I don’t see any specifications for servo wires for connecting the motors to the servo rail on the Pixhawk. I understand different brands of servo wires and their connectors are different. Which type of servo wire is ideal for Pixhawk? I mean like Futaba, JR, Airtronics…
I am also wondering about if there is any problem if I use longer servo wires? Is there a limit to the length I should use?
I believe the futaba style is technically the one to use. It has the key tab.
That being said… All of these connectors are essentially copies of the original dupont connector for header pins on 0.1“ pitch. So that is the underlying design.
As with most electrical connectors, you get what you pay for. Cheap connectors from Amazon or eBay will not fit snug no matter what style they’re trying to replicate. So TL:DR - if snug fit is what you want, it’s more important to spend the money on good connectors that any particular style.
Ok. Lots of references to Futaba connectors. One thing: I read that Futaba uses different size pins and crimp terminals and can lead to the female side of the connection becoming loose if mixed. What’s this all about?
Still wondering about the maximum length of servo wires I can use for connecting my ESC’s.
I doubt you’ll have a problem. I would use 22AWG twisted wire to add a bit of noise immunity. You might consider something like these and just cut the female end off at the length that you need. I would not leave a lot of excess. This will save the necessity of crimping the connectors yourself.
I like these as I trust the vendor and like the idea of a gold plated connector. Pretty sure these are JR style however:
I think I’ll twist up my own, cut perfectly to length. I already have a few meters of 22awg servo wire and some Futaba connectors with the directional tab. I also have some extenders, but I don’t like the idea of introducing another connector for the reasons of resistance and it opens up another point of failure. Nice to know 80cm is no problem though.
I wouldn’t use 80cm if I could avoid it, that was just a length that the vendor carried in stock. Short as practical would be my goal. You will want extra for comfortably routing to the FC etc. I doubt you’ll be much more than 40CM per arm, but that is a big aircraft.
Absolutely, if you have the cable and terminals and are comfortable crimping them, then that’s a good way to go. Agreed that an extension is a point of failure. Sounds like you are ahead of the game
“Use as short wires as possible or even better, use a standard 3 position JR servo connector with the diode legs directly inserted (and soldered) in the servo female pins. To complement the diode, it is also useful to add a capacitor in parallel to the diode. The capacitor will smooth out eventual voltage ripples.”
So I’ve now got some JR style connectors on the way. It could be that the connectors I bought are just poorly designed and too thick for how a true Futaba connector should be - mine are most likely generic.
I also like to keep them as short as possible. Too long wires can catch noise. Twisting signal and gnd helps if the wire is longer than usual. Regarding the plug, beside being important the housing, the crimp itself is a huge part also. I’ve seen a lot of cheap cables poorly crimped and failing over time. I read some time ago this guide:
It is the most complete I’ve found about the kind of plugs we usually use. Ideally one of those crimpers is the best, I found one of them pretty cheap in ebay. Regarding cheap crimp tools, not all of them are good. If the dyes are not precise it can mess up the plug and compress it where it shouldn’t and can fail over time also. I’ve heard a lot of good things about the crimp tool of hansenhobbies, and it is cheap. Their connectors are also good quality.
I went ahead and ordered one of the economy crimping tools from HansenHobbies.com. For now, I’ve got everything hooked up and working but plan to re-do all the wiring using gold plated connectors, perfect length twisted wires, etc. after the crimp tool arrives.
edit: Tool arrived and was able to make some very nice crimps onto some test wire then a zener diode and capacitor for my Pixhawk. When the wires arrive, will be making custom twisted lengths. Great tool for reasonable price. Feels well built.
The Engineer PA-09 is the only ‘budget’ crimper worth anything. I promise it will save you from cursing at your work. Everyone, including myself, thinks ‘how much difference could there be? its just a crimping tool!’. It makes a huge difference.