Instead of the 250ma limitation, I'd like to have a USB hub that can pump out a couple of watts, so I can create USB devices which are fully-powered (i.e. a table lamp) but fully controlled via the USB interface.-- jojo99, Sep 25 2003 (?) FireFly USB Lamp http://www.officewi...rod/FireFlyLamp.htm"USB powered desk lamp" [bristolz, Oct 04 2004, last modified Oct 06 2004] USB 2.0 PCMCIA card http://www.team-sol...PCMCIA/TSCUSB22.htm"This USB 2.0 CardBus Controller has the ability to sustain a high-power (500mA)" [half, Oct 04 2004, last modified Oct 06 2004] (?) Firewire topology http://www.genitech...firewire_vs_usb.htm [kbecker, Oct 04 2004, last modified Oct 06 2004] Firewire connector http://www.ramelect...irewire-pinout.html [kbecker, Oct 04 2004, last modified Oct 06 2004] IBM: Powered USB http://www.poweredusb.org/From omr's now defunct embedded URL. [jutta, Jun 24 2006] I already have to run my computer without the casing to keep the heat down and Imagine how long my laptop battery would last with a 60-100 watt bulb sucking from it. P.S. Those aren't my bones. I actualy have no objection to this idea as long as my usb printer, mouse and microwave still work.-- Dagwood, Sep 25 2003 My Canon flatbed scanner is fully powered by the USB connection.-- bristolz, Sep 25 2003 What you need is a powerstrip with a USB connection. I have often thought that a deal like this would be very neat. You could use it to make your own custom christmas light display, among other things.-- bungston, Sep 25 2003 /Bungston/ You would have to buy specialized lights to hook into the powerstrips usb port when you can already buy regular lights for three bucks a strand. Plus, how do you get your computer to interface with a powerstrip.-- Dagwood, Sep 25 2003 Rephrased: How do you get your computer to tell the lights to blink on an off to the beat of the Bob and Doug McKenzie's, 12 Days of Christmas MP3 your playing?-- Dagwood, Sep 25 2003 Looks like it sits on a desk to me, [Mr Burns]. Isn't that the sole attribute that defines a lamp as being a desk lamp?-- bristolz, Sep 25 2003 Which begs the question: How large is your desk? I work in a cube, and it doesn't take much. I'm considering switching to candles, but will have to check the fire codes.-- Worldgineer, Sep 25 2003 //I'd like to have a USB hub that can pump out a couple of watts//
A 250mA USB port can indeed put out "a couple of watts". To be precise, 2.5 watts.-- supercat, Sep 25 2003 Eh?-- phoenix, Sep 25 2003 [Dagtoad!] No specialized lights would be needed. Regular $3 lights would be plugged in. The robot in the USB powerstrip would control power to the individual plugs. Using this strip you could make synchronized displays usings 3 strips of ordinary xmas lights, your bargain bin lightup santa, your stolen Miller Lite neon sign, and your plug in marital aid device.-- bungston, Sep 25 2003 Oh! I should have guessed, The robot.-- Dagwood, Sep 25 2003 I don't think my thought was clear enough. It would be great to have a USB port replicator which could source 100w in power overriding the 750ma or so limitation from basic USB. I could then, without multiple power adaptors run all sorts of interesting equipment via usb with USB providing power, input, output, and control (via Computer). It's a problem for doing anything more than a toothbrush with USB power.-- jojo99, Sep 25 2003 500mA (2.5 W) available from a USB 2.0 device. (link)
100W @ 5v => 20A => Big USB cable.-- half, Sep 25 2003 Also big problems if you happen to feed those 20 Amps to a legacy device that isn't prepared for it.-- krelnik, Sep 25 2003 [jojo] I completely agree, but the people who designed USB probably live in another reality where there are always enough power outlets available. Perhaps it was designed by aliens to slow down technological development on earth.
If you want more power for the real world try fire wire. It specifies 40V@1.5A at full power. It also allows daisy chains so you don't have wiry spiders lurking in dark corners of your desk, and the shape of the connectors lets you recognize which way they go in while USB just offers a small square with only 10% hit rate (Murphy's law) on the first try.
USB should have died the day it was born.-- kbecker, Sep 25 2003 Mr. Burns: Yeah, you're right. Someday I'll learn to do math [btw, did you know Google does math, complete with dimensional analysis?]-- supercat, Sep 26 2003 kbecker: One advantage of a medium-power standard like USB (250mA is a lot more than e.g. a normal serial port can provide) is that while it provides enough current for many devices, the current level is low enough to be macroscopically "safe". The more current is available, the greater the likelihood of a malfunctioning device causing serious damage or even a fire. Admittedly one could go a fair bit beyond 250mA@5V, but 60W starts to have some risk.
Also, if only 250mA is available, people will limit devices to 250mA. If 1A were available, many devices would use more than 250mA, thus limitting the usefulness of devices with laptops.-- supercat, Sep 26 2003 Couple more clarifications. 1) I want a high-power HUB, not a high power USB on a computer itself - but then, why not? Honestly, 128 USB plug-ins and 250ma restriction? Less than 2ma per plug for power if you want? 2) I'm not sure what's 'more dangerous' - a 6-element power strip with 120 or 220v with 6 power supplies, or USB 5v and a few watts running along. I'll take the USB low-voltage. 3) USB is not engineered for power distribution, but then TCP/IP wasn't designed for VOIP, but it works. USB's just a layer.
Good questions.-- jojo99, Sep 26 2003 Mr. Burns: Your math was right and mine wrong. I should have gone to Google and typed "5 volts times 250 milliamps". It would have told me 1.25 watts [really neat feature--ever try it?]
The design philosophy behind USB power is that it provides enough juice for most USB devices, without putting a totally unreasonable demand on laptops. Although some devices like scanners may be borderline, most devices will either less power than USB can provides or else will require more than USB could practically provide.-- supercat, Sep 27 2003 i've got a few things that run on the existing USB power output, only problem is if i hub 1 into 2 theres not enough energy to run them.-- HalfwayHebrew, Sep 27 2003 http://www.poweredusb.org/whatispusb/whatis.html-- omr, Dec 18 2003 random, halfbakery