How come you pay $20 for 24" of pwm cable, when for $20 you could get 144" of cable?
I just think that the prices should be reviewed a little, i mean you get 6 times the amount of cable for the same price!
I don’t really think these are accurately priced, the 6" cables should be $10
12" cables should be $15, 24" cables should be $20, 36" cables should be $25.
I am sorry for critizing the products so much but this is a little messed up, the best value is the 36" cable pack but unlike the metal you cant cut the cables shorter! or i would have bought them.
I think the bulk of the cost is in the connectors, assembly, packaging, and distribution. The incremental cost of the wire is probably negligible (a few cents). Since they are all the same price, I buy the longer ones and zip-tie the extra wire.
I really wish Vexlabs would make the connector housings/pins available. Aren’t they the same as the futaba servo connector housings, but with male pins instead of female pins? Does anybody know of a source of these?
I found these, which look like just the ticket. They sell a pack of 10 futaba servo connectors (with female contacts) as well as the other end (with male contacts). I’m 99% sure you could use these for custom Vex cables if you just swapped the male/female contacts. I’ve never ordered from these guys, but $9 would get you enough connectors for ten extension cables.
The question of gender naming of connectors on model aircraft pwm cables is vexing. Unlike all the rest of the world, the end of the cable with the pins (the males) is called female when they put that outer shell on it. Just a hint that when you ask for male or female connectors you need to look closely to make sure you are getting what you want.
Right. I’ve always disliked designs where the powered end of the cable has exposed (male) contacts. An R/C vehicle with a conventional PWM extension cable that comes unplugged will have exposed live pins that could short out and fry your receiver/controller or blow a fuse.
I’ve assumed that Vex chose to buck with the R/C tradition and put the pins on the unpowered side for this reason. A Vexbot has a lot more exposed metal than typical R/C vehicles, so a loose extension cable with powered pins would be much more likely to find a short. The gender arrangement they settled on makes for some mild frustration when interfacing outside of the Vex family, but is (IMHO) better than the R/C industry standard.
I just ordered a bunch of these and they are identical to the Vex connector, except the little tab is on the opposite edge (like a mirror image).
Generic .1" connectors work OK, but I’d really like to find a source of connectors with the polarizing tab in the right place. Does anybody know of a source?
Getting connector housings that fit isn’t difficult, since they are available at Digikey and Jameco. What I really want is the ones that fit only the right way. Any students that use my hand-crafted add-ons would be ensured of plugging them in the right way around. Without the Vex connectors, they have a 50/50 chance if they aren’t paying attention to the wire colors.
A few years later, I finally got around to making my own. It is surprisingly quick and easy.
Just start with a standard 4P housing, and use snippers and a craft knife to end up with something like this:
