IDC connector troubles

Other Hardware General Electronics
1

Hello again,

Hope I'm in the right place, I've been having a lot of trouble with my cable management. I'm driving a bunch of RFID-RC522 sensors from one arduino using SPI, and the cables are an absolute nightmare. I thought that maybe using one long ribbon cable with a few through line connectors would be a good way to tidy everything up, like you see on PC power supplies. I measured my pin pitch (2.54mm) and wire pitch (1.27mm) and took to sites like RS components to try and source some 8-way, 1 row, through-line IDC connectors, and have had zero luck finding any.

Has anyone come across this before? Is there a better way to do what I am attempting? I can find 2 row, 8-way connectors at this size but that doesn't fit the pins on my sensors, unless I can get some sort of adaptor?

This is what my design is based off of, for reference: Escape Room Object Placement Puzzle using Arduino/RFID - YouTube

and this is where I saw ribbon cables being used to connect devices in-line like I envision (under "pro-ing up our cables"): An Introduction To Differential I²C | Hackaday

2

SPI is designed for on-board inter-chip comms, not over a long cable. Long cables really need line drivers and termination at both ends to carry fast logic signals.

All IDC plugs can be daisy chained trivially. Why do you think they can't? IDC connectors are 2 row, not 1 row.

3

For the connectors check out Samtec they make connectors with the following specifications.
.100" (2.54 mm) pitch
Most common pin counts from 5 to 20
Dual beam contacts mate with .025" (0.635 mm) square posts
Wide variety of wiring options including reverses, daisy chains, etc.
Gray and color coded cable
Mating shrouded terminal strips and ejector headers
Polarization key
This looks like it might work for your connector. I have no idea what a bunch of sensors are but within reason and on the same board the SPI should work just fine. If you wire it as shown in the you tube it will fail, the star configuration causes a lot of impedance mismatch. Your example shows daisy chaining with ribbon cable that should work much better. Place ground wires on each side of the clock signal. You need to terminate it and not run it any faster then needed. As stated in your second link you can go to a differential line driver, that will work very well with longer wires. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
Gil

4

Dupont connectors are SIL and come in 8 way. I had all mine in a kit from "Preciva".