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I want to realize i2c communication myself using Raspberry Pi and a LCD module. I am reading documentations to find an appropriate connector but I am a bit confused and I need help.

Here is the LCD module that I want to use.
https://www.digikey.com/product-detail/en/COG-C144MVGI-08/153-1146-ND/2523706
Data sheet : https://media.digikey.com/pdf/Data%20Sheets/Varitronix%20PDFs/COG-C144MVGI-08.pdf

Here is the connector that I found :
https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/A9CAG-1202F/A9CAG-1202F-ND/470099

http://www.johnsonelectric.com/en/resources-for-engineers/ffc-flat-flexible-cables/ffc-inquiry-form-and-distribution-availability/~/media/68341462F8C24422B092CABF67385811.ashx
(The FFC used is PSR1635-12.)

Are they compatible? The pitch is 0.100", so that should be find, but I am not exactly sure if the cable width corresponds to that of the LCD module. I want to solder the LCD module and the connector so that I can use it more easily afterward. Thank you.

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  • \$\begingroup\$ The LCD seems to have 0.8 mm pitch flex cable. Your cable has 0.100" (2.54mm) pitch. Also, it is not clear if LCD end is solderable. \$\endgroup\$ – Ale..chenski Jul 25 '18 at 23:26
  • \$\begingroup\$ @AliChen Maybe I misunderstood. Does pitch signifies "pin width + spacing width"? \$\endgroup\$ – user167987 Jul 25 '18 at 23:32
  • \$\begingroup\$ "pitch" is the center-to-center spacing of the pins. \$\endgroup\$ – Peter Bennett Jul 26 '18 at 0:18
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The connector on LCD module is FPC, which is "flexible printed circuit". It is possible, although quite cumbersome, to solder FFC (flat flex cable) to FPC. However the end result will be fragile and FPC can be damaged with time.

I would suggest making PCB board with 12 pads 0.5mm wide, spaced 0.3mm apart. The pads will spread to 0.1" holes which you can use either to solder that cable or to populate with pin header to be mated with the header on the cable. Something similar to this but with single row of 12 holes:

enter image description here

Ideally the PCB should be big enough so it can be attached to the back of LCD with thick and soft double-sided mounting tape. This will minimize strain on FPC.

UPDATE

Actually, digikey has suitable board in their catalog, but no inventory available. Here it is directly from proto-advantage

enter image description here

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  • \$\begingroup\$ See an update. You might find something like that from suppliers other than digikey. \$\endgroup\$ – Maple Jul 25 '18 at 23:52
  • \$\begingroup\$ You can probably use a board with the right pitch and too many pins at the cost of not having a mounting pad to solder one end of the connector. Or you can use a connector with too many pins at the cost of having to insert the ribbon carefully. \$\endgroup\$ – Chris Stratton Jul 26 '18 at 0:27
  • \$\begingroup\$ The FPC on the LCD is too wide to fit into clamshell connector with less then 28 pins. Besides it is designed to be soldered. The suggested SMT adapter can be populated with exactly 12 pins, or can be soldered to 12-conduit FFC. In both cases there are no "costs" that you describe. \$\endgroup\$ – Maple Jul 26 '18 at 0:50
  • \$\begingroup\$ @Maple Again, I am very grateful for the detailed advice. Now I fully understands what to do. \$\endgroup\$ – user167987 Jul 26 '18 at 1:46

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