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Build Your Own Electronic Key Card Lock 168

edBX writes " has a new guide up on how to make your own electronic lock using a key card. Built using a phototransistor, infrared-emitting diode and a few ICs, they are able to turn on their computer using a punched out phone card."
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Build Your Own Electronic Key Card Lock

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  • Just a thought... (Score:5, Interesting)

    by GMC-jimmy ( 243376 ) on Friday October 17, 2003 @09:46PM (#7245960) Homepage
    Why isn't there a "Build your own" section like "Ask Slashdot" or "Apache" ? Maybe even a "Slashdot How-To Guide" could turn out useful.
    • How about a roll your own section?

      Oops wrong website.

      www.norm shit, fucking mouse.
    • Best first post ever.

      This is a great idea.
    • Oh yay...

      Build your own Space Shuttle
      How to make your own space shuttle using only 230 thousand tons of liquid fuel, 23 tons of spacecraft-grade aluminum-titanium-magnesium-iron alloy, and five 1000-cubic-liter combusion chambers. Easy-to-follow blueprints here!
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      Roll your own Lightsaber recently published a guide on producing your own lightsaber with merely 2 hand-held fusion reactors and 2 focusing jewels.
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  • by sinjayde ( 661825 ) on Friday October 17, 2003 @09:46PM (#7245962)
    But Mr. Anderson, what good is your custom made electronic lock when you can no longer find your card?
  • by the_other_one ( 178565 ) * on Friday October 17, 2003 @09:46PM (#7245964) Homepage
    This device will keep the power switch safe
    from anybody that does not understand electricity.
    Anybody else can bypass the unit with a handy
    suitably reshapable piece of conductive material.
    Probably a piece of wire would do.
    Those whom the computer is protected against
    are probably not a threat.
    • It's always harder to protect yourself from the people who acually can or want to hurt you, isn't it?
    • I agree. Better to use firewalls -- this is the work of BIOS or Open Firmware, and encrypting anything of extreme value.
      • USB Keycards? (Score:3, Interesting)

        by theedge318 ( 622114 )
        Now this may not be more secure ... but I think it may have one up on the geek factor. Use the dandy/cheap little USB keychain devices to act as keycards to allow users to login/logout/freeze session. The cards we have with our Sun's are absolutely awesome, the only problem with it is the Solaris OS. Great for our sysadmin, but for GUI work, makes me wish for Windows (can't get Solaris-Gnome running).

        Anyways I think that a standard USB "keycard" would be an awesome Linux project (sorry GNU/Linux) and I
        • Re:USB Keycards? (Score:5, Informative)

          by dasunt ( 249686 ) on Saturday October 18, 2003 @02:42AM (#7247036)

          Linux Disc Encryption Howto []

          What it is: A method of encrypting a hard drive, and using a USB key-drive device and passphrase to decrypt the hard drive at boot.

          Why: To protect computers (especially laptops) from unauthorized access to the hard disk. Bios passwords, login passwords, and the above slashdot story do not prevent the hard drive from being removed from the machine and the data read in another machine.

          How it works: The laptop's drive is AES encrypted. At boot, the computer needs the key drive with the passkey and the matching passphrase to transparently decrypt the drive. It keeps a copy of the passkey and passphrase in memory, so the USB drive may be removed after booting. It only decrypts the files that it is using, so if power is lost at any moment, all data will remain protected.

          Why its cool: Its high quality encryption, OS tools, and protects your laptop's files from being accessed if its stolen. What more do you need?

          ( IMHO, way more deserving of a slashdot story then a simple electronic hack that can be bypassed by anyone with electronics knowledge. )

        • A cooler way would be to use one of Dallas Semiconductor's iButton devices as a key for your computer. An iButton is a little ROM chip in a sealed metal can that looks rather like a watch battery. You snap it into one of the holders, and it'll easily fit on your keyring (it's comfortably small too). Some iButtons even have secure facilities like SHA1 hash algorithms, onboard realtime clocks, and the like.

          I'm planning to make a device based on a PIC12F675 8-pin microcontroller to do just this. I'm even

      • Naw, this is talking about *local security*.

        At my house, we enforce local security with a 12 gauge shotgun.

    • I believe it is the concept that is being presented here. Yes, it may not protect your personal computer from anyone with at least a little knowledge, but the exact same thing could be carried over to a project where the person wouldn't be able to easily access the wires. Such as a case built into a cabinet in a store where to tamper with the circuit would involve dismantiling the device itself since the computer is hidden.
    • Yeah, but you've got to admit it's pretty fucking cool.
    • The biggest threat to my server's uptime is my girlfriend, mother or cleaner switching it off, and this would protect quite nicely against that. But to be really safe, it would have to be hard-wired into the wall, not plugged in with the standard IEC lead it is now.
      • Thing is, most people who are "un-technical" enough that they don't know that turning a computer off can typically be very creative in their ways of turning it off.

        If they don't see a power button on the front they simply jank the power cord. (And that's most likely worse, since the power button can be wired to give your computer a shutdown command.)

        And there's always the good ol' circuit breaker in case the previous plans fail.
    • Not without disassembling your PC.

      And if they are at your case with tools, you are fucked anyway.

      Personally, rather than flip a switch in the power supply, it would be more useful to rework the device to send a coded signal across the serial port. Run a daemon in the background that listens to the serial port, and then passes the appropriate information to PAM.

  • Or you could (Score:3, Insightful)

    by structuredlynx ( 716671 ) on Friday October 17, 2003 @09:48PM (#7245973)
    Why not just use a BIOS password. There are way more than 255 possible passowrds. If someone can figure out how to open the case and reset the bios, they can figure out how to connect 2 wires to bypass that device. A bios password is cheaper and more reliable.
    • Re:Or you could (Score:2, Insightful)

      by RonnyJ ( 651856 )
      A lot of common BIOSes have backdoor passwords hardcoded, which let an intruder gain access to the BIOS options without having to work out what the user set the password to. This unfortunately means it's not an effective way to safeguard your PC. Even if an intruder isn't able to use one of these backdoor passwords, he can always reset the BIOS by taking the battery backup out. In the end, no matter what precautions you take, with a standard x86-architecture PC, if an intruder has physical access to it, t
    • You are missing the point it isn't for real security. It is for the "look cool" (in a geek sense) factor!
    • by cybermace5 ( 446439 ) <> on Friday October 17, 2003 @10:24PM (#7246146) Homepage Journal
      Not a problem if you weld the case shut.
    • BIOS passwords work well on MBs built after about 1996, the vast majority these days. Some people still warn against them because of flaws that were fixed 5 to 8 years ago. Some businesses admittedly are still trying to get a little more life out of PCs that can't even run Win 95, and for them, BIOS passwords won't help (but then, what would?). One great advantage of BIOS passwords is that the earlier you limit access, the better, as a general security rule.
    • BIOS password is no good; all they've got to do is steal the computer, open
      the case by whatever means are necessary, and pop the drive into another

      If you need to secure against the case where someone gains physical access
      to your computer while it is unguarded, I can only think of one way to do it:
      encrypted filesystem with a large private key that must be typed in at boot
      time and is not stored on disk anywhere (never, for example, in swap space),
      just in RAM. This, combined with the usual forms of so
  • Here I am turning my computer on with the power button, like an idiot!
  • Popular Electronics had a very very similar article. Punched out phone cards.. all of that stuff.. only they had used old breadboard. Yum!
  • turn on their computer using a punched out phone card

    First thing I thought when I read this, "Interesting to be going back to those...for security?"

  • excuse me for a moment, but WHAT?!?!?!?
  • I actually put a second button in series with the normal power button because I was always kneeing my computers off. The second button is on the left side of the front bezel. You just have to push both buttons at the same time to turn the computer off/on.
    • Wow now that is security through obscurity, you give me step by step instructions on how to access your machine and dont tell me where it is!!!!
    • That's not a half bad idea. Although I wouldn't bother with the power button (the 4-second delay is generally enough), I currently have my reset button disconnected because I kept on hitting it. If I did the same thing, then I could have a quick reset again.
      • Took the front bezel off, removed the button part. Now I have to use a pen or something to poke in the hole on the bezel to hit the button.

        It was a bitch to hit initially, but my daughter had a knack. Now she's moved on to my wifes computer. :)
    • Now you just have to put them so far apart that one person can't reach both at the same time. They wire it to a key circuit and make a small board which requires both "buttons" to be pressed at the same time.

      After that you just have to find a room mate who'll put up with helping you turn the keys each time you want to turn you computer on.

      (Though your idea was pretty clever, I've had that problem sometimes with the reset switch. I have my current MB set so I have to press and hold the power button for 4 s
  • How about turning the web-server back on? Bet a key-card could come in handy in that matter.

    Who are the fuckin' Gideons? Ever meet one? No. Ever seen one? No. But there all over the fuckin' world puttin' Bibles in hotel rooms.

    Listen to it here. []
  • Yea but how do I get my computer to spit out cash like ATM machines do?
    • Empty your wallet into the CD-Rom tray.
    • A half-dozen stepper motors, a couple rollers, and a microcontroller to keep it all in sync. Rather like the paper feeder mechanism on any modern printer (which you can easily cannibalize for this, if you wish, although you will probably have to rebuild the logic board). Stack in some bills into a hidden compartment, and voila!

      Then you could always replace the light-gap cards with a real magstripe, and add a reader head and a couple op-amps. Tie it to the microcontroller, and away you go!

  • Personally... (Score:3, Insightful)

    by LnxAddct ( 679316 ) <> on Friday October 17, 2003 @10:14PM (#7246093)
    This isnt all that great of a security measure, however its good to see slashdot posting home project kind of things again. I dont know if its just me, but there haven't been many lately and I like to see what people are up to and building, its a lot better than all of this legal and corporate stuff thats been taking over my monitor. Not that I dont love my SCO fix, or yey some senator is in favor of open source, but hey even though our interests are getting lots of press now, we can't forget things like this. I don't know if anyone else agrees, but thats how I feel.
    • This isnt all that great of a security measure, however its good to see slashdot posting home project kind of things again.

      All that great? Be honest. The thing is a piece of CRAP! And it really isn't much of a tutorial of what is going on electrically either.

      That said, I agree, at least it is an honest project.
    • Yes but it has ZERO security to it. it would be easier to impliment a barcode that would at least be more difficult for someone to copy from a mere glance at it. or interface to a magnetic strip reader (not hard to do and just as cheap) that you can get for almost nothing from places like all electronics or the other surplus places.

      Or better yet, for the same money he spent, buy a ibutton reader and a couple of serial number buttons. you get massively higher security for the same really low cost plus.

  • I had an idea, and I almost realized it. It's very simple, but effective (not against someone who _really_ want to get inside your computer though).

    Think about Duke Nukem 3D. There were simple codelocks on some of the doors (on/off-switches). What about modding a row of switches (on/off) onto the front of your cabinet, and lead the cable for the almighty Power On Switch through them? So that they have to be aligned correctly for the computer to turn on. That way you have an effective way to keep people fro
    • Except for the fact that 4!==24, it's not a bad idea... Now, up that to 5, and there's 120 permutations. Now we're talking. (-:Stephonovich:-)
      • BTW, by 4!==24, I mean 4! equals 24, not 4!=24. Although both of those are true...


      • Yes, or you could use three-way switches to add some difficulty to it, without too many switches. -- Btw, I only added four to show the concept without showing off too much ascii-art :) (I've heard rumours about a lameness-filter :))
        • Three-way? You mean three position switches? Yes, 'twould work... except simple SPST switches are dirt cheap, and seeing a whole bank of 'em is dang impressive:-) It'd be cool to have to line them up in a certain order to get it to boot.


          • Very cool. Have them light up, too. Or with three-way switches, it would be like starting a helicopter.

            No Karma bonus, because that was the nerdiest thing I've ever written in my life.
      • Except for the fact that it's not a factorial.

        Any computer geek worth his salt would recognize this as a 4 bit binary value. So, 2^4==16 possible combinations, not 24.

      • Except for the fact that 4!==24, it's not a bad idea... Now, up that to 5, and there's 120 permutations.

        Aren't there only 16 combinations of 4 SPDT switches, and 32 of 5 of 'em?

    • Decent method, but if you're already in there adding pieces, why not just go for a regular keylock? Turning the lock to an open position connects a circuit between the power button and the PSU.

      Heck, on some cases you might as well just rip out the power button and bore it out to a circular hole for the lock. Rip a pair of spring-tabs out of the battery compartment from whatever you can find in the nearest dumpster. Glue one tab to the lock tongue, the and other to a point where it will rotate and make cont
      • All the parts you mentioned used to be sold at Radio Shack, and I even have a few on hand.

        They used to sell keylock switches for security systems. I suspect they still carry them. This would just be a straight replacement of the power switch with another switch. Simple enough. You could also pilfer these out of old machines that used to have a keyboard lock.

        As for the little sound device, the chip you are looking for is the ISD1000A (or, since it's now out of production, one of the newer versions of

  • While a dedicated person could easily get past this, there's still the cool factor. I mean, c'mon... slide a card in and it boots? How cool is that?

    I suppose one could lock your system case, but again, someone could break the locks. This, like everything, is a compromise in security/useability. For instance, I have a military surplus .50 ammo box that I store my personal stuff in. Letters, junk, Penguin Mints... It's locked up with ~ .75" (1.9cm for the rest of the world) hardened steel chain, and a

    • Why resort to Laser turrets. Just take an old lamp cord, and wrap the hot wire around an obscured part of the ammo box. Take the other end, and plug it into the wall.

      Conductive metal boxes are fun to secure. Ands nothing says "Don't Touch This" like 120/240VAC.

  • The card reader power switch has a certain amount of retro appeal. But to really do things right, wire one of those big red 1981 IBM PC power switches into your machine!
    • My previous main computer was in a case with a BRS (Big Red Switch). Too bad it was an AT power supply and ATX only uses a momentary contact switch.
      • You can turn the big red switch into a momentary contact switch a NAND gate, a resistor, and a cap.

        (Grr, Ascii art circuit diagram came out shitful) Connect the GND end of the BRS, and connects that to the "-power" wire. The +power wire goes into the A input of a NAND gate. The output of that NAND is wired to an R/C combination, which is in turn wired back to the B input of the same NAND.

        Yes, you are wiring the NAND to use it's output as one if its inputs.

        The output of the NAND should then be wired in

    • No better yet, one of the Big Red Buttons (BRB) like you see in the dinosaur pens. Of course, don't forget your Molly Guard.
  • A number of years ago in my teenage years I was going to put an electronic combination/key card lock on my bedroom door to keep people out. Only problem was my parents told me it was not on and threatened to remove the entire door!!

    Ahhh the memories... Still wish I'd done it though... :)

  • Couldn't this easily be bypassed...just break the thing? OR, WHAT IF it did break, then you cannot get into your computer? I am a bit confused as to exactly how this would keep the computer much safer than it already would be with a properly difficult password...and maybe a roll of duct tape. ;-)
  • Do people in Florida need to be walked through how this works?
  • I remember seeing this type of thing on several occasions years back on those electronics magazines and such..
  • DIY Lock (Score:2, Interesting)

    by anubi ( 640541 )
    I can't get to the article right now.. it seems to be inaccessable, but the article intro looked kinda cool.

    My trick was I found some old optical card scanners which would read the bar-codes printed onto credit-card sized plastic cards. Then I found the local gamery in the mall was using compatible cards, each coded with a different 24-digit number, being passed around to enable the various games as long as there was sufficient funds on account to the number of the card. Neat! I picked several "spent" c

  • Mount 16 SPST mini toggle switches on the case. Wire them in series to pass AC or 12v or whatever when they are in the ON position. But mount some of them upside-down. 64k possible combinations, and no case mod is cooler than a row of toggle switches that actually do something.

    Actually, keyswitches are a better idea. That might help you fight the urge to flip the toggles when the machine is running.

  • by IversenX ( 713302 ) on Saturday October 18, 2003 @01:17AM (#7246801) Homepage
    In soviet russia, key card punches YOU!
  • What use is a keycard lock without a giant stainless steel door protecting a diabolical evil invention clothed in dry ice and lit by a dull green glow?!
  • It's so rare today that you see someone building something out of small-scale logic ICs like shift registers and gates.
  • I mean, a perforated phone card is kind of sad.

    How about a remote control: as I walk into the room I zap my PC and it wakes up and says "Hi Heirony!"

    Or, proximity sensors tuned to my DNA. C'mon, just five minutes with a soldering iron, some capacitors, and a steady hand.

    But the ultimate, and I am seriously working towards this goal, is one's own personal PC assistant. "Good morning, Mr Heirony," says PC assistant 1 (I have a backup, but she's doing her nails this morning), "I saw you coming up the driv
  • by oPless ( 63249 )
    Most pointless project ever !

    Haven't these guys seen a keyswitch ?
  • I'm not sure why this article is supposed to be intersting and/or amusing. The "card reader" mechanism is lame, so it's not his engineering prowess that's interesting. His fabrication skills are abyssmal (did he cut the card slot in the plastic box with a soldering iron? cripes...), so it's not the elegance of the unti that's impressive. Is this supposed to be amusing because it's "kewl and 1337"? Please. OK, so the novelty of a computer that turns on with a card is worth something, but how much, really? I
  • As a side-project to this, how about something on how to modify up a little card-reader on the serial (or perhaps usb/parallel) port in order to access a machine. I mean, it's not a big deal to turn it on, that's fairly easy to bypass, but how about to login to the operating system.

    Personally, I'd find it much cooler to have somebody get to my personalized spiffy "Authorized Access Only" logo screen and have to put in a card (or click a special point onscreen and enter a username/password as backup).


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