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geekhack Projects => Making Stuff Together! => Topic started by: iMagUdspEllr on Mon, 20 April 2020, 17:22:12

Title: Double-sided magnetic cable
Post by: iMagUdspEllr on Mon, 20 April 2020, 17:22:12
Tl;dr: I spliced two cables with magnetic connectors together in order to create a cable that has magnetic connectors on both ends. This didn't work. I'm not sure what I'm doing wrong.

I read some articles that inspired me to build a custom USB cable for my keyboard. I thought I would try to do something more ambitious than just put paracord and TechFlex on a USB cable that I assembled myself. I like the idea of using magnetic cables to make plugging and unplugging my custom keyboard and taking it various places even more streamlined. I know that I can buy magnetic cables off the shelf. But, all of them seem to only have one end that is magnetic and the other end is usually USB type A. I thought I would simply cut off the Type-A connectors and splice two magnetic ends together and I would have a double-sided magnetic cable that I desire.

However, this didn't work. I tried to solder red, black, green and white wires to each other; this didn't work. I tried to solder red to black, black to red, green to white, and white to green; this also didn't work. I noticed that these magnetic connectors have an LED. This means I would have one more LED in the cable than it would normally have. My basic knowledge of electronics tells me that diodes only allow current to flow in one direction. But, all of the continuity checks that I have made with my multimeter seem to tell me that everything is flowing properly and I don't have any shorts between the hot and return wires. I seem to have the proper continuity between the appropriate contacts on both connectors.

In order to remove the LEDs from the circuit in order to reduce the complexity of this problem, I would have to destroy the connectors. I would be able to leave them functional, but they would be ugly and I don't think I can acquire replacement housings that would leave my finished product looking marginally professional.

Would anyone be able to point me in the right direction or tell me why this is difficult and in doing so explain why I can't simply buy a cable like this off-the-shelf? Thank you for your time and assistance.
Title: Re: Double-sided magnetic cable
Post by: Leslieann on Mon, 20 April 2020, 19:11:37
I'm betting the diodes are the issue as each is facing the opposite direction. This would explain why the cable options are a bit limited as well (I.E. no type C to type C magnetic, it's always A to something else).

There are some that don't have LEDs and there are some short extension/adapters that add magnetics, also without leds. Just remember if you combine it with one with an LED the cable will be directional.
Title: Re: Double-sided magnetic cable
Post by: iMagUdspEllr on Tue, 21 April 2020, 02:14:40
Thanks for the help. It seems like it would be simplest to buy those extensions. I appreciate you taking the time to reply.
Title: Re: Double-sided magnetic cable
Post by: Leslieann on Tue, 21 April 2020, 02:23:04
Thanks for the help. It seems like it would be simplest to buy those extensions. I appreciate you taking the time to reply.
You're welcome, good luck and post pics when it's done.
Title: Re: Double-sided magnetic cable
Post by: Leslieann on Sat, 09 May 2020, 20:19:32
Just an update on this and info for anyone else trying to mess with cables like this...
If you are making a Type C cable for a device not originally Type C to plug into a Type C port, in order to be detected, Type C devices need a resistor across two pins.

Simple chopping the end and swapping the connector like we used to do no longer works on Type C thanks to this change in the USB spec. This is why it's not a simple matter of changing the mini B on a keyboard, Arduino, mouse, cell phone to Type C. Again, this only applies if you are plugging into a type C port on the computer.

Here's a video that gives a better explanation.
Title: Re: Double-sided magnetic cable
Post by: iMagUdspEllr on Tue, 16 March 2021, 06:35:31
This isn't as slick and DIY as I initially intended. But, this accomplishes the basic idea of what I set out to accomplish and gives me the flexibility to connect to USB A or C as needed.