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I'm trying to build a waterproof controller to mount on a motorcycle, to interact with a Raspberry PI Zero. I'm looking for the best way to build something flat (it has to be mounted on the handlebar), sort of like this controller for heated grips:

enter image description here

https://sep.yimg.com/ay/yhst-11545572856523/oxford-heaterz-premium-sports-heated-grips-28.png

I'm thinking about a PCB with small push buttons (the surface mounted ones), but what I'm struggling with is finding those rubber caps to go on top of the switches. Do they exist for consumer sale, and if yes what are they called? Can anyone recommend a better method?

Cheers

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  • \$\begingroup\$ (1) Are you sure that the controller in the picture has got rubber caps? To me, the front panel looks like a label with built-in membrane switches and LEDs. Of course, I only have picture to go by. Membrane switches like that are custom. I've never seen an off-the-shelf one. (2) If you want to find waterproof hardware, you should search by ingress protection rating (IP code). \$\endgroup\$
    – Nick Alexeev
    Oct 7, 2018 at 0:48
  • \$\begingroup\$ Rubber caps are used there. Likely silicone conductive rubber switches, like a remote. \$\endgroup\$
    – Passerby
    Oct 7, 2018 at 0:59
  • \$\begingroup\$ found this dyna-graphics.com/… \$\endgroup\$
    – jsotola
    Oct 7, 2018 at 1:02
  • \$\begingroup\$ @NickAlexeev, I've looked up membrane switches and I've found a few for sale, but it seems a bit impractical and expensive to use them. \$\endgroup\$
    – GCannizzaro
    Nov 15, 2018 at 21:56
  • \$\begingroup\$ @Passerby, looked those up too, seem to have the same implementation complications and cost of the membrane switches. \$\endgroup\$
    – GCannizzaro
    Nov 15, 2018 at 21:56

2 Answers 2

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Unless you have designed and tested an IP67 or IP68 enclosure before, moisture has a way of getting thru plastic seals with vapour pressure and many plastic coatings are hydroscopic. Neoprene and rubber are good gaskets for covering the entire keyboard board and double O-ring seals are commonly used in compression cases.

These are some design criteria to keep in mind.

 To be waterproof, a membrane switch must:   
•   Be completely water resistant even in full submersion.  
•   Utilize an edge gasket between the overlay edge and mounting case.  
•   Be durable enough to ensure longevity.   
•   Use specific materials that prevent damage from extreme weather or temperatures.  
•   Have circuits and wire entry vapour pressure isolated from outside environments.   
•   Be simple to install or retrofit into existing equipment.
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Having researched different solutions based on the answers above, I think a solution might be to ditch the flatness requirement in favour of a handlebar mounted button enclosure like this:

enter image description here They are extremely cheap on eBay and should be able to accommodate standard waterproof momentary switches. I'll try to replace the existing ones and seal the backs (inside) with silicone.

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