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I'm looking to connect 2 small PCBs. I have up to 10 signals that need to be passed from 1 PCB to the other. The 2 PCBs sit perpendicular to each other, and need to be detachable; 1 PCB is an 8 layer, while the other can be anything (doesn't exist yet). Consumer device, so the speed of the signal and all that can be neglected for now; as long as the 2 boards are electrically connected and can be disconnected, it is okay.

The easiest solution would be to use an edge card connector. However, I have less than 6.5mm in width, and need the height to be minimal. I was thinking some gimmicky way to use slots in order to connect the PCBs in a puzzle like fashion, but I feel the connectivity reliability would be questionable.

I'm open to any crazy ideas; or if anyone has found really small connectors, or done something similar, please feel free to share your experience.

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  • \$\begingroup\$ would you be comfortable if the mechanical support between both board is actually provided by a mechanical piece rather than the connector itself? \$\endgroup\$ – Simon Marcoux May 9 '18 at 17:43
  • \$\begingroup\$ @SimonMarcoux as long as its small (we have basically wiggle room to implement this), I don't see why not. \$\endgroup\$ – user188315 May 9 '18 at 17:45
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    \$\begingroup\$ Can you use a flex circuit for the 2nd one? \$\endgroup\$ – Spehro Pefhany May 9 '18 at 17:46
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    \$\begingroup\$ How many times will these boards be mated & unmated throughout the life of the device? \$\endgroup\$ – Nick Alexeev May 9 '18 at 17:48
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    \$\begingroup\$ There are literally thousands of right-angle board-to-board connector systems already on the market. You'll have to be a lot more specific about your space constraints before we can narrow it down, and product recommendations are off-topic here anyway. (I happen to like the products from Samtec, FWIW.) \$\endgroup\$ – Dave Tweed May 9 '18 at 18:20
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Consider using a flex circuit

FH12A-12S-0.5SH(55) with 12 pins is one I'm using now. This series has 0.5mm pitch.. 10 pins is less than 10mm long even with the end hinges.

You need to specify the FPC with a stiffener that meets the connector thickness requirement and to make the shape tolerances compatible, other than that it's pretty painless.

The lever cover makes connecting a snap.

enter image description here

There are vertical types too.

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My outside of the box solution is to 3d print a corner shaped extrusion that will mate both boards together mechanically without any electrical connection. The extrusion would roughly look like this (disregard the dimensions!): enter image description here

Once both boards are physically attached to each other. You can use a flat ribbon cable with connectors on both board and run it along the corner line. My recommendation would be to use the exact same connectors than a raspberry pi camera/display. You can easily source them and the equivalent cable. Furthermore, they provide you with 15 different conductors on it to give you some headroom for future improvements. The connector can be roughly anywhere on the board provided that it is oriented properly and that there are no huge components in the path.

Picture of the connector that I'm referring to:enter image description here

The key advantage that I see at the end of the day is that you don't rely on your connector for mechanical support. You can even adjust the support length if components are in the way (two sub sections instead of running the whole length.

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  • \$\begingroup\$ Because as we all know 3D printing can do anything, I will note that you can get conductive carbon loaded filament. You could alternate conductive and insulating filament to make this shape a 3D printed anisotropic connector. a la zebra strip. \$\endgroup\$ – Henry Crun May 9 '18 at 20:50
  • \$\begingroup\$ I love the way dev boards use the smallest possible components mounted on the most extravagantly enormous PCBs imaginable. \$\endgroup\$ – Wossname May 9 '18 at 21:26
  • \$\begingroup\$ @Wossname now that you mention it! I never pondered on that fact before. I merely saw them for their educationnal value and ease of usage. \$\endgroup\$ – Simon Marcoux May 10 '18 at 0:52
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JMC connectors could work. The 20 pin version is 7.9mm wide. Stacked height is 5.6mm.

enter image description here

http://www.jst-mfg.com/product/pdf/eng/eJMC.pdf

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  • \$\begingroup\$ I apologize, I included the wrong measurement. Width of <6.5mm is needed to make things less complicated. \$\endgroup\$ – user188315 May 9 '18 at 18:09
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Machined pin connectors let you make an ad-hoc connector design, which you can sneak into small spaces, and are very reliable

You can drop the sockets through the board, you can put them sideways into slots in the pcb, you can solder them laying flat on the surface etc etc.

You can use them with or without the plastic, and you never have to try and find a connector with the right number of pins.

See the Mill-Max website

enter image description hereenter image description here

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