Internal connectors (sensor, battery and power switch)

[fmckeogh]

Current design uses 2.54mm headers, but these have a large footprint and when plugged in make mounting in a small enclosure impossible. One goal of this project is to be compatible with many different enclosures to suit different users, but it does not fit in this design, even though the actual PCB size is more than small enough.

Direct soldering wires is an alternative, but makes replacing difficult and really not suitable for the battery, which definitely needs a keyed connector.

I see 3 main solutions:

• Right angled 2.54mm header pins, extending over the board, like in this picture:
  This adds a bit of vertical height, which standoffs would have to account for, as well as routing the cables and stays 2.54mm compatible which is nice. Not keyed, so could be problematic for battery.

• JST-XH. Keyed, so good for battery. Not technically 2.54mm compatible, but for low pin counts is close enough to work. Straightforward to hand-crimp custom connectors. Still fairly large, plus the 3 pin ADC could lead to someone accidentally plugging in a 2S LiPo, but that's a weak reason.

• JST-PH. Keyed and small, also very common on 1s batteries, so easier to assemble. WouldFairly common in the UAV space. Difficult to crimp, and more delicate. Less likely someone building their own bluefly would have the connectors than XH or right angled.

Currently I am really leaning towards JST-PH, mainly due to size and being common for 1s batteries. I plan on keeping the 4 SWD pads, spaced 2.54mm apart, so a header can be soldered on for debugging.