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."

*yawn* these have around for years?

[PhrostyMcByte]

My MP3 player, the nearly 10 years old Cowon D2 [amazon.com], actually came with a power-only USB cable. Maybe their goal was to save money on copper.

Fast charge detection

[_merlin]

This wouldn't allow devices to detect fast charge capability, as that depends on resistances between data pins and power pins, or high-level protocol negotiation if it's an intelligent host with this capability. Devices will only charge slowly (100mA) if at all.

Huh?

[juventasone]

Why does this require a big PCB with three ICs? Why not just simply remove pins 2 & 3?

What does the electronics do?

[irp]

I've apparently made 'USB condoms' myself. A male and female usb connector soldered end-to-end, the data pins shorted together.

This enables my ancient HTC Desire to recognize any usb charger as a dedicated charger, and charge with up to 1 A (in reality significantly less). It is a low tech solution that works.

So why so much electronics on the board??

Re:Fast charge detection

[_merlin]

All PowerPC Macs will current limit if they try to draw more than 100mA without negotiating, not sure what other PCs will or won't do (yeah, I'm out of date on that front). If a device is properly USB compliant it won't draw more than it knows it's allowed to. My Galaxy S3 is pretty quick to go into slow charge mode if it isn't sure it's allowed to go for more. Other reputable devices do the same - don't want to lose your USB logo certification.

Re:Fast charge detection

[inasity_rules]

Make the condom intelligent enough to pretend to be a phone, on one side and a charger on the other with no connection in between. I can't believe I just typed that sentence... Anyhow, I am sure you can get PICs with dual USB which would do that.

Re:Fast charge detection

[jamesh]

They can still try to draw 500mA and let the host cry. I don't know if they will, but wall chargers don't seem to have a complex protocol setup, I don't know how the do it.

I had an aftermarket iPhone charger for my car that was a cigarette lighter adapter with a USB socket on it and then a USB to iPhone cable. One day I was in the office and needed to charge my iPhone and didn't have a charger so I grabbed the USB cable from my car. The moment I plugged it into my laptop, even before plugging the iPhone in, the laptop turned off. No damage. Being naturally curious I tried it again and it was repeatable.

I'd go as far to say that some are basically brain dead

Re:*yawn* these have around for years?

[tjohns]

If you plug your power-only USB cable into a modern charger, you'll find that your phone charges quite a bit slower than you'd expect. Modern chargers use the data pins to negotiate whether a charger supports higher currents.

You don't want a phone to try drawing 2A from a charger that's only designed for 500mA.

Re:What does the electronics do?

[phantomfive]

So why so much electronics on the board??

Wow, you're not kidding. I just clicked on the link, and there is a LOT. With that much stuff, I'd be afraid it'd connect to the phone itself and send the data off to a remote server. It's definitely doing more than just cutting the data lines.

Not the only one out there

[ericfitz]

There's a current KickStarter project called LockedUSB [kickstarter.com] which does something similar, but which also includes a power management chip in order to negotiate higher power charging levels that normally require data connectivity. LockedUSB doesn't appear as big or ugly as the one in TFA. (Full disclosure: I'm a backer)

Re:Huh?

[Darinbob]

I don't have specs handy, but there's power management to consider. A port can be put into a low power or suspend state, where the device is expected to put itself into lower power mode and consume less than the 100ma that's on the power pins. So a two wire cable would not be able to handle this power management and would consume the whole 100ma when charging (not very nice if on a battery powered laptop).

Additionally, I think some devices would need to actually enumerate correctly before they start charging normally. Ie, they won't consume 100ma to charge without being active. Most devices I think keep it as simple as possible so this won't matter for them.

But I think the real reason for the condom is to negotiate basic info so that it can request 500ma for devices that want it.

Re:*yawn* these have around for years?

[timeOday]

Wow, I got something useful out of slashdot today. I have always wondered why my wife's phone won't charge from the cigarette lighter -> USB converter in our car. Is there some term that is used to distinguish connectors with / without this functionality, so I can buy the right kind?