Button design on PCB

Questions relating to designing PCBs

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Malber
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Joined: Thu Nov 17, 2016 1:06 pm

Button design on PCB

Post by Malber » Thu Nov 17, 2016 2:38 pm

Hello
I am relatively new to PCB design and am currently designing a simple circuit for a bike light. The LED's will be controlled by a PIC12 which will have an input from some kind of button. My immediate idea was to use a regular tactile switch for the button, but from looking at a range of different electronics it seems to me that some kind of a silicone key (similar to those used here https://learn.sparkfun.com/tutorials/bu ... okup-guide also see img below) is more widely used. I have been unsuccessful in my attempt to find out how to do these. So my question is then, how do I integrate these into my PCB design? Can I do the contact areas with regular open copper pads, or does it need to be covered by gold or similar? Also, how would I draw the footprint (I'm using Eagle)?

Thanks in advance :)

Image

lyndon
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Location: Minnesota, USA

Re: Button design on PCB

Post by lyndon » Sat Nov 19, 2016 10:40 am

Those switches are used because when you're making a million units, they are much cheaper. For your application it's probably simpler to use a low-profile tactile switch.

Malber
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Joined: Thu Nov 17, 2016 1:06 pm

Re: Button design on PCB

Post by Malber » Mon Nov 21, 2016 1:07 pm

Thanks for the reply. That does make sense, but how do make those sealed so that I am not getting water into my electronics when the light is in use. I haven't been able to find a cap that seems to create a seal.

mattylad
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Joined: Sat Sep 25, 2010 3:49 pm

Re: Button design on PCB

Post by mattylad » Fri Nov 25, 2016 12:54 am

What sort of enclosure are you going to use?

If you use something like a B3F\B3S switch that comes close to the level of the surface of the enclosure top and you have say an 8mm (ish) hole in the enclosure lid, then a plastic stick on label over the top - then you can push onto that to use the button and it should be relatively water resistant.

If your going for "waterproof" (can be submerged in water) then you would need to look for waterproof switches.

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