Portable Hubs?

Nahdude asks: "A friend of mine and I tend to have frequent mini-LAN parties in odd places like diners or parks with our laptops. We've been using a crossover cable with no problems, but recently we've attracted some attention from friends, and even some strangers, who want in on the action. So I've looked (without success) for a portable networking solution. Has anyone found and had luck with a battery powered network hub? Keeping in mind that wireless, although neat, will probably be a bit difficult because the expense of mobile wireless cards could be out of range of a lot of the people interested (we had 15 people last week in a bar, woot, but only 2 player games with crossovers because they wouldn't let us plug in a hub)." I haven't seen many of these now, but maybe if someone plants the idea in people's heads we'll see these several years from now...

Comments

Googled

[Anonymous Coward]

http://www.w-linx.com.tw/products/network/mini-hub s.htm

Re:The more I think on it...

[Captain Pedantic]

Nothing personal Cliff, but shouldn't their be a "Google Filter" for postings to Ask /.?

For example, this is the device you're looking for.

How did I find it? Like this. Note the search words; battery powered ethernet hub. Ok, so its a hub, not a switch, but still!

Ask /. is probably the most interesting part of the site (apart from trolltalk of course) but you also get some of the lamest submissions!

Good old Hubby.

[SoftwareTechie]

Try this hub. It is powered from a standard keyboard socket and they can be cascaded together.

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Wireless expensive? Give me a break!

[uradu]

You can pick up a basic 802.11b card for $30, so price is a flimsy excuse. If they can't afford $30, maybe your friends should play battleships on paper instead? Or maybe they can't afford that fancy paper either?

Solutions, wireless, etc etc.

[Andy Dodd]

For one:

Price is a useless excuse for not going wireless. If you search, you can get WLAN cards for $30 on sale these days. And as many pointed out, if you plunked down $1000-2000 for a laptop, you can afford a WLAN card even if it's $100.

That said, for another year or two, strangers are less likely to have WLAN cards. (But this is changing VERY quickly... It's getting to the point that having a laptop without getting a WLAN card is just plain silly.)

So your two solutions are:
PS/2-powered hub. Good if you have a decent mobo, but some laptops don't quite meet the PS/2 power supply spec... And there's no way to tell w/o risking damage to the mobo. Also, it'll drain your battery.

Homebrew battery-powered hub. IMO this is the way to go. There were a few links to a 9V powered one. Note that trying to find the smallest hub might not give you the one with the lowest power consumption. Also, 9V batteries have VERY low capacity compared to AA/AAA batteries. 4 AA rechargeables will cost you about as much (or less than) a 9V rechargeable and last much longer. I think most 9V rechargeables are 15 mAh rated, "cheap" Walmart AAs will be 1200-1300 mAh. Sears has the best deal on NiMhs I've seen - 1500 mAh units, $10 for 4. I have tons of DieHards now. :) Getting back the 9V vs. AA, a 9v 150 mAh battery is approxibately equivalent to a 4.5v 300 mAh battery. 4 AAs gives you 4.2v at 1200-1500 mAh or more, which is 4x or more the capacity at the same price.

4.2V will be a bit iffy with a 5V hub, but it'll be easier to charge than having more than 4 batteries. Plus the more rechargeables you have in series, the more likely you are to have problems with cell imbalances. With a step-up regulator (not expensive if you're comfortable with homebrewing some elctronics - Maxim sells some great switching regulator ICs at http://www.maxim-ic.com/), you can power 9V hubs from 4 AAs.

Don't discharge the battery pack below an average of 1 volt/cell (4.0 volts total) - Any lower and you risk a cell reversal, which will kill the cell for sure and possibly damage other cells in the pack. (Not as much of an issue if each battery is individually removable - it matters more for packs of cells.)