Wanted: Card Edge Connector: 3.5mm Pitch, 4 Position / 8 Pin, Dual Row - Page 1
Forum section: electronics / general

author: yngndrw
author_rank: Regular Contributor
timestamp: September 23, 2022, 12:47:08 am
content: Hello,I'm looking for a card edge connector: (Ideally through-hole)- 3.5mm Pitch- 4 Position / 8 Pin- Dual Row- 1mm Board ThicknessIt's for a Makita AWS module - The board has 1mm wide slots between each tab, the copper pads are 5mm long and the length of the slot is 7mm.I've attached a picture of the real connector within a tool and a picture of the module which goes into it.I can't find many with this pitch, it almost looks like it has been custom made for the tool.Thanks,-Andrew.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 23, 2022, 01:08:54 am
content: It is custom made

author: yngndrw
author_rank: Regular Contributor
timestamp: September 23, 2022, 01:20:23 am
content: I thought it might be, especially given that it is shaped to fit around the plastic "key" molded into the module.Either way, if there's any connector that would be suitable for the board itself ignoring the plastic portion of the module that would be a big help - Right now I'm having to use a sandwich of custom boards held together with clamps.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 23, 2022, 02:27:03 am
content: you want to interface the makita it seems ... hacking in mindseems to me another way to implement an usb connector ??

author: yngndrw
author_rank: Regular Contributor
timestamp: September 23, 2022, 09:29:24 am
content: No USB ports I'm afraid! I just want to be able to use the Makita AWS system on a non-Makita vacuum, without paying £200 for the Makita adapter (WUT02U) which only works with vacuums which have the socket on the front for automatic triggering. (Which mine doesn't have) Using the Makita AWS modules is convenient as then it will work with all of their tools, I just need to emulate what their adapter is doing. (Which in-turn uses one of the standard AWS modules so I know the modules can operate as either end of the wireless link)

author: coromonadalix
author_rank: Super Contributor
timestamp: September 23, 2022, 10:07:43 am
content: you can design such an pcb connector interface jlcpcb and others ...

author: yngndrw
author_rank: Regular Contributor
timestamp: September 23, 2022, 10:17:44 am
content: I've already designed the board side of it (The green PCBs I showed above) - The problem is the socket so that I can use the pre-existing Makita AWS modules which have that board edge.I may just have to solder wires to one of the modules, I just would have prefered to have used a connector if one was easily available. I suppose I could also 3D print a connector but that's a pain for something which I thought would have been readily available. (Or at least, a compatible edge connector)

author: Gribo
author_rank: Frequent Contributor
timestamp: October 03, 2022, 06:52:42 pm
content: Since it is a custom job, you can use compression terminals and build your own socket. It will make your PCB to PCB connection more reliable. AVX (Kyocera?) has them.

author: yngndrw
author_rank: Regular Contributor
timestamp: October 03, 2022, 11:19:27 pm
content: Thank you, I'll have to have a look at those. It looks like they don't have 3.5mm pitch, but I'll see if I can find some individual ones somewhere.For now I've ended up using a 6/12way connector with a 4mm pitch and a 3D printed adapter to align it which is doing the job for now while I reverse engineer it all. This adapter is working so well that I might just use a 4/8 way version of this connector with an adapter.

author: btb
author_rank: Newbie
timestamp: October 04, 2022, 06:09:18 pm
content: Quote from: yngndrw on October 03, 2022, 11:19:27 pmThat's exactly what I would do. Those 4mm (3.96mm?) (5/32"?) connectors also accept indexing keys in between the contacts if you really need to ensure the alignment without having to 3d print

author: yngndrw
author_rank: Regular Contributor
timestamp: October 05, 2022, 12:03:00 am
content: Ah good idea, I'll have have to have a look at them and see what's available. Thank you.

author: srb1954
author_rank: Super Contributor
timestamp: October 05, 2022, 12:44:28 pm
content: Quote from: yngndrw on September 23, 2022, 12:47:08 am3.5mm is not a standard pitch for an edge connector but you could try looking for 0.150" (3.81mm) pitch edge connectors.Over only 4 pins the difference in the pitch of the edge connector contacts versus the PCB pads would probably be sufficiently small so as not to cause a problem. Using an key in the central slot of the edge connector would centre the connector to minimise alignment errors.

author: yngndrw
author_rank: Regular Contributor
timestamp: October 06, 2022, 11:10:53 am
content: For some reason I seem to be really struggling to find any card edge connectors from the usual suppliers, at least for the smaller pin counts. The only one I've really found is one on Aliexpress which looks mostly like the one I have, so finding keys to fit seems to be difficult.I think my best bet will be to buy the 4/8 way Chinese version of the one I have and 3D print adapters / keys for it, I might be able to design the adapter into the enclosure anyway and it will let me manage the depth as well.

author: Gribo
author_rank: Frequent Contributor
timestamp: October 06, 2022, 01:16:54 pm
content: Will this help?https://www.kyocera-avx.com/products/connectors/board-to-board/low-profile-single-contact-70-9155/

author: srb1954
author_rank: Super Contributor
timestamp: October 06, 2022, 08:29:49 pm
content: Quote from: yngndrw on October 06, 2022, 11:10:53 amBuy a longer one and cut it down to size.

author: yngndrw
author_rank: Regular Contributor
timestamp: October 06, 2022, 10:58:58 pm
content: Quote from: Gribo on October 06, 2022, 01:16:54 pmI think if I were to go down this route I'd need a 90 degree version so that I could use a single PCB for the connectors on both sides - Otherwise I'd have to make some kind of 3D PCB for it out of a few parts which is probably a bit excessive for this project. It looks like they are all flat as they are just meant to connect to one side of a parallel board, like a SIM card etc.Quote from: srb1954 on October 06, 2022, 08:29:49 pmThat's always an option, although if I was doing to go to that trouble I think I might as well just buy the 4/8 pin version of what I have from Aliexpress and then 3D print the adapter for it. I think that sounds like the least effort and I'll just be sure to design it into my enclosure so it can double up as the mechanism to physically support the connector as well.It doesn't have to be perfect anyway as it's just a DIY project so that sounds like a plan. Thank you all for your help.

author: bassicrob
author_rank: Newbie
timestamp: April 01, 2025, 04:56:22 am
content: Quote from: yngndrw on September 23, 2022, 10:17:44 amA bit of a long shot, but do you have any additional information / files you used to create the board interface? I am setting out on the same endeavor, but looking to replace the brand-name transmitter requirement with my own.

author: yngndrw
author_rank: Regular Contributor
timestamp: April 01, 2025, 09:50:02 am
content: Quote from: bassicrob on April 01, 2025, 04:56:22 amI reproduced the fingers as a library component in EasyEDA: (Don't forget to make your PCB 1mm thick)https://easyeda.com/component/595d85b552484409997e1cc43439014cHopefully you can access that and just use it.Here are the notes I had on the pinout:Code:Pins: (From front of chip, top to bottom with the key at the bottom - There are 8 pins, 4 on each side!)Left1 0V 2 NC3 NC4 NCRight1 Trigger  - Module not plugged into tool = 0V, Is pulled high to 5V by the tool when tool activated - When in receive mode the module pulls this to 3V when the pair tool is active2 NC3 Direction  - Module not plugged into tool = 3V, Must be set at start-up - Pulled low via 10k resistor by the tool when inserted which puts it into transmit mode, if left NC it puts it into receive mode4 +5V

author: bassicrob
author_rank: Newbie
timestamp: April 03, 2025, 12:51:08 am
content: This is awesome! I don't have a module but I am looking to interface with the port on the tool, so all my research has been focused on the tool-side. I was assuming:Red = Module 5v PowerBlue= Module GndWhite = Trigger 5vBlack= Trigger GndHowever reading your notes with the communication with the module, I gather that from the tool to a ESP-device all I need is a 3-wire connection, Red, Black, and White. When the module is inserted into the port, I assumed it separates the White / Black Trigger/Gnd connection between the card edge keys?Thanks for sharing the interface PCB layout. This is extremely helpful!

author: yngndrw
author_rank: Regular Contributor
timestamp: April 04, 2025, 07:16:05 pm
content: Yes you won't need the blue connection if you're building a transmit-only module.I'm afraid I don't follow your question about separating the connections.