http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/ Engadget Comments for How-To: Add USB power to your alarm clock http://www.engadget.com/media/feedlogo.gif http://www.engadget.com en-us Copyright 2012 Weblogs, Inc. The contents of this feed are available for non-commercial use only. Blogsmith http://www.blogsmith.com/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.clockandbarometerstore.com/RetailProducts.aspx?catid=114
Finest Quality Alarm Clocks in traditional and contemporary designs - Avail 30% discount – Alarm Clocks – Branded Collection - Switzerland, Swiza – Great Savings – Call us on 0800 840 4001.
]]>Aug 7th 2008 10:23AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/( The only way to charge my mp4 is by USB ) ]]>Nov 6th 2008 1:36PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
I'm gonna put a USB clock on my.... hey wait a minute.]]>Jun 13th 2006 3:17PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 3:19PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
Unfortunately, you lost me at "LM7805 power regulator." This may be a little out of my scope...]]>Jun 13th 2006 4:10PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 4:12PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 4:17PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 4:24PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 4:47PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
these mods are so awesome!

too bad i fried my xbox mainboard trying to mod it :]]>Jun 13th 2006 4:49PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 4:50PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/It's a type 'A' pcb mount recepticle.

]]>Jun 13th 2006 4:55PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 5:52PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 6:28PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 6:52PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 7:28PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
Check out either the SiK din, or the SendStation PocketDock Line Out USB. The PocketDock comes with audio cables, but the din doesn't. Or you could just get one of Apple's docks. Heh.]]>Jun 13th 2006 7:55PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 13th 2006 8:09PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/]]>Jun 13th 2006 8:57PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.instructables.com/ex/i/1686FF3E41011029AC23001143E7E506/]]>Jun 13th 2006 11:46PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/The electrics of your car is not the same as your beloved alarm clock! In short, the voltage on your car varies greatly, and more components are needed to ensure that you don't fry the LM7805 , or even worst your ipod!!

Great article!]]>Jun 14th 2006 2:23AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 14th 2006 6:19AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 14th 2006 9:36AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
[or just buy a flashlight :)]]]>Jun 14th 2006 9:50AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jun 14th 2006 11:31AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
The problems is that you really do need decoupling capacitors to protect your electronics and to avoid shorting the DC inside your clock, and you also need a heatsink even at 500mA.

Furthermore, some of these cheap USB-only-for-power things will happily draw as much current as they want from the port. Computer USB chipsets have current limiting circuitry on them to never allow mor than 500mA out but obviously the LM7805 has none.

If you want to trust your cheapo USB phone charger not to short or set fire to the LM7085 inside your radio, fine by me, but a couple of caps and a heatsink isn't a significant expense for this.

An "upgrade" would be to move to a switchmode regulator which helps the heat problem significantly and also draws a little less power too (not that it's a big concern).]]>Jun 14th 2006 1:58PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
The post states that you should consider adding a capacitor to smooth out the voltage and points out that you should add a heat sink for higher draw applications. For serious apps, adding a seperate power supply and tapping the AC (before or after the transformer) is the way to go.

We're driving a LED with the thing - Very low current draw (like 25 to 50ma) No prolem for a 1.5amp rated lm7805 without a heat sink.

Your comment should help clarify issues for people with questions.]]>Jun 14th 2006 3:29PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/the input is connected to the clock?thn the clock works as a battery?
and the output to the usb?what for?
]]>Jan 25th 2009 4:21PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jul 9th 2006 7:22AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
Another thing to remember is that you are taking power from the clock supply 500mA would probable cook your clock as well as anything connected to it. You would be better off buying a cheep powered usb hub and then pluging in anything usb into this.

Ben]]>Jul 20th 2006 10:18AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jul 27th 2006 10:57PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.circatek.co.uk]]>Apr 8th 2009 6:09AMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/
In fact, USB devices must only draw a maximum of 100mA UNLESS and UNTIL they negotiate with the host controller to draw up to 500mA as a "high-current" device type. Therefore, it's a pretty good bet that any device you plug into it will draw 100mA or less (because it has nothing to negotiate with for more).

Heat sinks are always a good idea. Just dropping 9V to 5V at 100mA will generate ~0.5W of heat. This can build up the temperature inside a closed container and derate the current-handling ability of your 1.5A regulator! I get a finned heat sink, drill a mounting hole and three wire holes, and mount the entire heat sink + regulator on the outside (usually in back) so that the heat stays outside.]]>Sep 13th 2006 6:56PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://onlineclock.net

The USB is already built-in ! For lazy slobs like me. Still, if I had the time...]]>Oct 8th 2007 3:52PMhttp://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/http://www.engadget.com/2006/06/13/how-to-add-usb-power-to-your-alarm-clock/Jan 18th 2008 6:45AM