jig mania

[simonbaker]

For testing different cables with different PCBs and different coils, I needed some solution match the coil wiring to the PCB wiring.

I have one PCB that uses green & white USB wires for TX coil and red & black for RX coil.

Other PCBs use the opposite.

The special problem is that, at the coil end, sometimes the cable shield wire needs to connect to the black wire, and sometimes to the green wire, depending on the PCB.

Or maybe not. Do we really need to have the shield always connect to the TX ground at the coil head (since it already connects to the TX ground at the PCB)? Could we just connect it to the coil shielding? Maybe something to experiment with.

So I used some "header" pins and sockets to help choose these configurations more easily and match my various coils and PCBs.

Attached are some photos. Note that the cable shield wire is the yellow one and is free. I can plug it in to either end of my socket. Note also the end socket pins are soldered to the one next to them. That way I can choose which wire, green or black, is connected to the shield at the coil.

The socket wires are then soldered to the TX and RX coil leads directly.

I'll probably find a better way to do this. It is actually awkward to insert the cable pins into the socket separately because not much slack to maneuver.

P.S. I loathe alligator clips that won't bite a wire because of gaps. I'm also not fond of these cheap solder jigs with two arms with alligators -- they are a pain to line up. We need jigs where each side holds something at a given orientation and height, and you can slide the two sides together on a track. Anyway...

-SB

[simonbaker]

better

Yep, already changed my mind for a better way -- not quite as flexible, but does the job and quicker to use.

Idea is to use a 5 pin male header (not 5 separate pins), and put the cable shield on the center pin, with the black and green wires (possible TX grounds) on either side.

Then wire the socket with black and red wires always for TX by convention. Ground the black wire to the center pin so it always connects to the cable shield.

If the PCB uses green and white for TX wires (with green ground), just flip the cable header to match the cable green wire with the socket black wire and the cable white wire with the socket red wire. Dig it? Should help with experiments where I switch cables and coils etc.

-SB