/

The pwm spots on the digital side car are actually designed for molex connectors(surprise right? Part number is in their documents). And the male connectors are available on digikey. I don't have the thread of the top of my head but a quick search for making your own pwm cables will pull it up. Just crimp, assemble and succeed.
Not cheaper, but is neater and connects easier.

Re: Making PWM Cables
 

Hansen Hobbies is great and I haven't found a better price. If you make the PWM cables so that the clips that hold the pins in point towards the clip on the sidecar, they latch and hold pretty well, though I'm sure not as well as the proper Molex connector would.

Re: Making PWM Cables
 

Here's some Digikey Part numbers, in case you're interested. I'd also recommend picking up one of the crimping tools, as they're really useful.

Male connectors: WM2515-ND
Female connectors: WM2512-ND
3 connector housings: WM2801-ND
3 conductor wire: A121-500-ND (note, this is not the Red/Black/White flat wire that you're familiar with, but it'll function just the same, and I'm pretty sure it's cheaper - at least it was this time last year)

Re: Making PWM Cables
 

another good way is to buy pre-crimped cables. Pololu sells some nice ones that I've used for all sorts of projects. Use the 12" ones on the bench for testing, then use the other lengths (up to 60") on the robot.

Wires housings

if you have some kind of sensor that goes from two Digital ports to a single connector, you can make the right combo cable.

The other advantage to this is that you have 8 colors to choose from for the signal wire, so you can color code which cable goes to which speed controller for a quick sanity check.

Re: Making PWM Cables
 

Is it me or is the price at Digikey much more expensive. I just ordered 300 male and female pins, as well as 100 feet of cable from Hansen Hobbies

Hansen Hobbies
$17.13 - 300 female pins
$17.13 - 300 male pins
$30.95 - 100ft cable

Digikey
$25.67 - 300 female pins
$41.57 - 300 male pins
$194.76 - 500ft cable Only comes in spools of 500

Re: Making PWM Cables
 

We're making our own as well.

Housings: Molex 50-57-9003

Female contacts: Molex 16-02-1114 These are called "high force" contacts and should stay put while the robot is getting beat up.

I really don't like the formed male contacts. We've gone a different route and are making our own using the female contacts and soldering 0.025" header pins into them prior to crimping. It takes some time doing this with 0.016" solder under magnification, but were getting stronger, straighter pins. Make sure you're using the right crimper and pull-test every pin.

Just about any 22AWG wire will do. We're using very finely stranded stuff (about 100 strands) intended for high motion applications.

Re: Making PWM Cables
 

What issues have you had with the male contacts?

Re: Making PWM Cables
 

The formed males can be very fragile. The slightest accidently bend and the pin may break off. Hansen sells double ended (solid pin) male "headers" that have long pins at both ends (as opposed to long one end, short the other). We made our encoder connectors all female, and used a piece of that header to turn one female end into a male. Not sure if that would work for connectors targeted for victor with its hooded pwm connector.

Re: Making PWM Cables
 

If you are willing to solder each pin and do a bit of finishing work you can also use snap-able headers in either male or female format. Snap off a 2 - 3 - or 4 pin section solder wires and finish with heat shrink for a custom connector. You may need a small dab of epoxy in some situations to hold the pins better and produce a more rugged connector. The female version requires sacrificing one pin for each cut and some sanding or filing to produce a clean edge.

You can also epoxy three 14 pin lengths together and solder them to a piece of proto-board to build a digital I/O breakout board. Add other connectors and pins to build a custom connector that allows you to access the signals for testing without removing the PWM connectors, or to transition to some other type of connector to get away from PWM cables entirely. At least at that end.