How do I connect the Extender to Cobra II Wifi?

I have a Cobra II Wifi and an Extender ( I am unclear as to how to connect them. The Extender came without any gadgeteer cables or instructions. The product page similarly contains no information. It also seems like there is a battery slot.

My questions.

  1. How do I actually connect the extender to the board?
  2. Does the extender need a battery. If so, what type?


It looks like you could do it several ways. Simplest would be to use a row of .1" male header soldered to the Cobra-II on one end and the extender on the other. This would be a fairly permanent way to do it. Another option would be to use a female header on the Cobra-II and a male header on the extender and insert one into the other. The would make the extender removable if it needs to be. A third option is possibly to align the boards perfectly and directly solder them via the through hole. That could be a bit tricky and difficult to undo if it didn’t work out.

I believe its optional to keep the RTC going. Looks like it uses a CR2032 but I can’t confirm that.

I was hoping for a gadgeteer-type answer, e.g. connecting the extender via a gadgeteer cable. Is there anyway to do that?

The extender’s purpose is to turn the pins along the header into Gadgeteer sockets, so it must be soldered pin-to-pin or using headers, as suggested by @ ianlee74

[quote=“ianlee74”]Another option would be to use a female header on the Cobra-II and a male header on the extender and insert one into the other. The would make the extender removable if it needs to be.

Could you point me to a place where I can buy these female and male headers? Does Radio Shack have something like that? Is it a standard size part or will I have to hunt for something Cobra || specific?

0.1" is a “standard” header size, yes. Not sure if RS will stock them, but here’s an example from ebay (where I buy all mine from).


If you count the # connectors there for me, I’ll send you a set from AU if you can wait.

Thanks for the offer. But I am trying to do soon, hopefully this weekend.

no worries. I just searched on for 0.1 and didn’t find anything. Perhaps the best option if you’re US based is and and find a local reseller/stockist?

Thanks, that’s perfect. Any idea why the Cobra II board and the extender have 41 pins instead of 40? Is the last pin unused?

40 is just an arbitrary number, and seems to be the common length of both of these connectors. I’d get a handful of each, and cut them as a group of 20 and 21, or some other combination that totals 41. Alternatively, if you didn’t want one of the end pins (VIN or P0.5; if you want to use CAN then you need to choose to not connect VIN). This way you could still solder a header or some other connector onto VIN to connect to a higher voltage source (the schematics of the extender don’t show the “12V” line being used anywhere else so it’s OK to not connect it, but if you have a multimeter you could check there’s no other exposed pad for this connection)

Well, if you want to do something this weekend and you can’t find the header a “gadgeteer-type” answer might be to find an old 40-wire IDE cable and use a piece of it to solder between the two boards. You could later remove it fairly easily if you wanted to replace with headers.

Can’t find female sockets for a 40 pin header on Mouser. Anyone had luck finding a pair of header pins with matching sockets on Mouser - to solder on each board?

Or anyone came up with a better solution?

@ njbuch - I got my male-female pair on ebay.

I bought a bunch on ebay as well. I use a lot, it seems, but I still have a lot too. I’d look at something like this or since you end up with a good quantity of both male and female.

Thanks guys, will buy a pile on ebay.

Considering that it would be a nice gestus of GHI to put a pair of headers with the extender board.