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I'm designing a handheld device that has just a few buttons that will make some configuration changes. (Very much like a game controller) I'm currently making a set of 3 prototypes - a production run if any will be less than 25 units.

I want to use a SMT tactile switch on a small pcb and a switch cap that I'll have made (machined out of Delrin or 3D printed). The enclosure (plastic or a thin aluminum sheet) will have holes for the switch caps.

Why type of membrane should I used to make the enclosure watertight (to IP67)?

How do I shield for EMC?

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  • \$\begingroup\$ Unless you are making some cloaking military equipment, I think a push button can't produce such EMI. \$\endgroup\$ – Marko Buršič Jan 12 '18 at 21:02
  • \$\begingroup\$ The inside of my enclosure is shielded (electrically-conductive nickel coating) and the plastic switch cap is a hole in my shield to the outside world. \$\endgroup\$ – D Duck Jan 12 '18 at 21:07
  • \$\begingroup\$ "Watertight" is a very vague term... Is that coffee spill proof, drop in the toidy for 10 seconds, rain-proof, drop in the bottom of the harbor.... It's also the bigger of your two issues. \$\endgroup\$ – Trevor_G Jan 12 '18 at 21:15
  • \$\begingroup\$ IP67. Protected from dust and capable of withstanding water immersion between 15 cm and 1 meter for 30 minutes. \$\endgroup\$ – D Duck Jan 12 '18 at 21:19
  • \$\begingroup\$ IMO membrane switches are water-resistant, if not waterproof when correctly glued. Maybe add some extra glue for better sealing. If it's not good, then look how waterproof switches are done. \$\endgroup\$ – Fredled Jan 12 '18 at 21:29
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IP67 seal is not easy :) Maybe a silicon keypad with the gasketing built into the part? Then just have to design your enclosure to compress it. Or epoxy it in place.

They make stock ip67 tact switches that are rather large. Most IP rated products are bigger than say the button on an X-box controller.

Again the problem comes down to then sealing that button to your enclosure with o-rings or epoxy. Depends what you're making.

If you really end up having an EMI problem and you used silicon switches you could probably put some flexible emi foam or gasket around it if you had to. That's starting to get fancy though, your all metal case with some small holes in might be fine.

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  • \$\begingroup\$ Olympus stylus tough TG-5/Nikon Coolpix W300/Lumix FT5/Canon PowerShot D30 are all waterproof digital cameras with size and style of buttons I'm looking for. \$\endgroup\$ – D Duck Jan 12 '18 at 22:19
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    \$\begingroup\$ Yep and I'd bet they made those as custom parts. Consumer Camera buttons aren't off the shelf although sometimes you will find little tact switches below what looks like a button to the user. So if you have the funds you can do something similar. Make a custom sealable top and use any standard tact switch that you like. \$\endgroup\$ – Some Hardware Guy Jan 12 '18 at 22:46
  • \$\begingroup\$ You can 3d print silicone(3dprint.com/88316/wacker-3d-printed-silicone) rubber parts. Has anyone printed a button that looks like the this link and interacts with a [standard(na.industrial.panasonic.com/products/electromechanical/switches/…) tactile switch. \$\endgroup\$ – D Duck Jan 13 '18 at 10:46
  • \$\begingroup\$ I'm not 100% sure that waterproof is that difficult - soft drink plastic bottles are everywhere, pretty watertight, very low cost and the contents are even under pressure! \$\endgroup\$ – D Duck Jan 27 '18 at 13:43
  • \$\begingroup\$ Yeah got any connectors, switches, or wires coming out of those soft drink bottles? \$\endgroup\$ – Some Hardware Guy Jan 27 '18 at 13:44

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