How Are USB Ports Waterproofed in Mobile Devices?

[raminee]

TL;DR

How to water proof a USB port?

Hello All,

I would like to know how mobile devices or EE devices that use mini/micro USB ports are protected from any water contacts ?
i.e. how can you protect against any electrical shorting/damages when such devices are immersed in water ?

R.

 

[berkeman]

USB connectors are not meant for use in water, AFAIK. In fact, my Google Pixel 6 cellphone has a moisture sensor in its USB-C connector that throws an error if the "moisture content" gets too high. (that happened one time when I was working out in the rain for a while)

Why do you want to use standard USB connectors in wet environments? What is the application?

 

[raminee]

I am actually trying to build a wearable product for kids which has a USB connection for charging as well as data connectivity just like many wearable/mobile devices.
We envision that kids are not careful enough and may accidentally get the device wet through rain, just like your own experience, or jump in a pool of water etc and hence I was curious to know how the USB port is protected from water contacting it. I see a lot of iPhones that are recovered from waters such as rivers and they still work well.

With the PCB portion there are water protection resins that one can coat them with but I was not sure how the USB pins get protected as these would have to be uncovered for connectivity with a male USB pin.

 

[berkeman]

I did a Google search on waterproof USB port and got lots of hits. Maybe have a look through the hit list to see if you can find a good candidate for your product:

https://www.google.com/search?client=firefox-b-1-d&q=waterproof+usb+port

Alternately, consider using Bluetooth RF for connectivity and wireless charging...

 

[raminee]

Thank you "Berkeman" !
I already did some research and the two methods that I came across is a cover for the USB and also putting a diode between the power lines on the USB lines. But I was wondering if there are other techniques that they use.

We do have BTLE but adding a wireless charger and a cradle just adds to the cost and complexity of the system. Maybe version 2 !

Cheers

R.

 

[Rive]

adding a wireless charger and a cradle just adds to the cost and complexity of the system

A ready-made wireless charge receiver instead of reliably waterproofing a connector which is not intended to be waterproof may be significantly cheaper and simpler.

Look up 'QI wireless charging receiver'.

 

[rbelli1]

A solution that I have seen on a step tracking watch is that they have metallic spots on the case and use a magnetic cradle with spring pins. Sealing two small pins into a case is way easier than sealing an actual connector system.

The charger for that device is not smart. It burned up when it attracted a paperclip and shorted. Look up how Power Over Ethernet negotiates power to make a safer charger.

BoB

 

[DaveC426913]

My Kobo reader is waterproof. I know, I have pics of me reading it in a pool in Cuba.

It has a watertight rubber seal that you have to pull off to access the port. But if you don't fit it back on, it will surely leak.