wiring small cables to big connectors? - Page 1
Forum section: electronics / projects

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 08:19:08 am
content: A couple of days ago posted about the below paradox. How to wire from a small PCB which lends itself to JST SH connectors with 28AWG wires to "big" pushbuttons that have spade connectors that require much larger AWG wires in order to be able to crimp.There was no interest and somebody apparently cares enough to delete the post. Here's a photo to illustrate the point.In any case, current best solution doesn't involve wires but Capacitive Touch and 1206 SMD LEDs mounted on the reverse side of the board. The design files for the MCP product can be downloaded which is very kind of them and there's a microcontroller with capacity to spare so why not?https://youtu.be/hX4z93zoTnk?t=35Still interested to know how to deal with the wiring thing...

author: MarkF
author_rank: Super Contributor
timestamp: March 22, 2019, 09:26:04 am
content: Can you just solder the wires to the switch...Don't bother with a spade connector. Some of the spade terminals I've seen have holes.Solder and heatshrink for strain relief.

author: Rerouter
author_rank: Super Contributor
timestamp: March 22, 2019, 09:34:08 am
content: https://digitalyacht.net/2015/03/26/crimping-small-wires/foldback the wire and use the proper crimpers not the crappy die ones that are built into wire strippers.

author: timgiles
author_rank: Regular Contributor
timestamp: March 22, 2019, 10:42:08 am
content: Nice to know. Thanks for posting and the answer.

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 03:05:15 pm
content: If yachtsmen bend their wires before crimping then it must be reliable. Great tip, thanks. Think for 28AWG might have to bend more than once...Love to solder! Check out this recent masterpiece: RJ11 via 28AWG to 24 AWG rigid wire (for power supply hook clips) and to 100ohm resistor (to keep the CANbus happy). I have a friend who fixes the holes in the pockets of his jeans with hot glue. Says it lasts them out. However somebody told me soldered connections weren't very pro so am trying to move away from it.

author: coppercone2
author_rank: Super Contributor
timestamp: March 22, 2019, 03:09:18 pm
content: You are not supposed to put insulation inside the deforming part of the crimp where the electrical contact is made to my knowledge.Fold the wire back over itself but it should be bare metal in there. Plastic can creep much more easily then copper.What I did if its aridiculousfit is to make a solder junction between the wire with a thicker wire using good practices then crimp the good wire properly and just rely on the solder joint rather then trying to hack the reliability of a connector.I am not convinced some kind of hack is going to offer better reliability then a solder joint and a proper crimp put together. It's going to be worse then just one crimp but I think it beats a hack.

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 04:20:48 pm
content: Good thinking. If you do a soldered wire-wire joint do you heatshrink or use tape?On the other hand the principle of a JST-XH, for example is that there's one part crimped on the insulated wire and one part crimped on the naked wires. So maybe crimping the lot together is not completely mad.

author: soldar
author_rank: Super Contributor
timestamp: March 22, 2019, 04:41:50 pm
content: Quote from: k8943 on March 22, 2019, 08:19:08 amWhat do you mean?

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 04:45:55 pm
content: Posted on Weds 21st in this part of the forum; on Thursday noted there were no replies; today couldn't find the post any longer. Fair enough, better to have a clean forum. Or maybe I just couldn't find it, but did look back in date order.

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 04:46:39 pm
content: Hmm just wrote Weds 21st... maybe that was it... it was the 20th Weds?....EDIT - no don't see the post for the 20th either, so think it was deleted. Which is fine.

author: Gyro
author_rank: Super Contributor
timestamp: March 22, 2019, 04:55:35 pm
content: Nobody deleted it. I can scroll back a page and see it - Which is fine.

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 05:00:48 pm
content: Ha! So I posted it on THURSDAY. Hmm time flies / warps / becomes re-entrant when you're searching datasheets and headscratching solutions. Now apparently I have a paranoic streak? No known cure.

author: coppercone2
author_rank: Super Contributor
timestamp: March 22, 2019, 05:40:37 pm
content: double layer heatshrink after you do a nice wire to wire joint

author: k8943
author_rank: Regular Contributor
timestamp: March 22, 2019, 06:01:41 pm
content: Sounds like magic. Have just ordered some 1, 2, 3mm heatshrink just in case...

author: soldar
author_rank: Super Contributor
timestamp: March 22, 2019, 08:14:11 pm
content: Quote from: k8943 on March 22, 2019, 04:45:55 pmJust search for your own posts. They are all there.