Tell HN: My phone just told me to check for moisture in the USB port | Hacker News Reader

Tell HN: My phone just told me to check for moisture in the USB port

32 pointsTijdreiziger41 comments

I just spilled some tea on my phone (a Samsung Galaxy S9), and it popped up a notification telling me to check and make sure the USB port is dry before charging.

I didn't know phones did this nowadays. I wanted to share it with HN in case anyone else is surprised by it.

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Get this sometimes on my pixel 4a if I am out and its raining heavily. It also disables the USB until its no longer wet.

I haven't looked into how it works, but I guess it senses a short across some of the pins inside?

Useful feature to prevent the phone cooking itself.

>[...] but I guess it senses a short across some of the pins inside?

Most lithium ion chargers have (or should have) some kind of short circuit protection. It would make sense that the internal charging unit could make this information available to the operating system.

Most USB ports have a chip between it and the host controller for electrostatic discharge (ESD) protection. The nicer ones can also sense shorts and overcurrent on the lines and signal the processor that something is up.

Example: https://www.maximintegrated.com/en/products/power/protection...

Maxim integrated really has a chip for everything

And availability for nobody, even before the pandemic. I always cringe when someone specs Maxim. It's impossible to get eval kits.

My wife was at a meeting, and a friend's kid spilled water all over the table they were sitting at (her phone was sitting on the table). Same thing - Pixel 4a indicated it wouldn't use the USB-C port until water or debris was removed. I used a Q-tip a few hours after the fact (she had cleaned it to the best of her ability), and that seemed to do the trick.

This has been a thing for ages - at least my last couple of phones. I do a lot of outdoor activities, and it's a constant battle to keep the phone dry enough to charge.

In one case, I had gotten into the habit of storing my phone next to my water bottle, which I think caused condensation from the cord temperature, inside the port. A very stressful few days unable to charge.

My iPhone (11) does this every time I shower. I never remember to charge it before.

Got a waterproof phone specifically to listen to podcasts and make notes in the shower so I'll just have to deal with low power mode for a few hours.

.. sometimes a quick blast from an air compressor will sort it, but this is my personal property and I don't advise anyone do anything ever.

If you spend much time at a desk or similar in this situation, get a wireless charger of some kind since that will still work even when the main port does not :)

That's a good shout actually, thank you. I don't think I've ever used wireless charging.

The reason I started using it was similar to yours. I don't take my phone in the shower, but I got the error one day anyway and panicked. I then realized my bedside lamp supposedly had wireless charging and it saved me that day. The problem went away luckily :-)

I gotta know: from the steamy air, or because you take the iPhone into the shower?

The phone sits on the soap holder under the shower head out of the direct stream so both steam and splashes, but the way I position the phone I'd guess it's more the steam than any direct droplets of water (screen faces the wall as the ear/top speaker goes almost silent when water gets on it)

Just curious, how do you listen to podcasts in there with all the shower noise? And how do you type anything on the screen when it's all wet and conductive?

I can barely use an e-reader in a static hot tub, lol, can't imagine actually trying to actively use the phone with a waterfall above my head.

I guess I sort of put together the gist of what the podcast is saying between splashing sounds haha. It's all comedy based stuff that early in the morning so I'm never really missing any required information.

As for typing I'm either writing something short enough the mis-taps aren't too awful to deal with or I'll dictate it. I'm not writing emails or anything, just jotting down quick notes and todo items to expand on later so typos and mis-wording don't matter too much.

I got a version of this alert for the first time on a OnePlus 9 last week whilst using my phone on a long motorcycle trip. It also suggested there might be a foreign object in the port.

Curiously it wasn't raining at the time and had been charging ok for an hour or so. It was the only time I saw this error during the 5,000 km trip - including times when it was raining hard.

Unplugging and replugging the (2 amp) lead did nothing, but leaving it unplugged for ~30 mins seemed to fix it.

I've seen this before and it's a very clever feature. I'm assuming it can detect when there's a complete circuit between two or more pins inside the housing and automatically disconnect it.

I think it's more sophisticated than that. I was getting this message when the humidity was high but there was definitely nothing in the port. I'm guessing it's some sort of capacitive thing because even really humid air shouldn't be able to cause a short unless there is actual condensation.

Phones have been doing this for years. I regularly take my iPhone into the pool and into the ocean. I get that message for a few hours afterwards. Sometimes if I need to charge I will try to dry it out with a hairdryer.

> into the ocean

Do people take their phones into bodies of water? I still worry about mine getting wet when I bring it into the bathroom.

Many kiddos who grew up with very water-resistant electronics seem very casual about submerging their phones... while us oldies who feared a single drop getting into our stuff still worry.

I’m in my 50s but I trust their certification plus I have Applecare! I get a little worried about the salt but I will just assume that apple care will fix anything that goes wrong, although it might have clauses against it. But the underwater photos and videos are fun!

Fellow fiftysomething here who considers AppleCare, like other paid-extended-warranties, a racket.

(If Apple, with all their data, think it's a net-profitable offer, I must be net-losing on the deal versus the default of self-insurance. Especially since I am a more-prudent-than-average device owner!)

I like to go swimming with my phone to take pictures of fish and whatever scary things live at the bottom of alpine lakes...

I wouldn't take it into saltwater though. That doesn't seem great for any exposed contacts... or anything, really, except fish and things that eat fish.

I got this warning on a seemingly dry Pixel 5. It went away in a few minutes.

I got it in an iPhone SE

I get it all the time on my 2020 iPhone SE, even after several hours plugged into the car. I've come to hit "Emergency Override" if I know it's not been around moisture in the last few hours.

Pity, because I wanted to hand this one on to an older relative in a few months, but I'm not about to saddle her with this.

Do you use a third-party (non-Apple) charging cable? That’s usually the cause for this warning.

On the other hand, when I tried to charge my Galaxy S7 with a particular charger (the Surface 3 micro-usb charger), it would tell me there is moisture in the port and refuse to charge.

My Samung a5 of 2017 does that.

Is this missing a 2009 tag?

> I didn't know phones did this nowadays. I wanted to share it with HN in case anyone else is surprised by it.

OPPO invented this when they started deploying VOOC charging (serious current,) standard Android has since copied it.

They measure the resistance in between data pins periodically. If there is no voltage, but resistance is low, they show this alert.

Wonder if it can be used to void warranty like the analogue version - https://en.wikipedia.org/wiki/Liquid_contact_indicator in non water resistant phones

Since the phone is sold as being water resistant, it probably won't be.

> non water resistant phones

iPhones are sold as water resistant, and it’s not covered under the regular warranty: https://support.apple.com/en-us/HT204104

Those LCIs only turn red when water gets inside. On most iPhones these contact indicators appear to be behind the SIM tray.

Not legally in the U.S., but most consumers don't know that.

Reference? (They can seemingly use 'water damage' as excuse to limit what kind of damage is repaired under the warranty, even if it technically isn't completely "voided" – see Apple's support page: https://support.apple.com/en-us/HT204104)

Magnuson Moss Warranty Act.

They have to prove the water caused the issue, not that a sticker got wet. It's like "warranty void if removed" stickers - not legally enforceable.

https://www.ftc.gov/legal-library/browse/statutes/magnuson-m...

https://en.wikipedia.org/wiki/Magnuson%E2%80%93Moss_Warranty...

Water resistant != water proof, there is very big difference.

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