Dart: The World's Smallest Laptop Adapter
kickstarter.com
kickstarter.com
[1] http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-ap...
[2] http://www.righto.com/2012/05/apple-iphone-charger-teardown-...
But besides efficiency, i'd also like to see RF interference measurements on this one. There is a reason good power converters are fixed in one voltage output and use transformers...
Also you notice they use a lighter wire than most laptop power supplies would and no ferro loop at the end to reduce the noise to the device.
Maybe I missed it, but I don't think I saw a UL approval on the device. I also don't think there is enough room in the case to have a thermal cut out, and a fuse/breaker. Which you really need on a power supply.
I'd love to be wrong on all this. I hate carrying a brick (though mine is about the size of half a deck of cards).
The real thing for size is the transformer and other magnetics, which decrease with frequency, hence why this uses VHF frequencies. Output filters can also be made smaller at higher frequencies, and Ken Shirriff's iPhone charger teardown above shows a small ferrite ring _inside_ the charger case for high frequencies.
UL Approval is probably under on the "Production Timeline" (2/3rds down) under "Submit for initial regulatory certification (4 months)", which is set to begin now (Apr-May).
As for the wire thickness, it doesn't seem that much thinner than my Macbook Charger, which is also 65W. The production timeline on the kickstarter leaves them time to change to a thicker one.
The big question of course, is the feasibility of the VHF AC-DC conversion. FINsix have a paper (http://finsix.com/assets/files/FINsix_Tech.pdf) but its not very long or detailed, and I don't know enough to criticise it if it was.
Will this work on your next laptop? Probably. Can the Dart team guarantee that the device will "work with all major PC brands" manufactured in the next year? Probably not. Is that risk worth the extra money you save on a pre-order? That is up to you to decide.
Also, laptops have very flexible power input circuits that will accept a wide range of DC input: they'll start running from ~12V (the voltage of an almost-dead battery), and go as high as the voltage specs on the input components allows - 25V (filter caps) is the usual absolute upper limit. Higher voltage means lower I^2R losses but manufacturers like to leave some safety margin, which is why 20V is somewhat of a de-facto standard given the parts available. The general power distribution circuits in a laptop are like this: there's a main power rail, whose voltage varies with battery voltage when running on battery, and is the DC-IN voltage with the adapter plugged in. The voltages for the CPU, GPU, chipset, etc. are all generated by DC-DC converters supplied from this main rail. There's a set of diodes/MOSFETs that wire-OR together the battery and DC-IN to the main rail, preventing current flow in the wrong direction. It also powers the battery charger.
I've read a lot of laptop schematics, and all of them use very similar power circuitry, often with the same components. The only real concern with device compatibility is in the ID schemes that some manufacturers use, either to "lock out" third party adapters or encode wattage selection. The simplest ones are nothing more than a resistor in the plug, different values for different wattages (IBM/Lenovo is one example). More complex ones use a 1-wire interface to an EEPROM or other storage element (Dell, Apple) (http://www.laptop-junction.com/toast/content/dell-ac-power-a... http://www.righto.com/2013/06/teardown-and-exploration-of-ma... ). Then there's all the others that have no ID at all, just +/- input, and these are the most compatible.
About the Dart itself: the technology used here (VHF SMPS) has been around for a long time in military/aerospace applications, where size/weight is more important than reducing switching losses.
http://www.eevblog.com/forum/crowd-funded-projects/vhf-lapto...
I would be shocked to see even one laptop ship with USB power before 2015.
E.g. the EEE 1000HE uses a 12V adapter, and it has 16V caps in its power circuit. Probably the same for the Surface/Pixel.
Yes, there is: it causes massive electronic waste because of incompatible chargers. Expect the new EU regulation that covers phones etc. (that replaced "voluntary" measures) to be expanded to cover laptops too, or at least for manufacturers to get threatened with changes to th regulation, if manufacturers don't voluntarily switch to USB once suitable chargers start being widely available.
However, the solution is not a grossly overcomplicated standard like USB. It is a 20V barrel plug. Maybe if you want to get really fancy, include a resistor on a third pin for wattage encoding. Standardise on that instead - or pick an existing size - there are enough to choose from already ( http://en.wikipedia.org/wiki/Coaxial_power_connector#Standar... ).
With the exception of the phone charging example, I would agree. The PS/2 protocol is vastly less complex than USB, and parallel ports are so simple they can be used as GPIOs with ultra-low guaranteed latency. Phones migrated to USB because they already needed the bulk data transfer capability along with power, and USB made for a good fit.
You won't be able to charge your phone with your standard barrel plug laptop charger, so you'll still have to carry two adapters when you travel.
The Dart has both USB and a barrel plug, which is the same as many other aftermarket adapters. (They could've made this more obvious in the marketing material, e.g. by showing USB devices plugged into it and not just laptops most of the time.)
I'll choose a laptop with a big robust barrel plug, and one that can be powered from anything outputting 12-24VDC, over one with a USB socket and requiring complex negotiation protocols to even start consuming power. It's the KISS principle. Standards that try to do everything don't tend to do any one thing particularly well, and introduce unnecessary complexity.
Detection of power delivery plugs is mechanical for standard A connectors (their male standard-A connectors are 1.3 mm longer so they could be inserted deeper in female power delivery connectors than conventional connectors so metallic shield connects detection pins) and based on detecting resistors and capacitors between ID pin and ground and power pins for other connectors.
For voltage negotiation new simplified bus and protocol was invented; it uses high frequency transmission on the same pin as power.
So even if adding a new USB port for charging is cheap and easy, the manufacturers might still have reasons not to do it.
Also, is anyone really innovating in Laptops these days? Is there a reasonable expectation that something like "A new type of charger" can even happen in the next 12-24 months?
Nobody is buying it just for the usb port; it's bigger and more expensive than existing usb outlets.
Additionally, If you have a MacBook Air it doesn't seem significantly enough smaller than the 45W MBA power brick - not to justify the higher price, anyway.
UPDATE: meant 45W, not 65W, corrected
Apparently the thing with this (as magnetic power connectors have existed for a long time) is that there are, at the very least, claims in Apple's patents that differ from previous examples and patents[1].
So basically the novel thing isn't magnetic power adapters.
[1] http://patents.stackexchange.com/questions/200/prior-art-for...
The other point you might "attack" the claims on (ie in designing around them) appears to be the inclusion of "bias". Mind you it's not entirely clear¹ what is meant (without referring to the description) by "biased" here: claim 6 suggests it means sprung in some way.
Edit: looking at a couple of pieces of the prior art http://www.google.com/patents/us7311526#backward-citations it seems the main innovation in the Apple claims is probably the symmetry / reversible nature of the connector. There were already circular connectors, eg the cited US3808577, so Apple's claims may have had to work around those - hence the construction including the symmetry clauses. Seems a magnetic connector is well doable even without any need for invention, just based on expired patent disclosures.
http://patft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=...
> An electrical plug and receptacle relying on magnetic force to maintain contact are disclosed. The plug and receptacle can be used as part of a power adapter for connecting an electronic device, such as a laptop computer, to a power supply. The plug includes electrical contacts, which are preferably biased toward corresponding contacts on the receptacle. The plug and receptacle each have a magnetic element. The magnetic element on one or both of the plug and receptacle can be a magnet, which is preferably a permanent rare earth magnet although electromagnets may also be used. The magnetic element on the plug or receptacle that does not include a magnet is composed of ferromagnetic material. When the plug and receptacle are brought into proximity, the magnetic attraction between the magnet and its complement, whether another magnet or a ferromagnetic material, maintains the contacts in an electrically conductive relationship.
What part of that abstract doesn't also describe the magnetic connector on a Japanese electric water kettle?
http://finsix.com/power-platform/#section-frequency-innovati...
And yet, there's a high chance that you are 100% right.
I find it sad that we'll have to always consider that particular scenario from now on. Stupid Facebook.
I don't think it really does. Kickstarter is expressly a way of getting resources people interested in offerings to launch them when the funds to start the to launch the offering wouldn't otherwise be available, in order to create sustainable businesses that would otherwise not get started because of lack of access to funds to start them.
Obviously, one of the very common things to do with a viable business once it is running -- and one that maximizes the return for people who are best at (or most interested in) launching things -- is to establish the business, sell it to someone interested in running it for the long term, and use the proceeds to start more things.
While particular exits might bother some people, I don't see how its contrary to the core ideas on which Kickstarter was created, or a sad thing. People who are well suited to getting the ball started on something aren't always best suited for later stages.
People have had to consider that scenario for pretty much any business. Especially fledgling companies, as they might get bought by someone else or they might simply go bust. There's nothing specific to Kickstarter about this.
The implications of the technology are a lot bigger than laptop supplies and I am sure they know that. Laptop supplies seem like a good way to raise some cash without dilution while they work on harder problems.
http://www.amazon.com/Universal-Portable-Charger-Charging-La...
But I doubt they'll make do without the ferrite core.
The smaller the device is, it usually means more interference being generated, and the higher frequencies make it more complicated.
At the headline, I had the kneejerk doubt that they could fit laptop-level power in such a small adapter, but they claim that's exactly why their product is interesting.
Nevertheless, I'm going to wait for the first wave to prove itself and for them to iron the kinks out (there are always kinks in a first-gen HW product). As such, I hope this is a true "kickstarter" that starts company momentum and isn't, like too many others, a one-shot deal.
I use the HN facebook feed (yes I do) and there is no direct link on it, just the video (maybe specific to KS?). Also the music in the video is distracting. It is way overcompressed.
But man, what I wouldn't give for an adapter that make it easy to pack by having some clever and clean way to wrap the cord. It doesn't look like this one does.
Coverage I helped write: http://www.thinkcomputers.org/finsix-shrinks-laptop-power-br...
I would hope Apple was working on a smaller power brick, its kind of silly when my power adapter is almost as heavy as my Macbook Air 13". yeah, i know #firstworldproblems
The Dart might look like a small device but its an incredible feat -- specially since it needs to safely work with all laptops and devices. Very excited about the future of the product.
http://www.theinquirer.net/inquirer/news/2319855/eu-pushes-f...
main reason for chargers to be bulky is costs (nobody "cares" when they buy the laptop, they only realize later..), not technology.
other than that it's dearly needed for many.
I is perfectly fine for me.
I assume that there is a good reason for this.
Apple sure doesn't like to make it easy for third parties to be physically compatible with them.
(Emphasis added)
It seems this is in fact fit for most of the world.
I usually leave it at home. The adapter isn't large, but you have to take it off for transport which makes it awkward to use.
(Yeah, Apple doesn’t do prices below €20, but it’s a pretty nice and compact charger. It’s longer than the US charger, but very flat, which I think is a better form factor in many situations.)
All of this is to say that these adaptors are super annoying, look ugly, add bulk and are easy to forget, so never an ideal solution.
[1] http://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Type...
http://ep.yimg.com/ca/I/theshorelinemarket_2310_643977735
Inelegant? Sure. Large? No.
In the UK, the plug adapter is going to be twice as big as Dart:
It's also only 50% of the size of my current adapter, not a quarter, although to be fair, that one is only 33W. Does have a UK plug though! Dart plus plug adapter is probably no smaller.
Pledge $130 or more
Global Dart: You live abroad and you want a Dart. This reward is for you. The Dart will work internationally, but you'll need a plug to match your outlet. This reward includes the Dart PLUS a plug adapter for your region. Your Dart, your color holds for this offer. Choose your favorite from among our signature Kickstarter colors. Please note the later estimated delivery date. Not MacBook compatible. Shipping is included.
Estimated delivery: Mar 2015
Moreover, the North American ungrounded plug is one of the easiest plugs in the world to pull out of a socket. So if I plug Dart into a adapter for any other part of the world, plug the adapter into a socket, and then try to pull it back out, Dart will separate from the adapter and leave the adapter in the socket. It happens all the time when American electronics are used abroad, and it's extremely annoying.
I've barely had success with plugs that weren't this heavy.
How much battery life do you get? Half an hour?
Under windows they told it will get better battery life mostly because of better drivers support. But I never tested it.
This is Dell Precision M6600. This one and most other Precisions will consume similar amount of power from PSU. Not sure why all the downvotes. Even MacBook Pro I have requires 85W