Access to GPIO connector in a Flirc Case

[pfletch101]

I have my Pi 4b-4 in a Flirc Case, which solves the heating issue which the Pi 4 otherwise suffers from. However, at some time in the future, I will probably want access to the board's GPIO connections, and this is proving a bit challenging. The Flirc case has a narrow cutout in its base positioned so as to allow a ribbon cable from the GPIO pins to exit there, but I have found that the ends of the connector of a standard 40-pin ribbon cable, when it is plugged in to the GPIO pins, foul the mounting pillars for the top of the case, so you can't close the case. I have tried a couple of different cables that I have around, with consistent (negative) results. I imagine that there would be the same issue with the 3b and 3b+ boards in a Flirc case. Does anyone have a source for unusually narrow ribbon connectors that can fit between the pillars?

[LTolledo]

I confirm this on the RPi3B+ version of the FLIRC case (just took mine from storage to verify pfletch101's concern)

in my measurement, the 40-pin ribbon connector's length is about 55.5mm (correct me on this), while the pillar to pillar widest distance is 53mm so definitely a 40-pin ribbon connector's 55.5mm will not fit.

it may be a "stupid idea" but have you tried filing the sides of the ribbon connectors to reduce the overall length?

well checking again the ribbon pin1-to-pin40 distance is about 51mm (again you may correct me on this)
you'll probably need to file it down to 52mm in order to have the cable fit to narrowest top part of the pillars, but this is not recommended as it will surely weaken the connector.

maybe the GPIO access port was designed with single or ganged dupont jumpers in mind, and not the regular ribbon connectors
how about making a 40-pin GPIO ribbon cable out of ganged dupont jumpers?

[pfletch101]

I confirm this on the RPi3B+ version of the FLIRC case (just took mine from storage to verify pfletch101's concern)

in my measurement, the 40-pin ribbon connector's length is about 55.5mm (correct me on this), while the pillar to pillar widest distance is 53mm so definitely a 40-pin ribbon connector's 55.5mm will not fit.

it may be a "stupid idea" but have you tried filing the sides of the ribbon connectors to reduce the overall length?

well checking again the ribbon pin1-to-pin40 distance is about 51mm (again you may correct me on this)
you'll probably need to file it down to 52mm in order to have the cable fit to narrowest top part of the pillars, but this is not recommended as it will surely weaken the connector.

I used to make my own ribbon hookups for IDE drives, since this allowed me to use the exact length of cable that fitted best for a given case/motherboard/drive location combination - improving both access and cooling. The connectors I used then, and the ones that seem to have been used on the commercial ribbon cables I have now, come in two parts which are clamped together over the cable and held together by clips on both ends of the connector. Almost any 'filing down' will damage or destroy these clips, and the connector will then come apart and lose contact with the cable wires with minimal disturbance. For a connector to work with the Flirc case, I think that it would need to be moulded on to the wire, with little or no overlap at the ends. I haven't seen anything like this available.

maybe the GPIO access port was designed with single or ganged dupont jumpers in mind, and not the regular ribbon connectors
how about making a 40-pin GPIO ribbon cable out of ganged dupont jumpers?

I think that this might be the only other approach that might work, The wires come out of the ends of the dupont jumper connectors, rather than the sides (which would be preferable), but I think that there would be room to loop the cables round. Anyone know the heat tolerance of the insulation on dupont cables?

[jj_0]

There's a FAQ on the Flirc RPi 4 case page where question 9 specifically adresses the gpio ribbon cable issue:

I'm having trouble fitting a standard IO Cable for the Connectors, do you have a recommendation?
Yes, this one works perfectly fine: https://octopart.com/search?q=IDSD-20-D-06.00

I haven't tried it myself, if you do please let us know if it fits.

[pfletch101]

There's a FAQ on the Flirc RPi 4 case page where question 9 specifically adresses the gpio ribbon cable issue:

I'm having trouble fitting a standard IO Cable for the Connectors, do you have a recommendation?
Yes, this one works perfectly fine: https://octopart.com/search?q=IDSD-20-D-06.00

I haven't tried it myself, if you do please let us know if it fits.

I now see the FAQ entry, but the link points to a page with a table with multiple cables listed. The connectors on all the ones which have images look like (i.e. seem to stick out as much as) those on the cables I have, and the specs do not include connector width. I am not really inclined to buy a cable 'on spec' without more reason to think it really is different. I have left a message about this on the Flirc site, and will post their response in due course.

[LTolledo]

did the math on the linked "slim connector", it turned out as 52.3mm

it will probably be a tight fit on the narrow end of the pillars....

[Imperf3kt]

What about something like this
https://www.mouser.com/ProductDetail/TE ... z7Ehuec%3D

Found by googling "2x20 2.54 female"

You'd have to attach your own wires, but the connection itself is very slim.

[pfletch101]

What about something like this
https://www.mouser.com/ProductDetail/TE ... z7Ehuec%3D

Found by googling "2x20 2.54 female"

You'd have to attach your own wires, but the connection itself is very slim.

That looks like a ganged connector for Dupont cables, and should, indeed, work. I would rather have something that doesn't need wires crimping/soldering, but will keep it in mind.

[jj_0]

did the math on the linked "slim connector", it turned out as 52.3mm

it will probably be a tight fit on the narrow end of the pillars....

I tried the math (No. Positions/row x (2.54) .100 + (1.50) .059) as well even though I don't quite understand the (2.54).100 nor (1.50).059 in the formula, I got to 52.459

But the cable I would want would be a IDMD-20-T-06.00 so female header one end, male header other end, double row of 20 positions for each header, 6 inch cable length. Farnell doesn't specify the connector width, but it looks pretty slim at each end on the picture. Unfortunately the picture has a disclaimer on it...

[LTolledo]

the values inside the parenthesis are the ones to use for metric, the ones outside are for imperial/inch.

[LTolledo]

What about something like this
https://www.mouser.com/ProductDetail/TE ... z7Ehuec%3D

this is about 53.34mm according to the data sheet. ([ {40/2} x 2.54 ] + [1.27 x 2] )
still might be tighter fit on the narrow side of the pillars, and will need some sort of filing...

[jj_0]

the values inside the parenthesis are the ones to use for metric, the ones outside are for imperial/inch.

Thanks! I get it now.

[pfletch101]

There's a FAQ on the Flirc RPi 4 case page where question 9 specifically adresses the gpio ribbon cable issue:

I'm having trouble fitting a standard IO Cable for the Connectors, do you have a recommendation?
Yes, this one works perfectly fine: https://octopart.com/search?q=IDSD-20-D-06.00

I haven't tried it myself, if you do please let us know if it fits.

I now see the FAQ entry, but the link points to a page with a table with multiple cables listed. The connectors on all the ones which have images look like (i.e. seem to stick out as much as) those on the cables I have, and the specs do not include connector width. I am not really inclined to buy a cable 'on spec' without more reason to think it really is different. I have left a message about this on the Flirc site, and will post their response in due course.

I got a reply from Flirc which reassured me that these cables really do fit, so I bought one, and it does. There are multiple cables on the linked page, which differ mainly in how their connectors are oriented, but they all have the same narrow connectors.

[jj_0]

There's a FAQ on the Flirc RPi 4 case page where question 9 specifically adresses the gpio ribbon cable issue:


I haven't tried it myself, if you do please let us know if it fits.

I now see the FAQ entry, but the link points to a page with a table with multiple cables listed. The connectors on all the ones which have images look like (i.e. seem to stick out as much as) those on the cables I have, and the specs do not include connector width. I am not really inclined to buy a cable 'on spec' without more reason to think it really is different. I have left a message about this on the Flirc site, and will post their response in due course.

I got a reply from Flirc which reassured me that these cables really do fit, so I bought one, and it does. There are multiple cables on the linked page, which differ mainly in how their connectors are oriented, but they all have the same narrow connectors.

Thanks for confirming this! I ordered one myself but it hasn't arrived yet.

[MisterEd]

I ordered one of these cables myself from Digi-Key on August 22 and finally got it today September 9. It took this long because it was a special order item.

My requirements were female connectors on both ends and a length of 8 inches instead of 6 inches
Samtec # IDSD-20-D-08-00
Digi-Key #: IDSD-20-D-08-00-ND

I am using the cable with my Pi 3B+. I have a breadboard for it. If it works out I will order another one for my Pi 4 in its Flirc case.

[rangioran]

pfletch101,

You say that you got one of the Octopart ribbon cable GPIO extender cable to suit a Pi 4 in a Flirc case? I'm looking for the female to male type but struggling to identify it from the Octopart product list - if you got the male to female sort, what type number was yours?

[pfletch101]

pfletch101,

You say that you got one of the Octopart ribbon cable GPIO extender cable to suit a Pi 4 in a Flirc case? I'm looking for the female to male type but struggling to identify it from the Octopart product list - if you got the male to female sort, what type number was yours?

I'm afraid that I can't help - I got a female to female one and I don't recall seeing female to male connectors listed (or I might have bought one).

[rangioran]

pfletch101,

You say that you got one of the Octopart ribbon cable GPIO extender cable to suit a Pi 4 in a Flirc case? I'm looking for the female to male type but struggling to identify it from the Octopart product list - if you got the male to female sort, what type number was yours?

I'm afraid that I can't help - I got a female to female one and I don't recall seeing female to male connectors listed (or I might have bought one).

Thanks anyway