USB wall outlet - new standard for DC plugs? | Hacker News Reader

USB wall outlet - new standard for DC plugs?

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122 pointsjonnytran67 comments

Anyone know more details about this, and if it's been approved? My understanding is that everything that's part of a home wiring system (like this) needs to go through a bunch of test (UL, etc.) before it can legally be installed in a house - and that seems like a lot of work for a small-ish third-party accessory company to go though.

EDIT: Looks like it's not yet - from the ordering page, "This item is currently waiting on final UL Approval. It is scheduled to begin shipping in early 2010."

Was just about to post that its awaiting approval... hopefully this idea will catch on!

"Patent pending" might stop that from happening...

Why?

He is saying that if there is a patent, not as many people will try to implement this.

Like CD? BluRay? DVD? Patents don't stop things from being implemented. Sounds like propaganda to me.

That depends primarily on whether the patent holder licenses it, and for a reasonable price.

AFAIK they can patent it all they want, if it's introduced as an acceptable electrical standard (with the mass usage of USB devices, this possibly isn't too far off) then the patent means shit and there's little to no recourse the company can take.

"before it can be legally installed"

Does that only count for wiring that is attached to a public grid?

E.g. if I have a homebrew energy system that doesn't touch a grid, am I free to attach anything I want including such USB outlets?

Depends; it would be reasonable for a dense city to still have restrictions since fire has a propensity to spread and if your place burns down, your neighbors' might too.

The UL is a certification program, They can't really tell you what you can/can't install in your own home. They can't even tell you what you can/can't sell to someone else. The issue is that most distributors won't buy/sell things w/o UL approval (for good reason). I'd most certainly guess that the creators have had them in their home for some time.

When I worked in commercial electronics, it was very typical for engineers to install development products in their home, long before UL approval.

E.g. if I have a homebrew energy system that doesn't touch a grid, am I free to attach anything I want including such USB outlets?

It needs to meet the building codes if you ever plan to sell your house or collect from your insurance policy if it burns down.

Now we need a USB surge protector.

...and a company like Monster to charge 10x what it costs to make the damn protector because it's "better quality".

But the connectors are plated in GOLD!

Give me a 10ft gold cable, then I'll believe it has anything more than a negligible effect on impedance.

and gold connectors on both ends and gold pcbs and solder...

My understanding (from memory of an electronics class a few years ago) is that gold is used for the connectors because it resists oxidation better. Copper is actually a better conductor of electricity.

For sure. corrosion just isn't a big problem for most consumer or home electronics though. Where it is, it's a problem in more than just the connectors, because most electronics aren't sealed. (it's especailly useless if the connectors on the $100 board aren't protected... and the $3 cable is..)

Only problem with this is that now mains wiring is going to be part of the obsolescence cycle.

I remember seeing USB ports on cheap computers in '98 and you can still get normal to mini adapters like http://electronics.become.com/6ft-usbamini-b-device-usba-to-... that fit in those slots.

I don't believe the power spec has changed in that time.

I thought they were bumping the power spec for usb 3.0?

Does anyone know if there are any plans or way to add universal DC to the standard electrical system? It seems with all the electronic devices it is wasteful to generate AC and then convert to DC in switching power supplies and in wall-warts, etc. This plug device looks like it just puts the transform in the wall so does nothing to solve the conversion losses. Would it be practical to add a DC offset, say +5v to the AC sine wave to directly drive electronics in the home? I'm not an EE so maybe the idea is crazy but I hope someone can explain.

A DC offset would have the negative side effect of causing AC wall transformers to saturate, redering them useless. Also, as far as I know it would cause problems for many kinds of AC motors. True, you could bypass the DC offset with a series capacitor, but then you would suffer efficiency losses in larger appliances, in addition to added cost and complexity. The problem with having +5V centrally regulated and then distributed throughout the house is wiring resistance losses. Let's say you decide to use 16AWG wire, and have a run of 100' to a hypothetical outlet (not uncommon in even a mid sized house). that means your round trip length is 200'. Given the resistivity of copper, the resistance of such a wire is 1.26Ω, and with .5A of current your voltage drop would be .63V. Therefore, 5V would leave the distribution box, and only 4.37V would be available at the outlet. Worse, Pin=5V.5A=2.5W, Pout=4.37V.5A=2.19W. Efficiency of just the transmission system is 87%. You can get a good power factor corrected switching converter that can do better than this just plugging into the standard wall outlet.

Thanks

Or to put it another way: There is a reason that our power stations transmit AC, not DC. It is the electromagnetic equivalent of twisted pair versus straight copper: AC signals propagate over long distances. DC signals have a high loss.

Look up the Edison-Tesla rivalry for an interesting historical debate on the subject (Edison was a real jackass).

Cool, but too bad that 5V is on the low side to run all electronics. It's easier to downgrade 12V->5V than to step up, so I'd prefer if we make new building wiring it be 12V.

While there's some truth to that, I'm not aware of a de-facto standard 12V connector.

I guess SATA power could be interesting as it has 12V, 5V and 3.3V rails, but I don't think it's designed to withstand as many plug cycles as USB.

Firewire can supply power at 12V, but that's not standardised, so no device can rely on it.

Many devices use 12V, but they use a vast spectrum of different plugs and sockets - many are coaxial power connectors of different shapes and sizes, some are not. USB is a surprisingly good choice, as it's standardised at 5V with a minimum of 100mA and the option to draw up to 500mA. It's also vastly more popular than any other similar connector.

I'd say the closest thing we have a 12v standard is the barrel plug used in a car cigarette lighter port. Of course, that's a pretty ugly solution for an outlet.

"Pretty ugly" is an understatement. I don't think I've seen a single plug design that is less reliable.

My favorite airport would be the first to start using these.

In that case your favorite airport is called Boston Logan, Terminal E (I haven't checked the other terminals). Most passenger-oriented power plugs have USB, too, albeit it's a different design from what's in the link. WiFi is free, sponsored by Google.

SJC has USB outlets in the terminal. Not quite as slick as this one, but eh.

I can verify that. Did you see these & wonder if they had data connections ready to snare the unwary?

Reno Airport has these - though, I found using the Apple AC->USB dongle worked a bit better at charging my iPhone for some reason - seemed to level up more quickly.

That's likely because USB (as strictly defined by the spec) can only put out a limited amount of power. Some devices are made to be able to handle more than is strictly necessary to meet USB specs. So given a comparatively powerful AC outlet as opposed to a USB power source your iPhone can charge more quickly.

Most airports have had USB charging ports for a while. At least all of the recent remodels that Southwest has done seem to include them.

> the USB ports only draw power when something is physically connected to the port.

Am I mistaken that this is a physically impossible claim?

How do you figure?

The wall-plate most probably has a AC-DC converter in it, and you're correct in thinking that these draw a small amount of power even under no load. However it would be almost trivial to completely turn this off when there is nothing physically plugged into the port using an electromechanical switch, and it makes sense to do this to avoid wasting power when the port is unused, so I suspect this is exactly what they have done.

Technically speaking yes it will draw power, all wiring draws power (the wires develop capacitance, but there's also electrostatic leakages around the bare connectors, but at 110/240V it's negligible, this is a concern around 10,000V+, with DC it likely has no electrostatic leakage, and very little drain due to capacitance.

However, what I believe you're thinking about is the transformer required to turn 110V->5V and yes you're correct. An old school transformer would drain a few watts when inactive, however the current types of transformers used in Wall->USB devices provide virtually no drain, perhaps less than a watt, so will have no noticeable effect on your electricity bill.

Simply put, changing say 20 wall sockets in your house to one of these USB devices will likely have less effect on your electricity bill than plugging in a 7W night light and leaving it in.

Not necessarily. They could have designed a physical switch into the receptacle, so that the DC to AC conversion only happens when something is plugged in.

Could possibly be a waste of power depending on the design. If you replaced all outlets with something like this that may have another transformer plus the power regulation circuitry your outlets would be burning power 24/7 (not just when you use it).

At least with an adapter you may only have one and unplug it when its not needed.

from the page:

"Please also note that the USB ports only draw power when something is physically connected to the port. We didn't want a vampire port that continually sucks and wastes power when not in use so this was one of the features on the top of our priority list during the design phase."

Someone could probably make something like this themselves. Of course the "non-vampire" energy saving technique would be slightly harder to implement, but I don't see any other reason why this would be too hard to implement.

Of course without UL approval you might not be covered by fire insurance if your house burned down....

in fact, people already have, but the cost is about 10 bucks anyway!

http://www.instructables.com/id/Outlets-of-the-Future-aka-in...

Something like this seems a little more flexible, assuming it works just as well:

http://www.amazon.com/Belkin-BZ103050vTVL-Surge-Protector-Ch...

Umm...actually, this just replaces the little AC -> USB adapters that many devices come with already. I'd rather have it integrated into the wall so I don't have to worry about losing it.

Of course, I still have to remember the cord. I think wireless data and power is the future.

All that and I still can't get a house built with 3 over 3 wall jacks instead having to deal with 1 over 1 like everybody else.

Anybody who can't find enough wall outlets in their home, raise your hands!

I'd wait until it supports USB 3.0 at least; for now, I'll be content with a simple adapter.

What exactly does USB 3.0 have to do with charging? Will it not be backwards-compatible with 2.0?

Yes, but with 3.0 devices won't the outlet allow more power?

Er, yes: 50% more power is provided for unconfigured or suspended devices (150 mA up from 100 mA), and 80% more power is available for configured devices (900 mA up from 500 mA). Via http://www.everythingusb.com/superspeed-usb.html#4

I suspect that the outlet will give you more power than that anyway - the amperage limits restrict what devices should expect to get, not what hubs may provide them with.

You should be waiting for USB Battery Charging. That is the specification that will define how USB is used as a power source. (Greater amp and removing of different protocol limitations).

what are usb power ports used for? i mean, what devices use them, or is it that devices should use them for some reason?

Mobile phones and digital cameras etc often come with USB cables for charging. The intent is that they be charged from the ports on a computer but there's no reason they can't be charged directly from a socket. The exception is the iPhone, some versions of which will not draw any current from the USB socket until a handshake protocol with the PC is complete, and so they will not charge from this kind of arrangement.

My BlackBerry is the same way; it will only draw current from the USB socket if it detects the requisite software installed on the computer.

my iPhone came with a little transformer that plugs into the wall for charging. obviously there isn't going to be any handshaking there. i was under the impression that all iPhones were like that. are you saying that some aren't?

My iPhone charges from the home adapter that came with the phone, of course. I also have a 3rd party USB charger that I bought two or three years ago for my iPod. It came with both a home adapter and car adapter. The car adapter will charge my iPhone but the home adapter won't.

Your home adapter probably uses the old FireWire power pins, which the iPhone 3G can no longer charge from.

There is also a handshake, but that's separate and (as of the 3GS) only displays a "product not designed for iPhone" warning - even if it displays the warning, it still lets you use the device.

I don't believe it's malicious—the "handshake" is just the device requesting that the USB port switch to high-power mode. The line is always 5V, but the device needs to request to draw anything more than 0.1A.

In the case of wall-transformers for iPods, phones, etc, they're either using an unstandardized handshake (such as the phone shorting its two data lines, which can be recognized by the transformer with just a relay), or they provide power all the time, which could damage a low-power device that was inadvertently plugged in.

But isn't this sipping power ALL DAY.

Or a new way to set a house on fire.

At 5v & 600mA? ...OK.

I think perhaps he means when the "lowest bidder" electrolytic capacitor in the AC/DC converter, with the 2000 hour specified life span (83 days)[1], overheats, bursts, and shorts the AC wiring inside your wall.

Presumably you installed it in a proper outlet box (I like steel) and it will be able to handle the energy released while waiting for the line's circuit breaker to trip without reaching the ignition point of anything inside the wall.

[1] Not that these people would use them, but you find them in a lot of gear. Especially dramatic when their tops are close enough to a case or heatsink to short when they burst.

You might be thinking about how much power DC takes to cover distances? This isn't using only one DC power supply for the whole house though - there's a converter in the outlet.

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