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The battary powered switch!


Sparda
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Does any one know the theory behind how to do this. To me it seems simple, just get a battary (or set of battaries) that sumount to the voltage that the power supplie that comes wiht the switch supplies, and it should work, is it realy that simple, or am i missing some thing?

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If the total voltage (to increase the volltage connect the battaries in SERIES, not parralel) is 6V, then maybe, if you don't need/want the switch then it's worth a try, and if it works, grate, we can make battaty powered switch.

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Wikipedia knows all! (but some how less then Google).

If you can desipher this:

"Cylindrical plugs generally have an insulated tip constructed to accept insertion of a pin (but note also the internal pin in the larger size EIAJ plugs). The outer body of the plug is one contact, most often but not always the negative side of the supply. A pin mounted in the socket makes contact with a second internal contact. The outer plug contact is often called the sleeve, and the inner the tip, although the tip itself is actually non-conductive."

Then you can wire it up proerply, apparently the outer sleave is most commonly the negative connector, with the middle one been the posative. The artical about this is here.

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1.jpg

The basic setup, one compaq armada 3500 running ubuntu 5.10, and one Dell X300 running Slax/Back|Track. The PCB is part of a LanPro 10base-T ethernet hub powered by 4 AA batterys.

4.jpg

5.jpg

I had no solder so i used sticky tape, works fine unless you move it.

2.jpg

Ubuntu doing a continous ping...

3.jpg

Ethereal on Back|Track picking up the pings...

Room for improvement

Solder!!

Needs a battery holder and a toggle switch.

Plus, the case itself is big enough to hold the batterys so in V2 we should have a self contained battery powered hub...

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dude! that's just my kind of hack!

anyone trying this or similar hacks might want to know that those little cylindrical power connecters that wall warts have usually have the centre pin (the hole, as opposed to the metal on the outside) usually carrying the + rail... this is not always the case and when testing, try not to leave the power (in this case your batteries) connected for longer than is required to find out if it does/doesn't work... if it's the wrong way round, the hacked thing won't turn on and if it does then your polarity is correct!

It is much easier to have a few of those power jacks spare, like perhaps a few cut from the ends of wall warts and then when you come to connect the batteries and apply the power, you don't need to rip the case off of whatever you're hacking to be battery powered... just trim and skin the 2 wires and connect your battery/batteries and plug it in!

Often, there is a wire that has a white stripe down it - this is (usually) the + rail. With the right batteries and the right power jack, anything that has a wall wart or power brick can be powered by batteries... That is, unless the power brick outputs AC current, though that's not very often - your power brick/wall wart will usually say on it which one - if the output figures have a '~' next to them. you probably can battery power it without a seperate circuit.

Just keep an eye on the current (Amps = A/Milliamps = mA) and you'll be fine!

happy mobile hacking!

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Well, you might be able to work it out. If the switch uses 600mA of of energy per hour, then it will last at least an houre, you can buy 650mA battarys cheaply and widly, you can get more long lasting batterys, but an hour would hopfully be long enough for most man in the middle atacks.

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On second thought, if all the battarys have 650mA of power in them, wouldn't that means that you multiply it by 4? so the amount of power they could posabily supplie in an houre is 2600, so devide 2600 by 600 you get 4.3 hours. I'm not exacly certin, it's either going to die after a hour or 4 .3 hours, leave it running and tell me which ^^, it would also be nice if some one who knew exacly what they where doing when it comes to electrics said how it works.

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Didn't gut the power supply since I still use this switch in rare circumstances. Plus, I want it self contained.

My plan is to get a soldering iron and work on this some more. To broke to buy more batterys right now, so once i have it set up a little nicer I'll do some more extensive testing and work out how long it lasts. And yes, if anyone knows anything about electronics, please enlighten us. I know the basics... but thats about it. If i can get some gum-stick batterys (what they use in sony MD players) i should be able to fit this entirely in the case. The AA's are slightly to fat once the PCB is back in its box.

The adaptor says 6v, but a multimeter shows its putting out closer to 9v.

Also, goes to show what you can do with half an hour, some tape, cat5 & foil and old electronics kit.

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I'v done a spot of reading, and descused this with a friend, a set of four 1.5V 650mA battaries will give a 600mA switch 1.08 hours of life, the number of battarys does NOT increase there life span. To increase the amount of time the switch has to live you would need to add anotehr set of four in parralel with the the first set.

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Basically the value of this is that you have a working device when you're unable to get near a power source. Given the limited time the batteries can provide power, how difficult would it be to put together a setup that will run off of mains power through an adapter when it's available, and switch to the batteries when it's not? In other words, an UPS for your switch/hub/device?

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The idea is that you are going to use it covertly, how covert is plugging in a switch and having a flashing thing sat next to you? Not very, this way you can easily conceal the switch, also, in public places if you plug any thing in that they havn't had tested they can get in trouble with the saft person and will probably kick you out for doing so.

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The UPS idea is cool, don't know enough to build the circuit to switch between batterys and mains though. It would be nice to work a solar cell into it somehow, and rechargeable batterys. Then you have a ethernet repeater that could work any place without a power point.

The covert idea is nice also, just hollow out an old textbook and use that as a case. Add a gumstick linux computer into the mix, and possibly wireless to. That way you could leave the book somewhere, and have a remote control wireless hacking device. But thats waaaaay beyond me.

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Okay, but I'm still curious how hard it would be to alter this setup to a small UPS for doing work in areas where there simply isn't a poweroutlet available, or as a UPS in case the power goes and that particular device should really stay on. A real UPS tends to set you back quite a few dollars.

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Well, you would have one of thoughs trigger switches, where when power isn't flowing though one cercuirt it chooses cercit one (The battary) but when it is it chooses circet two (the mains source), it's that simple... ok, it's not exacly simple, but thats the idea.

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