Ribbon Cable for bridging the headers of Raspberry pi and Custom hats

Question

Hello I am in need of a ribbon cable for my custom pi hats. The problem with ordinary ribbon cables such as this

I could not make it to align the rows of the pins will get swapped because of the cable. Here is an image of what it should look like

But in the image it is not obvious that the pins are not being connected the correctly. the Top row pins which is the visible gold pins where the ribbon is attached is actually being connect to the bottom row pins(not visible because of camera angle) of the other end of the ribbon.

I have tried to undo on end of the cable assembly and rotate in all possible combination and attached it back to the cable but still i am not getting proper result?

Any ideas?

Suggestion 2 of this post might help: https://raspberrypi.stackexchange.com/questions/104705/how-to-tap-tee-fork-the-rpi-gpio-pins-covered-blocked-by-a-hat-phat-bo Good luck, cheers. — tlfong01, Jan 13 '20 at 15:11
Why not try a different ribbon? How about this one for $3: https://www.amazon.com/Vaorwne-Breakout-Expansion-Assembled-Raspberry/dp/B082VVDF2Z/ — user96931, Jan 13 '20 at 15:14
@tlfong01 i see i guess there is no way around it i have to make an adaptor board — Jack, Jan 14 '20 at 07:31
@Jack, Ah, but the poor hobbyist has a hobby knife, and a 4" bench vice, :) https://imgur.com/gallery/yJLeJNL. — tlfong01, Jan 14 '20 at 11:43
@Jack, your might be interested: (1) Aligning and Crimping Ribbon Connectors https://www.youtube.com/watch?v=eUcdSSBDEEI
(2) Custom Cables & Guide to Crimping Dupont PCB Interconnect Cables https://www.youtube.com/watch?v=GkbOJSvhCgU — tlfong01, Jan 14 '20 at 12:13
@tlfong01 believe it or not but it is faster for me to do it the pcb way since i already have the components for those. I would have to order the the 10 or 20 gang dupont header, in order for me not to loose my sanity using single ones. I use tweezers and a hammer for undoing the ribbon assembly for mine, I dont even have a vice :D — Jack, Jan 14 '20 at 12:45

score 2 · Accepted Answer · answered Jan 15 '20 at 00:26

It's possible to make what you have work, but I'll warn you from experience it's tedious and time consuming.

Remove the connector (carefully) and cut off the end of your cable taking special care that the cut is perpendicular to the cable.

Using a single-edged razor blade or a knife with a thin, sharp blade, split apart each of the individual wires at the end of the cable for a length of 1 to 1.5 centimeters. Be careful not to expose any of the conductors.

Now, take the second wire of the ribbon cable and cross it over to the first connector position. Gently press the wire into the 'fork' of the connector's contact. You can use needle-nose pliers, but I usually make a tool out of a small diameter hardwood dowel with a slot cut into the end to allow the 'fork' to pass through.

Then take the first wire of the ribbon cable and cross it over to the second contact and press it into that 'fork' as before. Continue this way with the rest of the cable, crossing 3 & 4, 5 & 6, etc. all the way to contacts 39 & 40.

Press the back cover of the connector firmly onto the front until it locks. Cut off any excess cable ends with a razor blade, sharp knife or flush-cut snips. Check all connections for continuity and adjacent shorts before using.

ALSO: Clearly mark this cable so you don't confuse it with a regular straight cable at a later date.

Good Luck!

It actually worked ! this is the cleanest solution so far ! I love the idea, took me 20mins to do it though but nonetheless it worked. No extra modules needed. — Jack, Jan 15 '20 at 05:30

score 1 · Answer 2 · answered Jan 14 '20 at 09:56

It seems that it is not possible with common ribbon assemblies. Instead i just made and an adaptor board as suggested by @tlfong01

This is currently its PCB footprint would look like and would use right angle female headers and ordinary male headers. The ribbon would attach to the male headers and the female headers will go to the bottom of the hat.

score 0 · Answer 3 · answered Jan 13 '20 at 20:50

They way ribbon cables work is this... If you're connecting to the GPIO pins on the Pi, they're on the top of the PCB. A HAT which connects to it has pins on the bottom to mate with the Pi, and they are located to allow this to happen. It's hard to understand from your question, but I'm guessing you're trying to use the ribbon to connect to the female connectors on the bottom of a HAT (perhaps by using a header in between to act as a male-to-male adaptor). The ribbon cable is designed to connect a connector on the top to another on the top - and can't be used to connect a top connector to a bottom one.

Ribbon Cable for bridging the headers of Raspberry pi and Custom hats

3 Answers3