For you all you Pixhawk people out there. 3DR no longer sells parts (or, they have some) as they’ve left manufacturing exclusively to third parties like HobbyKing, whom 3DR approves of.
Do note that they’re working on an official Pixhawk 2 (or whatever it’s name will be)!
In the meantime (and for a long while yet), expanding IO on the Pixhawk requires buying or making cables to fit their specific build of Pixhawk. While 3DR chose Hirose connectors, many companies, including those making Pixhawk clones, chose to use JST connectors. Make sure to check which connectors are on yours! There are other connector types for all different Flight Controllers out there.
Hirose Connector female example (female plugs), but male connector:
Female (female connector, but male plugs – I get confused)
This page has a link to all the cables and connectors at DigiKey for the official 3DR PixHawk only. Make sure to check your Pixhawk – it may be called official, but it might be clone if you bought from Ebay and probably uses JST!
Since I’m hooking up to a Raspberry Pi I figured I could cut the ends off the female side, add the Hirose, then have a convenient cable without having to crimp on male ends.
UPDATE 3-4-2016 READ THIS BEFORE PROCEEDING!
Oh boy are these connectors tiny.
The PA-09 is a great tool for the price. The teeth are very finely cut and do a good job crimping
Crimping DF13 connectors is a nightmare. Would not recommend.
Other connectors that fit the teeth are *much* easier to crimp.
My cable idea above for DF13 connectors will not work: the insulation is too wide and is impossible to crimp (well, in my inexperienced hands). It might be possible to just crimp the wire itself since the PA-09s have really tight tolerances, but this is not recommended – maybe if you need wiring on the bench, but not if you’re taking something into the air with stress and vibration acting on the connectors.
As usual, when you would rather have some fun instead of doubling down on Google to find your solutions, I only found cables on Ebay shipping from China, or in Europe. I went back to Google and with a more determined search found a company in Florida that not only has their own PixHawks, but sells cables (5 and 6 pin DF13 connectors): Ready to Fly Quads
The best part is that sell a ton of stuff and are really inexpensive compared to many. Three feet of good silicon AW30 is $1. One dollar. Awesome.
Note: they also sell PixHawk based products that use other pin connectors, so if you’re shopping around make sure you’re selecting the right part. Many of their products have PDFs schematics so you can check, but they do also seem to describe what connectors are on the boards. Their MINIREADYTOFLYER / MINI APM 2.6 V3.1 uses JST, for example.