The humble USB cable is part of an electrical revolution • Hacker News Board

Re: The humble USB cable is part of an electrical revolution

#41

Post by icelancer » Sun, Dec 01, 2013, 9:12 AM UTC

xlayn wrote: post #23

kabdib wrote: post #3

It's going to be interesting, from a security standpoint. One of the original cracks on the PS3 was via the USB stack. I'd not go plugging my computers or phones into jacks that I don't necessarily control. I can see a market for buffering devices that allow power through, and perhaps do power negotiation for you, but that do not allow data traffic. I believe these devices already exist. though I don't know how sophi…

or you can just cut the two data cables or put a piece of tape on the two data connectors on a usb2 cable.... pleaaaase and it's almost free...

Doesn't solve the low/high power signal for rapid charging.

Re: The humble USB cable is part of an electrical revolution

#42

Post by asdfs » Sun, Dec 01, 2013, 9:26 AM UTC

fab13n wrote: post #29

100W at 5V means 20A. We usually recommend 4 A/m2 max for copper conductor sections, so it would require two 5mm2 wires in the cable here. It would feel more like a rod than a cable IMO. Anyone got an idea how they plan to address this? Higher voltages?

100W is done via 5A @ 20V.

https://en.wikipedia.org/wiki/USB#USB_Power_Delivery_specifi...

Re: The humble USB cable is part of an electrical revolution

#43

Post by skreech » Sun, Dec 01, 2013, 9:28 AM UTC

Disregarding the flamboyant visions of an electrical revolution, just having a flippable physical interface (and hopefully not in three different sizes, two of which always gets mixed up) would be a huge enough leap forward for everyday life.

Re: The humble USB cable is part of an electrical revolution

#44

Post by TazeTSchnitzel » Sun, Dec 01, 2013, 10:07 AM UTC

jcampbell1 wrote: post #20

kochb wrote: post #15

This was posted a month ago as well, discussion: https://news.ycombinator.com/item?id=6591186

I find it notable that this article entirely ignores the EU's Common Electrical Power Supply law ( http://en.wikipedia.org/wiki/Common_External_Power_Supply ), which effectively mandated that all smart phones sold in the EU use micro USB for power. This had a swift and noticeable effect in the diversity of connectors in phones (basically Apple is the only maker that doesn't use micro USB and this change happened at t…

China also started requiring all phones licensed there to use USE charging.

Re: The humble USB cable is part of an electrical revolution

#45

Post by mjn » Sun, Dec 01, 2013, 10:19 AM UTC

sigvef wrote: post #16

kabdib wrote: post #3

It's going to be interesting, from a security standpoint. One of the original cracks on the PS3 was via the USB stack. I'd not go plugging my computers or phones into jacks that I don't necessarily control. I can see a market for buffering devices that allow power through, and perhaps do power negotiation for you, but that do not allow data traffic. I believe these devices already exist. though I don't know how sophi…

There are USB condoms http://www.usbcondoms.com/

HN discussion: https://news.ycombinator.com/item?id=6379272

Re: The humble USB cable is part of an electrical revolution

#46

Post by jakobe » Sun, Dec 01, 2013, 10:22 AM UTC

nwh wrote: post #22

jakobe wrote: post #21

Earlier quoted context omitted.

Even worse than USB is Firewire, which, if I am not mistaken, gives direct memory access to whatever device is connected. However, manufacturers are already realising that blindly trusting every USB host is a bad idea. For example, iPhones now ask if you want to trust if you connect to a previously unknown computer via USB. If you chose not to, your iPhone will take power, but won't allow data access. Therefore it's…

> Even worse than USB is Firewire, which, if I am not mistaken, gives direct memory access to whatever device is connected. Both FireWire and Thunderbolt offer DMA. There's publicly available tools that allow you to extract passwords, remove lock screens and find keys in the memory of running devices using either type of port.

Here's a good article on vulnerabilities in Thunderbolt: http://www.breaknenter.org/2012/02/adventures-with-daisy-in-...

Turns out OS X 10.7 and later at least disable DMA access while the computer is locked (unless fast user switching is turned on).

Re: The humble USB cable is part of an electrical revolution

#47

Post by jdietrich » Sun, Dec 01, 2013, 10:22 AM UTC

x0x0 wrote: post #5

kabdib wrote: post #3

It's going to be interesting, from a security standpoint. One of the original cracks on the PS3 was via the USB stack. I'd not go plugging my computers or phones into jacks that I don't necessarily control. I can see a market for buffering devices that allow power through, and perhaps do power negotiation for you, but that do not allow data traffic. I believe these devices already exist. though I don't know how sophi…

(I'm not an engineer). I a similar article; iirc android phones could be owned by plugging them into a hostile usb connection. I wonder, though, if you couldn't produce a simple adapter that just drops some of the pins? Maybe I don't know enough about usb.

You can buy just such an adapter from the link below; Version 2 is in the works, which will include a microprocessor to allow for full-power charging.

http://int3.cc/products/usbcondoms

Re: The humble USB cable is part of an electrical revolution

#48

Post by furyg3 » Sun, Dec 01, 2013, 10:35 AM UTC

Brakenshire wrote: post #10

This is interesting as a contribution to the solar net metering debate. If you have a local low-voltage DC network, perhaps backed up by a UPS, you can charge the UPS battery using solar, and that means that solar electricity generated on-site automatically displaces grid electricity at the retail rate. That means that solar would only need to compete with the retail price of conventional electricity, and not the gen…

Of course you also have generation costs, though (The solar panels, the UPS).

Re: The humble USB cable is part of an electrical revolution

#49

Post by michaelt » Sun, Dec 01, 2013, 11:15 AM UTC

GammaDelta wrote: post #18

ams6110 wrote: post #6

One problem with low-voltage DC is that according to Watt, to achieve equivalent power (watts) at a low voltage, current is higher. And heat is proportionate to current squared. So you can't send a lot of power at low voltage because you lose a lot to heat. That means low-voltage runs have to be kept fairly short, or very low power, limiting their usefulness.

Funnily enough USB's inability to work over longer cable lengths works in its favour here. Generally we don't rely on anything working over 3 metres. Wikipedia says "the maximum power supported is up to 60 W at 20 V, 36 W at 12 V and 10 W at 5 V" [1]. For a typical 3 metre 20 gauge USB cable 10 W power delivery will cause a voltage drop from 5 to 4.6 V. This is within the +0.25/-0.55 specified for USB 3 [2]. Since no…

Yeah, it's fine for USB cables. The difficult bit would be if you're planning on cabling an entire office building from one low voltage DC source, like the solar panels the article mentions.

If you want 60 watts at 20 v is 3A, and if you want to supply a hundred ports with that you're going to need copper cables the size of your finger.

Re: The humble USB cable is part of an electrical revolution

#50

Post by perlpimp » Sun, Dec 01, 2013, 12:02 PM UTC

On wikipedia I can count at least 6 different types of connectors for different voltages/current, sounds like a deal breaker to me.

I'd rather have devices adapt Power over ethernet which requires just one cable and gives many more opportunities for networked future of devices.

in fact http://www.commercialintegrator.com/guide/product/details/po... http://www.creativeplanetnetwork.com/the_wire/2012/06/14/fsr...

So I think R45 is a better standard to rely on, that it does have option to carry networked data and intelligently carry voltage to charge usb powered devices.

you can already get RJ45 hubs on the cheap too, ones with 8 ports and such.