How does my cellphone detect moisture in its USB port?

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In summary, a cellphone detects moisture in its USB port through the use of moisture sensors that are integrated into the device. These sensors often consist of conductive materials that can identify the presence of water by measuring changes in electrical conductivity. When moisture is detected, the phone may trigger alerts to prevent damage, disable charging functions, and prompt users to dry the port before further use. This feature helps protect the internal components of the device from corrosion and malfunction.
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berkeman
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I had a shift outdoors yesterday where it was raining off and on. I was mostly under EZ-Up tents, but was out in the rain a little and there was plenty of moisture blowing in the air from the foggy conditions.

Part-way through the day, after the rain had let up for a few minutes, I happened to see a notice on my Google Pixel 6 cellphone similar to this one:

1698081064518.png

https://candid.technology/liquid-or-debris-in-usb-port-pixel/

I'd never seen something like that before (and was happy that it was reporting that all was okay), but it got me wondering how the phone can detect when some moisture gets into the type-C USB port. Does it look at leakage current between the 5V and Ground pins, or some other characteristic between the other lines in the type-C connector? I've worked mostly with circuitry for type-A and micro-USB connectors, and not so much with type-C, so maybe this is a feature of type-C only?

1698081313064.png

https://medium.com/@leung.benson/usb-type-c-s-configuration-channel-31e08047677d

Thanks for any insights. :smile:
 
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  • #2
I think there's a moisture sensor in the port. Per Samsung:

Devices with a waterproof rating of IP68 and above (most of the Galaxy series) are equipped with a moisture detection sensor to prevent water damage to the device.

I assume the same is true for other brands.
 
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  • #3
Oh, that's an easy one.
Your phone is powered by the magic of electricity! It's a little known fact that water conducts electricity!

Follow me for more pro-tips.[EDIT: OK, Drakkith's answer may be more useful.]
 
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  • #4
LOL goofball Dave. :smile:
 
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Drakkith said:
I think there's a moisture sensor in the port. Per Samsung:

Devices with a waterproof rating of IP68 and above (most of the Galaxy series) are equipped with a moisture detection sensor to prevent water damage to the device.

I assume the same is true for other brands.
Thanks Drak. Link?
 
  • #7
Drakkith said:
Here you are.
Fantastic! Thanks Drak. So it's not a feature that is built-in with generic USB-C ports, but an additional detection device in the USB-C port of these devices. Cool stuff. :smile:
 
  • #8
That is my understanding, yes.
 
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  • #9
It must be an impedance measurement between the pins, since it recovers quickly. Other sensors (magnetoresistive, etc.) take longer to recover. They are also an extra part to add into a tight space. An integrated microcontroller could do the impedance measurement.

Phones also have permanent sensors for warranty purposes, both visual and electronic.
https://appleinsider.com/articles/1...ove_water_sensors_for_detecting_iphone_damage
 
  • #11
berkeman said:
That patent seems more to be for water intrusion into the interior, rather than moisture entry into the USB connector, no?
yes, exactly. A one time thing.
You won't find anything from Apple about impedance measurement, it's as old as vacuum tubes.

Which reminds me of a marketing guy that wanted me to patent a different, but similar, thing for lasers. I laughed and told him I stole it from a guy, who stole it from another guy, who copied it from a book, etc...
 
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  • #12
berkeman said:
Fantastic! Thanks Drak. So it's not a feature that is built-in with generic USB-C ports, but an additional detection device in the USB-C port of these devices. Cool stuff. :smile:
It shows what they can do when they want to. BUTTTTTT how come they don't slow down the processor when my iPhone gets nearly hot enough to burn my leg?
 
  • #13
sophiecentaur said:
BUTTTTTT how come they don't slow down the processor when my iPhone gets nearly hot enough to burn my leg?
It's doing updates or something. There was a piece in the news in the last week or two...
 
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  • #15
Hmm. If I’m clever enough to take all the measures they describe then so is my iPhone. Power dissipation is as much related to clock speed as anything and the stupid machine could warn me about heavy use.
The annoying thing is that it feels like thermal runaway. No excuse imo.
 
  • #16
Especially if you keep it in your front pocket... Yeowie!
 
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FAQ: How does my cellphone detect moisture in its USB port?

How does my cellphone detect moisture in its USB port?

Cellphones detect moisture in the USB port using sensors that measure the electrical conductivity of the port. When moisture is present, it changes the electrical properties, triggering the sensor to alert the user.

What type of sensors are used to detect moisture in the USB port?

Capacitive or resistive sensors are commonly used to detect moisture. These sensors can detect changes in capacitance or resistance caused by the presence of water or other conductive liquids.

What happens when moisture is detected in the USB port?

When moisture is detected, the phone typically displays a warning message and disables charging or data transfer to prevent damage to the device and ensure user safety.

Can moisture detection sensors in USB ports be triggered by other substances?

Yes, these sensors can sometimes be triggered by other conductive substances such as sweat, oils, or certain chemicals, which can alter the electrical properties of the port similarly to water.

How can I safely remove moisture from my phone's USB port?

To safely remove moisture, you can gently shake the phone to dislodge water, use a dry cloth to wipe the port, or let the phone sit in a dry, ventilated area. Avoid using heat sources like hair dryers, as they can damage the phone.

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