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Novel PCB/Flex Stackup

A project log for KAN-15 LED Tactile Switch

A satisfying clickity on/off switch for your PCB projects

JeremyJeremy 10/12/2020 at 08:203 Comments

A couple weeks ago I was struggling to get to sleep while my head was wrapped around this problem: in order to create an LED breakout board for this switch, you would need to create a pretty thick stackup: 3D printed spacer ( 0.8mm) + PCB (1.6mm) + switch (7mm) = 9mm (3/8 inch). Not to mention that it requires you to own a 3D printer.

Then, it occurred to me. Thin PCB spacer (0.8mm) + flex PCB (0.1mm) bottom.

Layers:

This should create a very thin stack and allow the LED to shine through the bottom of the switch well.

To assist with lining up the layers and holding them together, there are matching  round solder pads on the sides of the PCB/Flex which connect (perhaps unnecessary). 

I'm waiting on an order from OSH park with the new parts and will post an update when I get them.

PCB Files

You can download all the PCB files in KiCad format from this new github repository:

https://github.com/jgillick/KAN15

Discussions

gecko242 wrote 10/12/2020 at 15:22 point

Any reason why you would not just use reverse-firing SMD LED's with a hole through the board?

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Jeremy wrote 10/12/2020 at 21:51 point

That's totally possible and something I'm planning to explore again. This time around I was looking for something entirely encapsulated, without parts mounted on the bottom side.

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gecko242 wrote 10/13/2020 at 08:30 point

Makes sense! I have always wanted to see if I could embed LED's inside a pcb with a plated slot... 

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