How do I make this gadget waterproof?

Hi all!

I'm developing an electronic application which looks more or less like the picture. Diameter abt 40 mm. I need to find a way to make this waterproof, at least down to 5 meters. Another requirement is that the 2 knobs need to have a tight wrap around them (they are tactile switches), which means that I can't just put it in a waterproof plastic bag.

I have looked into shrink wrapping, which would make the 2 knobs stick out like I want, but I have understood that the seals in a shrink wrapped product are usually not too watertight.

I would also like a wrapping that gives a smooth upper surface, if this is possible.

Maybe shrink wrap and watertight tape over the bottom seal would work? Can you think of other ways to do it?
Thanks in advance!

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Downunder35m9 months ago

Casting the electronics in resin is the usual way in the industry.
And if combine with waterproof switches like a reed contact and sliding magnet the depth of the water does not matter much anymore...

karolina81 (author)  Downunder35m9 months ago

Thanks, I didn't know this! But what if the resin is elastic, couldn't I also cover the switches with it?

Only works for limited exposure as the water pressure will either weaken the seal or activate the switches.
But you can use designs enclosed in the resin like pushrods with a spring.
Once you push the rod in it closes two contact rings so all electrical stuff is still protected.
Of course you would bee rubber rings too to prevent the water from going in when pushing....

iceng9 months ago

There are Zero Boxes and Zero Cases that can go that deep

Zero Box.jpeg
iceng iceng9 months ago

Oh, and they have a vacuum pressure release screw so it can be opened.

iceng iceng9 months ago

You do know they come in smaller sizes and as Downunder points out magnets can work reed switches from milliamps to 1amp even SPDT inside...