
Making Your Own Custom USB Cables - mindcrime
https://geekhack.org/index.php?topic=44924.0
======
rahimnathwani
"you might end up spending more than what several of the artisans out there
charge for a single cable"

Artisanal USB cables? Seriously?

~~~
pcr0
Geekhack is a community primarily focused around mechanical keyboards. When
you spend >$200 on a keyboard, $30 for a handmade USB cable to match your
keyboard isn't too bad. Given the amount of customization you could have in a
USB cable, mass production isn't cost effective and that's why they're
handmade.

~~~
wlesieutre
For reference:
[https://i.redd.it/l2qmqefggm0z.jpg](https://i.redd.it/l2qmqefggm0z.jpg)

~~~
ditn
What keyboard is this? It's beautiful.

~~~
aloisdg
Keycaps are a SA "1976" Keycap Set. You can get it on Massdrop:
[https://www.massdrop.com/buy/nineteenseventysix-sa-keycap-
se...](https://www.massdrop.com/buy/nineteenseventysix-sa-keycap-set)

You should browse /r/mk:
[https://www.reddit.com/r/MechanicalKeyboards/](https://www.reddit.com/r/MechanicalKeyboards/)
:)

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Theodores
In the early days of home computing and the early days of the PC it was a
common requirement to roll your own cables. Getting the pin-out of a parallel
port soldered up correctly was not so simple, even RS-232 serial cables were
harder than the USB to get right.

I can't fully remember why it was required to make such cables on a regular
basis but it happened. It seems that USB has not only made cable soldering a
lot easier it has also removed the practical need to do so. Either that or I
am no longer a 'hobbyist' with interest in such things.

~~~
siberianbear
I remember all that! I ran a BBS for awhile. For some reason, I couldn't find
a RS-232 cable that routed the ring indicator correctly. I had to build my own
cable with parts from Radio Shack.

------
Z1515M8147
A friend of mine recently told me about his partner who has been issued with a
device by doctors to manage a long term health condition. It was provided with
a USB A to USB Micro B cable, which it uses for its power, but no additional
peripherals (i.e. no proprietary mains-USB power supply) were provided. A week
after getting the device, it's needed in an emergency while on holiday, so
they run to the car to get a usb cable to power the device from a USB power
bank. Surprise surprise, the device would not power on. The workaround in this
case was that they fortunately had a very short 10cm usb cable stashed away in
the car from an old Raspberry Pi project, and this short cable worked.

The current theory (no pun intended) is that the VBus and ground wires within
the provided USB cable (which they had forgotten to bring) are thicker than
standard guage and/or that the power management circuit on the input to the
device has an undervoltage limit set in hardware that is set too strictly,
effectively locking you out from using any standard usb cable (30AWG wires
typically), even though the provided cable looks totally ordinary from the
outside. I would not be surprised at this as there are many companies that
make 'data block' USB cables that omit D+/D- wires and instead beef up the
VBus and ground wires, but look like a totally ordinary USB cable. There are
also companies that parallel the D+/D- with VBus/GND for greater current
capacity, but you wouldn't know without taking it apart.

I find it astonishing that a device designed for use in potential medical
emergencies could have been designed this way with no warning of this in its
manual, or if if this is a hardware bug that this issue was not discovered
very quickly during hardware verification tests (if indeed any were
performed).

Coincidentally i was recently having issues with charging of USB power bank.
Very similarly I was trying to charge the power bank with a USB A to Micro B
cable from a mains USB charger and thought that the power bank was charging
quite slowly. I hooked it up to a current clamp and it turns out that wiggling
the micro B end of the cable when it's mated to the Micro B receptacle on the
power bank swings the charge current anywhere from from 100mA to 1A. I
borrowed a 'custom' USB cable that a friend had bought off Amazon and it was
even worse, not budging above 300mA. Incidentally, the power bank states it
can handle 2.1A charging current on its micro B input (which curiously appears
to be above the specification of a micro B receptacle but that's a separate
issue). Only by making a custom cable myself, using 20AWG power and ground
wires, using a high quality $5 Hirose micro B plug and then epoxying the
connector ends to make a tight fit was I able to get the 2.1A charging
current.

I find it concerning and I'm really not convinced adding charging capability
to the USB specification as early as they did was a good idea. Having said
that, they were probably just trying to standardise what a lot of people were
abusing USB for already.

TLDR; not all USB cables are made equal. We live in times of mass usage and
abusage of USB. Be careful out there.

~~~
dogma1138
Voltage droop is a real issue for many cables not just USB ones. It's a much
bigger issue when you use them for power, it's a pretty well known issue that
cable length and gauge can have (a pretty big) effect on charge speeds. It's
even a bigger issue on the higher end devices that will limit the charge not
only based on voltage but also on current, basically if the cable can't
deliver the the 2 amps they'll drop down to 500ma or even lower.

I've switched most of my USB charging cables to those which I know are 20AWG,
the funny thing is that these cables aren't even more expensive I got mine
from
[http://www.portablepowersupplies.co.uk/](http://www.portablepowersupplies.co.uk/)
and they are cheaper than most cables on Amazon....

------
jerluc
Would love to see a similar post for USB C. I've been trying to find some way
of doing a right-angle with these, but without much luck.

~~~
Z1515M8147
I have found the best way to get right angled USB connection that can be
repeatably and reliably wired and is robust for rugged use is to create a
small interface PCB in CAD software like Eagle and use a PCB mount receptacle
rather than a straight inline/wire-to variant.

The PCB only needs to be big enough to land a through-hole usb connector [1]
and then bring copper traces from each pin perpendicular to the connector to
the edge of the PCB. You can even make the PCB quite long If you want to you
as this will give you long copper traces you can expose to land the wire ends
on, which is very useful if you don't have a great soldering iron or don't
have much experience soldering. You could even 3D print an overmould to make
it look professional, otherwise epoxy. Using this method you can get an right
angled usb that's a tighter angle than anything you'll find online because it
doesn't rely on cable bend radius to make the angle.

[1] [https://www.digikey.com/product-detail/en/mill-max-
manufactu...](https://www.digikey.com/product-detail/en/mill-max-
manufacturing-corp/898-43-024-90-310000/ED1391CT-ND/5213140)

~~~
StavrosK
That's a pretty cool idea. However, I see two rows of pins on that connector,
doesn't that matter? Are you making a two-sided PCB, or are you just soldering
the pins together? I'm not sure if they're the same or not.

~~~
Z1515M8147
Credit goes to Hirose for the idea on USB Micro B, as they hint at it their ZX
catalogue [1], but logically everything on USB devices is normally a
receptacle_ so custom cables really is the only use for a PCB mount _plug_. If
you download the catalogue and scroll to page 3 you can see example 3D renders
on the second half of that page that might make it a bit more obvious what I
was describing.

In actual fact for USB C you'd probably end up having to mount all connectors
in the cables on tiny PCBs regardless, because of the potential requirements
for signal conditioning and electronic marking ICs unique to USB C
implementations. With so many pins on usb C without a doubt you'd need these
tiny PCBs to be double sided to get all the traces to the PCB edge, and I
wouldn't be surprised if some commercial usb C leads have PCBs with 4 layers.

I've only designed PCBs myself for the traditional USB PCB mount USB A plug
(an Amphenol part) and Micro B plugs (Hirose ZX series parts) as these are
very simple pinouts and are perfectly doable for a hobbyist I'd say if you
want custom cabling. USB C looks significantly more complex and an in-cable
PCB interface is the only way to go for that level of complexity.

[1]
[https://www.hirose.com/product/en/products/ZX/](https://www.hirose.com/product/en/products/ZX/)

