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Wireless Networking Hardware

The Wireless Backpack Repeater 241

Posted by CmdrTaco from the i'm-to-sexy-for-my-backpack dept.
Andy Laurence writes "So, you've decided to do a webcast around the streets of Bristol, but your puny wireless NIC isn't up to it? You need the ultimate wireless repeater! Built from an old backpack, a lead acid battery, a Linksys wireless device, and a rather scary antenna, this wireless repeater will get you webcasting from over a mile away." You'd definitely burn extra calories hiking with that thing.
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The Wireless Backpack Repeater More

The Wireless Backpack Repeater

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  • Wondering... (Score:2, Interesting)

    by infofreako ( 194212 )
    I was wondering how we could do remotes with our new 80s radio station!

    Thanks.

    -nfo

  • Which Bristol? (Score:2, Interesting)

    by LostCluster ( 625375 ) *
    From surfing around the site, it seems to indicate that we're talking about Bristol, WA which is near Seattle... there's enough communities going by the name of "Bristol" in the USA this could get confusing.

  • As a bonus... (Score:5, Funny)

    by OhHellWithIt ( 756826 ) * on Thursday June 03, 2004 @02:55PM (#9328399) Journal
    ... you won't have to worry about being mugged for it. The police will be watching far too closely.

  • Solar? (Score:5, Interesting)

    by DrewBeavis ( 686624 ) on Thursday June 03, 2004 @02:55PM (#9328400)
    I wonder if here in Florida we could rig up a solar panel that makes enough power for this rig. That would make it lighter... but it might not work in places with less sun. Maybe a smaller battery and the solar panel?
    • Maybe a smaller battery and the solar panel?

      The battery is pretty small, probably a scooter battery. For the price, weight, and energy output, I don't think you can do much better than that.

      Yeah, it's England, solar power probably never crossed their mind...

    • IANwhoeverthehellwouldknowthisstuff but I'm guessing that the solar panel would probably have to be at least the size of an umbrella. Pretty awkward.
      • Put panels on an umbrella, then it gives you shade and power.

      • Re:Solar? (Score:3, Informative)

        by Jeff DeMaagd ( 2015 )
        My AP's AC->DC power supply is rated to 1A output at 12V . That is 12W. Given that sunlight is about 2kW/m^2 on a bright sunny day, and assuming a 10% conversion efficiency out of a panel (I think some are 15%), you might only need a panel that is about 25cm by 25cm. It is not all that large.

        Say you buy a 30cm x 30cm panel that generates current at 12V and buy small battery pack to store charge in the bright spots and to supplement power when a cloud passes, I think it could easily be done.

        I've been

  • Hey, what's that smell? (Score:5, Funny)

    by American AC in Paris ( 230456 ) * on Thursday June 03, 2004 @02:55PM (#9328401) Homepage
    You'd definitely burn extra calories hiking with that thing.

    ...especially if the lead-acid battery leaks.

    • A sealed battery [motorcyclecity.com] would definitely be a better option.
      • Which, judging by the pic, it is. Looks like a common sealed lead-acid Gel cell battery. They are common in both 6 and 12 volts and are found in exit signs, children's electric riding toys (aka powerwheels and the like), portable hand held spot lights, UPS's and many other things. I use them as a backup to power my headlamp on long caving trips (as an alternate to the NiMH pack that lasts 1/4 as long but weighs alot less). They dont leak, unless you manage to break the casing and squeeze the gel out of it (
    • You wouldn't burn much extra calories because that assembly is probably only 6 to 10 pounds, at most. Try humping an 80 pound rucksack over rough terrain, for a real burn...
      • Hmm, mine usually hovers between 50 and 60 pounds, or 23 to 27 kilos. However, a Marine Corps rucksack hovers around 85 pounds (38.5 kilos). This thing is nowhere close to either of those numbers.

  • More details on power? (Score:3, Interesting)

    by Quixote ( 154172 ) on Thursday June 03, 2004 @02:56PM (#9328420) Homepage Journal
    Some more details about the power connection (12v DC to the Linksys) would be nice. Anyone have any ideas? I'm not an EE, so please don't flame me crisp for asking...
    • The Linksys box probably gets 12VDC from its AC power adapter... So I doubt there's a whole lot in the way of electronics involved except for something to limit the current flow and thus not fry the thing.. And all you need for that is the right resistor.
      • Also, keep in mind that current won't necessarily fry a device.

        If you attempt to supply too high an amperage to a device, it will only take what it needs (at least that is what I've found with most consumer electronics... other than LEDs)

        However, too much voltage will always rip things apart if you've not the right fuse or protection. I'd add a fuse to this setup for the battery's sake; you would probably rather have a blown linksys than acid on your back.

        I was sitting here wondering why they didn't use

    • Re:More details on power? (Score:5, Informative)

      by tim_mathews ( 585933 ) <tmathews04&gmail,com> on Thursday June 03, 2004 @03:06PM (#9328523)
      Well, according to the manual for the router it takes 12VDC and the connector is + Tip, that is the positive wire goes to the inside part of the plug. So no special electronics, just wire from the battery to the router. The manual also says that the router draws 1.0amp, so I'd put a 1.5 - 2 amp fuse in line as well. The router probably has an internal fuse, but for an extra $0.50 why not?
    • Just a guess (since I don't have the Linksys device in question) but most of these are powered by a 9/12/whatever volt wallwart.
      It should be a simple matter to convert the 12V from the battery to whatever voltage is needed by the router with either a 3 terminal voltage regulator or even a zener diode.
      Or a DC-DC converter if you need more efficiency or higher than 12 volts.
    • Man, I'd love to try this when I'm riding round the world on a tiny (250cc) motorcycle. Can't power anything with the bike's magneto though. It'd be great to have a webcast run through a satellite phone. That way /.'ers could watch me die of thirst in the Outback while bitching about my connection and what version of linux I should've been using.
    • Actually V1.0 WRT54G's use a 5V 2A power supply. V1.1, 2.0 and WRT54GS models use 12V 1A.

      Unfortunately they use the same power connector so some unfortunate folks have watched a V1.0 go up in smoke when they mixed up the power supplies.

  • And then! (Score:3, Funny)

    by NeoThermic ( 732100 ) on Thursday June 03, 2004 @02:56PM (#9328424) Homepage Journal
    >>You need [...] a Linksys wireless device

    so now users can hack your rotuer as well with this article! [slashdot.org]
    Joy!

    NeoThermic

  • Not to mention (Score:5, Funny)

    by Prince Vegeta SSJ4 ( 718736 ) on Thursday June 03, 2004 @02:57PM (#9328436)
    You'd definitely burn extra calories hiking with that thing.

    what else would burn, when someone DoS's you, the router overloads the battery, and the acid leaks all over your back.

    • ahhh man, you beat me to the punch on that joke. I was going to say:

      Famous last words before entering the ER room for 3rd degree chemical burns....
      "Hey, why does my @$$ feel like it's on fire?"

      Ever get cold? Invite a hacker to hit you with a few "Pings of Death" and bask in the warmth of your router tx/rx all the requests.

  • burning (Score:3, Insightful)

    by musikit ( 716987 ) on Thursday June 03, 2004 @02:58PM (#9328444)
    "You'd definitely burn extra calories hiking with that thing."

    you'd definately be urning something. cancer/lightning stick on your back? i hope you were you lead hat as opposed to your tin foil to add more shielding

  • What about cancer? (Score:3, Interesting)

    by Anonymous Coward on Thursday June 03, 2004 @02:58PM (#9328445)
    People were concerned about holding cell phones close to their brains due to the risk of tumors. Isn't this thing going to fry your brain?
    • If you carry that contraption with you, rather than just getting a cable for your damn cell phone, your brain is already fried.

    • Re:What about cancer? (Score:5, Interesting)

      by RealErmine ( 621439 ) <commerce@nOspaM.wordhole.net> on Thursday June 03, 2004 @03:51PM (#9328929)
      Isn't this thing going to fry your brain?

      People need to look up the definition of non-ionizing radiation [osha.gov]. For comparison also look up ionizing radiation [osha.gov]. Exposure to non-ionizing radiaton does not have a cumulative effect over your lifetime. This (or your cell phone) is no more harmful to you than the local rock station broadcasting their signal.

      The worst thing that can happen from this kind of radiation is everyday, non-mutating burning (like your microwave), but the low power from the repeater won't do that.

      • Re:What about cancer? (Score:2, Insightful)

        by Anonymous Coward
        It's interesting that the link on non-ionizing radiation mentions that UV falls into that spectrum. UV can damage DNA and cause skin cancer, right? I'm confused then why non-ionizing radiation would be considered risk free? I'm sure you're probably right, I'm just interested in a more detailed explanation.
        • UV is ionizing. Ionizing means that you can remove electrons from atoms, and that happens already with frequencies in the optical range (Planck's E=hv is the formula you're interested in).

          Of course, radiation in the optical range, i.e. 'light' shouldn't be too dangerous for you :)

          It gets dangerous 'beyond blue'.
      • Of course, there is transcranial magnetic stimulation [unibe.ch].
      • The worst thing that can happen from this kind of radiation is everyday, non-mutating burning (like your microwave)
        Speak for yourself! I haven't accidentally microwaved myself for almost a whole month now.

  • Police Interest (Score:3, Insightful)

    by Cheeko ( 165493 ) on Thursday June 03, 2004 @02:59PM (#9328459) Homepage Journal
    I don't know about them, but I'd be worried about the interest of the authorities if I was walking around wearing this. You might get mistaken for a terrorist or some such. Its definately a cool idea, but it would be even cooler if it could be done in an inconspicuous manner, though that might be tough with the antenna.
    • I don't know about them, but I'd be worried about the interest of the authorities

      I don't know about you, but I'd be mored worried about being marked as a potential mugging victim.

      You see an antenna, I see a flag say "Look a geek!! Easy victim"

      ;-)
    • Hiding the thing might make it much easier to explain. I'd probably print up a little propaganda folder on the machine. Advertise on the back and expect questions.

      If you're just a repeater you dont actually have to do anything but stand there anyway. You probably dont even have to be quiet.

      LS

    • I don't know...at Purdue you will see students walking around now and again with funky backpacks with a funkier antenna sticking up out of the back. I haven't asked but I think it contains GPS equipment - don't know the class that is using them. That thing doesn't strike me as being that much different except that the guts are showing (the router).

  • never put a car battery on your back! (Score:5, Interesting)

    by Anonymous Coward on Thursday June 03, 2004 @02:59PM (#9328461)
    Just a tip, in case you were thinking of trying.
    I built something I called "loud backpack" once. It consisted of a 1/4" mic jack, 2 12" speakers, an amp, and a car battery.
    On a particularly warm day, my back started to itch, and it took a while before I realized that it was battery acid leaking through the padding, my shirt, and onto my back.
    Ran to the shower, falling once to scrape my knees, and immediately doused myself with water. Well, don't forget what they said about adding water to acid in high school chemistry class like I did... it burns!
    Anyways, amusing anecdote.. do not try at home!
    • You just ruined a terribly funny follow up story by telling people this. Shame on you.

    • Like my 7th & 8th grade algebra teacher used to say: "A little knowledge is dangerous."

      Both the author in Bristol & the poster above need to do a very minor amount of research & find a solution using a sealed battery (see my post above [slashdot.org]). Sure its easier to swipe one off the spare motorbike (which the pictured battery looks like - not a car battery), but do you really want an unsealed box of acid strapped to your body?

    • While your warning is certainly appreciated, wouldn't it be more helpful to just encourage folks to line their backpack with plastic? :)

      You can get rolls of plastic for cheap these days, and it wouldn't be all that hard to even double- or triple-line your battery compartment with it. It's my understanding that the garden variety clear plastic you can get at any home improvement store is impervious to sulfuric acid (and many others). I'm one of those folks who believes home experimenting and proper safety
      • Except acid eats through plastic. Try glass. Good luck.
        • Except acid eats through plastic.

          Not necessarily. Depends on the acid and the plastic. For sul(f/ph)uric (battery) acid, there's a number of suitable polymers. I believe polypropylene is usually used in lead-acid battery manufacture. (Car batteries made of glass don't travel well.) High-density polyethylene also resists acid quite well. PTFE (Teflon) doesn't blink on exposure to most acids.

          Heavy-duty rolls of plastic from the garden center, while not impervious to acid indefinitely, will definitel

    • Looks like the guy in the article is using a sealed lead-acid cell. These are no more likely to leak than a standard NiMH cell, and NiMH usually uses a potassium hydroxide electrolyte which is somewhat more dangerous to get on your skin.

  • I'm much more interested... (Score:4, Interesting)

    by AKAImBatman ( 238306 ) <akaimbatman AT gmail DOT com> on Thursday June 03, 2004 @03:01PM (#9328479) Homepage Journal
    ...in the possibilities of a dynamic WiFi network built out of electronic devices in close proximity. It would present a great number of engineering difficulties, but the payoff would be complete internet coverage anywhere in the world. ... Well, at least anywhere there's other people present to relay the packets.

    Hmm... I think there'd need to be a way of identifying open Internet points. Phones, laptops, etc. near these points would then need to broadcast their access. When a device receives a packet, it should know enough to accept or reject the route based on its current network uplinks. Bandwidth could present a problem, especially since a ton of small packet messages would be necessary to identify the current status of a given device.

    Anyone know of research that's currently being done in this area?

    • Anyone know of research that's currently being done in this area?

      No, but I've thought about designing a "Wireless Internet" as a research project, though I'm just a lowly undergrad. I'm sure it could be done; the biggest problem is signal strength/range.

      • the biggest problem is signal strength/range.

        Oddly enough, I see that as only a minor problem. In a typical city, people are close enough that Bluetooth connections would be sufficient. Here are a few of the problems I see:

        1. The various networking theories still apply. Thus the network will introduce more and more latency as it grows, and the bandwidth used to keep the network up to date will eventually cause problems. This is a very similar problem to the one of GNUTella, which eventually experienced
    • Isn't that exactly what Bluetooth [bluetooth.org] was supposed to bring us?
      • As I understand it, Bluetooth merely allows for devices to find one another. It does nothing to promote exchange between devices that are not directly connected via bluetooth.

        i.e. Getting my cell phone to communicate with my PDA will work, but sending an SMS message to someone two miles away won't.

        That's not to say that Bluetooth isn't a good option for creating such a network.

    • Yes, and I was interested since I had my first grasp of TCP/IP, packet switching and all that.

      I imagined every house with free space optical (FSO) devices on top of it+a router, long distance would be the last task for phone companies/ISPs. But sadly, it didn't happen.

      Maybe the telcos are trying to prevent that? Maybe people are too lazy and too stupid to grasp the whole idea? Remember, you'd have to convince many people to 'relay' packets before such a network gets usable. I don't really know, but IMHO i
      • Thanks for the info! :-)

        You probably would have to pay fees, but not because of the exchange from device to device. Rather, you'd probably have to pay for access to the Internet endpoints. Your packet would probably contain a device identifier that a provider would be able to use in tracking your usage and provide security for their endpoints. It would probably be difficult to stop someone from faking an ID, however...
        • > Thanks for the info! :-)
          No problem, It took me quite some time to figure them out even with google, because as another poster said, everything today is "mobile" and "p2p" and whatever. The right word here is "adhoc", I think... :)

          Hey, there is another idea and something I'd really like to implement if it is feasible, because it would be ONLY SOFTWARE that has to be implemented:

          - Provider-free Message-passing for PDAs and cellular phones -

          AFAIK, today's cellulars are equipped with much processing pow
    • Your talking about mesh networking. TCP/IP does not work well in large meshs. Addressing is an issue. Routing is an issue. If you can design or find a routing protocal that can deal with billions of routes in a secure manner it might work. Right now TCP/IP has big limits if you want to have stable packet ingress and egress you have to run BGP there is a limit of 65k BGP networks world wide.

      Having said that you can design small meshes that run fairly efficiently. The mesh has to have border points and
    • During the big Cedar fires last year, I had the crazy thought of some sort of portable/wireless device that would give you up to the minute news/road closures/accidents/ whatever about your local area.. possibly just text, but maybe graphics too. If the device could be made cheap enough, and enough people had them, they could establish a psuedo network, which doesn't rely on main lines (such as power/cable/phone) that could be destroyed or damaged in a disaster/attack.

      Maybe I'm just too much of a dreamer,

  • Script Children Rejoice! (Score:4, Funny)

    by turminalillness ( 753258 ) on Thursday June 03, 2004 @03:02PM (#9328481)
    I sure hope he has ports 80 & 443 forwarded. [slashdot.org]

  • That'll attract the women... (Score:4, Funny)

    by ardent ( 147548 ) on Thursday June 03, 2004 @03:02PM (#9328485)
    nuff said
  • I found that my Linksys WAP11 had major problems when I had a router stacked on top of it, I wonder if these guys have had any problems with heating?
  • and a rather scary antenna

    Anybody else think the antenna looked similar to the spooky wavy antenna that shows up in the Star Trek TOS episode: Shore Leave [cs.hut.fi] just before somebody's "wish" is about to be fulfilled?

    Maybe it's just me....sorry. I'd post a screenshot if I had my StarTrek TOS CDs with my right now. Maybe I'll post it in reply to this message later if anybody's interested. Sorry if it's just me.

  • Ghostbusters (Score:5, Funny)

    by sklib ( 26440 ) on Thursday June 03, 2004 @03:08PM (#9328532)
    The first thing that popped into my mind when i saw that backpack:

    DON'T CROSS THE STREAMS

  • Another step in building my gargoyle suit!!

  • Scary antenna?? That's no scary antenna.. (Score:3, Funny)

    by the_rajah ( 749499 ) * on Thursday June 03, 2004 @03:15PM (#9328599) Homepage
    They should see my car with the 3 ham radio antennas on it. Looks like an old Soviet "fishing" trawler. That's scary. Or a stack of single-band multi-element yagi beams for all the HF bands.

    "Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain
    • More like a porcupine. (I try to point them out to my wife whenever I see them in the hope she'll stop complaining about my single ATAS...)
  • Can't I just use a cooler full of pringles cans hooked up in parallel / serial (damnit Jim, I'm an artist, not an EE) to get some kinda sick signal range? Kinda like in the Simpsons, where Bart connects all the megaphones together?

  • Front page news? (Score:3, Insightful)

    by scosol ( 127202 ) on Thursday June 03, 2004 @03:28PM (#9328708) Homepage
    Some guy hooks an antenna to an access point, and uses a battery instead of an AC adapter?

    Come on guys...

  • Well, times are changing (Score:4, Funny)

    by digitalgimpus ( 468277 ) on Thursday June 03, 2004 @03:29PM (#9328717) Homepage
    Way back when, it used to be a sign that said "kick me".

    Now even that went digital.

  • Lead acid? (Score:2, Informative)

    by flying_monkies ( 749570 )
    Why not go Sealed Lead Acid [hepi.com] or, if you want to save some weight nicads/nimh? [battlepack.com]
  • What kind of alternative 12VDC batteries could be used instead of that potentially unsafe lead acid one?

    I think a laptop battery might do the trick, but where do you find the connectors?

    • Re:Alternative Batteries (Score:3, Informative)

      by jridley ( 9305 )
      It's not unsafe, it's a gel cell. They can run upside down or any other position for years and will not leak. The only potential problem is that if you short it out it'll get damn hot, but any decent battery will do that.
      Try it with Lithium Ion (from a safe distance) - they will explode when shorted. By comparison, lead-acid gel cells are tame.

  • Wimp (Score:4, Funny)

    by BenEnglishAtHome ( 449670 ) on Thursday June 03, 2004 @03:39PM (#9328813)
    Good God, what a wimpy battery. It looks like something from a motorcycle, and a small one at that.

    When I was in high school during the height of the CB craze, a kid I knew wired up a full-size truck battery to a CB, mounted it all on a gigantic aluminum backpack frame, and topped it off with a 12-foot whip antenna. The whole contraption probably weighed fifty pounds and brought him all the attention he presumably wanted as he wandered around baseball games wearing the thing, talking on the radio.

    The funniest thing? That skinny little kid was about 5 foot nothin' and weighed maybe 90 pounds. The whole rig looked like it was wearing him.

  • Fun with backpack batteries (Score:3, Funny)

    by switcha ( 551514 ) on Thursday June 03, 2004 @03:40PM (#9328818)
    I know a kid who had a side gig making a few bucks parading downtown in a huge inflatable sandwich handing out coupons for a big sandwich chain. There was a little fan and motor (to keep the 6 foot tall sandwich inflated) and a battery.

    One day, the battery started leaking and getting extremely hot. He stripped off the outfit just in time to avoid any heat or chemical burns, but about half the suit was reduced to a molten pile of plastic.

    If you ever need a laugh, check out a toasted 6 foot sub outfit (and no, this wasn't Quizno's *baddum-ching*)

  • If the outdoors is a problem for a temporary site why dont they just find a plug somewhere or put it on the roof of a running car. Are british cars not 12 volt in the cig lighter?

    If they could make it more weather resistant a Car could even be outfitted permanently.

    I still like the idea but think that if the range is a mile getting a car nearby is likely possible.

    ls
  • www.mjleonard.pwp.blueyonder.co.uk

    Does this make this a sixth level domain?

  • ...and his "one-man mobile satellite linkup"?

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