USB "Condom" Allows You To Practice Safe Charging

MojoKid writes "Yep, a USB condom. That term is mostly a dose of marketing brilliance, which is to say that grabs your attention while also serving as an apt description of the product. A little company called int3.cc has developed a product—a USB condom—that blocks the data pins in your USB device while leaving the power pins free. Thus, any time you need to plug a device such as a smartphones into a USB port to charge it—let's say at a public charging kiosk or a coworker's computer--you don't have to worry about compromising any data or contracting some nasty malware. It's one of those simple solutions that seems so obvious once someone came up with it."

Comments

Re:*yawn* these have around for years?

[Anonymous Coward]

The host power lines are usually protected by a "polyfuse" (aka self-resetting fuse), sometimes just one for all lines combined if the total current is no danger to the traces should it be drawn from one port. A polyfuse is a (normally small) resistance which is designed to go into thermal runaway when the current limit is exceeded. After a few minutes without current, the fuse "resets", i.e. it cools down sufficiently for the resistance to drop far enough that the normal current won't trigger the thermal runaway.

Re:*yawn* these have around for years?

[AmiMoJo]

Actually there is a standard, laid out in the USB Battery Charging Specification. It clearly states that a dumb charger should short D+ and D- directly to indicate that it can supply up to 1.5A.

The only company that uses resistors is Apple. The USB spec was released in 2007 so maybe their early devices pre-dated that. In any case, any properly designed USB device from the past 5 years should fast charge from a dumb charger simply by having the D+ and D- lines shorted.

Re:*yawn* these have around for years?

[JesseMcDonald]

Is there some term that is used to distinguish connectors with / without this functionality, so I can buy the right kind?

I gave up on finding USB Charging Specification-compatible chargers a while ago and just picked up a "charge-only" USB cable, which does the same thing as the adapter in this article: short the D+ and D- pins on the device side. This lets any standards-compliant (i.e. non-Apple) device know that it's safe to charge at full speed, so it should fix the problem so long as your charger can handle the current.

You can tell whether an Android device is charging properly by looking at the Battery pages in Settings. It should say "Charging (AC)" to indicate a full-speed charge, or "Charging (USB)" to indicate that it's limiting itself to 100mA.