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Build Your Own Electronic Key Card Lock

michael posted about 11 years ago | from the friday-night-build-your-own-series-continues dept.

Toys 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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Fuck teh niggers (-1)

applecup (683527) | about 11 years ago | (#7245952)

yes that is you you fucking linux faggots you can suck my cock you stoopid fucking morons fuck you idiots i will fukc your mom in her eye hole Firistus postus

Just a thought... (5, Interesting)

GMC-jimmy (243376) | about 11 years ago | (#7245960)

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.

Re:Just a thought... (0)

Anonymous Coward | about 11 years ago | (#7246156)

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.

because then there would be two stories: build your own goatse and build your own cowboy neal. I'm not sure which one I'd rather be associated with.

P.S. I did your mom last night.

Re:Just a thought... (0)

Anonymous Coward | about 11 years ago | (#7246160) would be cool

ATTN ADMINS!!! (-1, Offtopic)

Anonymous Coward | about 11 years ago | (#7246531)

look @ parent

Re:Just a thought... (1)

jimlintott (317783) | about 11 years ago | (#7246216)

How about a roll your own section?

Oops wrong website.

www.norm shit, fucking mouse.

Re:Just a thought... (2, Insightful)

Computer! (412422) | about 11 years ago | (#7246417)

Best first post ever.

This is a great idea.

Re:Just a thought... (2, Funny)

znode (647753) | about 11 years ago | (#7246499)

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!
(Read More... | 423 of 756 comments)

Roll your own Lightsaber recently published a guide on producing your own lightsaber with merely 2 hand-held fusion reactors and 2 focusing jewels.
(Read More... | 230 of 1123 comments)

Create your own Universe
Jehovah!God!Heaven has published a guide on making a home-made universe.
(Read More... | 445 of 1022 comments)

Re:Just a thought... (1)

BEHiker57W (253848) | about 11 years ago | (#7246704)

Create your own Universe Jehovah!God!Heaven has published a guide on making a home-made universe. (Read More... | 445 of 1022 comments)

This post was clever and nice and I did like it, but I have one pressing question.

Why is G_d still on bitnet? Can't he upgrade to a regular internet email system?

Re:Just a thought... (1, Insightful)

Anonymous Coward | about 11 years ago | (#7246811)

Isn't it a little ridiculous how many plans are out there on the net to build your own imitations of available commercial products? I envy, but also pity those who have the time and dedication to invest in such pirsuits.

I understand this may sound a little harsh, and many Slashdotters "root for the underdog," but I'm sure some of us here probably work in the consumer product industry and make our living designing/building/selling these things. The last thing we need is another one or one-hundred rogues to take away our business by giving away plans for cheap knock-offs.

Personally I wouldn't spend my time and money into these projects for a few reasons: they haven't been certified, they were designed by an amateur or amateurs (usually), and the cost of time, frustration, raw materials and tools required far exceed the price of just buying an off-the-shelf unit. And to a lesser extent, they are intended to undermine an existing company's business by discouraging the purchase of their product and instead building a cheap rip-off that is "almost" as good.

So why don't you..... (0)

Anonymous Coward | about 11 years ago | (#7246861)


(on your own)

Obvious Matrix Quote.. (3, Funny)

sinjayde (661825) | about 11 years ago | (#7245962)

But Mr. Anderson, what good is your custom made electronic lock when you can no longer find your card?

Re:Obvious Matrix Quote.. (-1, Offtopic)

Anonymous Coward | about 11 years ago | (#7246062)


Re:Obvious Matrix Quote.. (0, Offtopic)

netsharc (195805) | about 11 years ago | (#7246067)

"... when your computer is a melted piece of metal?" would be better. :p

Security by Semiobscurity (3, Insightful)

the_other_one (178565) | about 11 years ago | (#7245964)

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.

Re:Security by Semiobscurity (1)

LagDemon (521810) | about 11 years ago | (#7246017)

It's always harder to protect yourself from the people who acually can or want to hurt you, isn't it?

Re:Security by Semiobscurity (0)

Anonymous Coward | about 11 years ago | (#7246042)

People who do not understand electricity
Are a threat to your computer.

Re:Security by Semiobscurity (1)

JeffTL (667728) | about 11 years ago | (#7246123)

I agree. Better to use firewalls -- this is the work of BIOS or Open Firmware, and encrypting anything of extreme value.

USB Keycards? (2, Interesting)

theedge318 (622114) | about 11 years ago | (#7246724)

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 am totally suprised that I haven't seen one on SF. It makes me think I must be blind.

Re:Security by Semiobscurity (1)

Zibi (528341) | about 11 years ago | (#7246142)

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.

Re:Security by Semiobscurity (1)

twifkak (177173) | about 11 years ago | (#7246158)

Yeah, but you've got to admit it's pretty fucking cool.

Holy shit (-1, Flamebait)

Anonymous Coward | about 11 years ago | (#7245967)

That's GAY

Slashdot mirror (0, Troll)

LoneIguana (681297) | about 11 years ago | (#7245972)

This has already been slashdotted! I think slashdot should mirror sites before it posts the story to prevent killing these poor servers.

Re:Slashdot mirror (1)

1Oman (308666) | about 11 years ago | (#7245996)

Re:Slashdot mirror (1)

LoneIguana (681297) | about 11 years ago | (#7246115)

ok. I still think it should be a good idea. Most of these people are posting comments that are not to well thought out because they can't even read the full text of the story. One solution would be for slashdot to cache the page internelly, then after a story is released it could ping the server every minute or so to see if it has gone down. If it has, then the cached page could be brought up and people would still have access, if the server comes back up the cache would be removed. The caches would also be purged after 2 days, when the main wave has passed.

Re:Slashdot mirror (1)

Computer! (412422) | about 11 years ago | (#7246432)

Another great idea. Mod parent up, please.

Re:Slashdot mirror (0)

Anonymous Coward | about 11 years ago | (#7246748)

Most of these people are posting comments that are not to well thought out because they can't even read the full text of the story.
No, most of the people who post comments that are not well thought out do so because they don't want to read the full text of the story. Most people on Slashdot don't RTFA. They never have, and they never ever will.

Re:Slashdot mirror (0)

Anonymous Coward | about 11 years ago | (#7246506)

there is not enough profanity to express how bad that answer is.

As for commercial sites, they probably won't respond so slashdot away, but personal sites would gladly not be buried. The waiting six hours is crap since the articles are usually referencing something that's either been around for years or some cooler site has already referenced.

Or you could (3, Insightful)

structuredlynx (716671) | about 11 years ago | (#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 (2, Insightful)

RonnyJ (651856) | about 11 years ago | (#7246007)

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, there's nothing much you can do to stop them switching in on somehow, the only effective protection is to securely encrypt any sensitive data.

Re:Or you could (0)

Anonymous Coward | about 11 years ago | (#7246046)

Congrats. Your post had more words, less information, and many more errors in it than structuredlynx's.

Re:Or you could (1)

AlgUSF (238240) | about 11 years ago | (#7246048)

You are missing the point it isn't for real security. It is for the "look cool" (in a geek sense) factor!

Re:Or you could (3, Funny)

cybermace5 (446439) | about 11 years ago | (#7246146)

Not a problem if you weld the case shut.

Re:Or you could (1)

dracocat (554744) | about 11 years ago | (#7246199)

Or you could just take the whole damn PC.

Re:Or you could (1)

stienman (51024) | about 11 years ago | (#7246246)

Or fill it with concrete [] .


Re:Or you could (0)

Anonymous Coward | about 11 years ago | (#7246325)

"RMS and FSF are seeking power, not freedom."

Many people seek power. The real danger is that RMS and the FSF honestly believe that they are not.

Why the "funny" score ? (0)

Anonymous Coward | about 11 years ago | (#7246254)

Well, maybe welding IS an overkill :-) but there are some legitimate locks fo PC cases that can be drilled to the floor.

Re:Or you could (1)

Jeff DeMaagd (2015) | about 11 years ago | (#7246311)

Three of my computers include cable-lock tabs for padlocking. Add security screws and you'd at least frustrate people enough to bash your computer in.

Re:Or you could (0)

Anonymous Coward | about 11 years ago | (#7246501)

Until your shoddy wiring fails and you can't even turn it on...Of course that would improve slashdot.

The rest of us (who know how to solder) would run into trouble when it's time to upgrade.

Re:BIOS Passwords (1)

Artifakt (700173) | about 11 years ago | (#7246321)

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.

Re:Or you could (2, Funny)

jonadab (583620) | about 11 years ago | (#7246478)

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 software security that
prevent the already-running system from being compromised, should at least
make it abnormally difficult for an attacker to get at the data. Difficult
enough that the easiest way would be to obtain the private key (either by
surveillance or by rubber-hose cryptanalysis).

Alternately, you could just never leave the system unguarded. But then you
have to decide how "guarded" is guarded enough. Is it enough to leave a pair
of trained dogs in the room? A security guard with a handgun? A platoon of
goons with assault rifles? A couple of gryphons and a medium-sized dragon?

Re:Or you could (2, Insightful)

Professor Bluebird (529952) | about 11 years ago | (#7246495)

Also, if one can open the case, many boards have a jumper to reset the BIOS passwords.

I must be a sucker (2, Funny)

jaysones (138378) | about 11 years ago | (#7245982)

Here I am turning my computer on with the power button, like an idiot!

Re:I must be a sucker (0)

Anonymous Coward | about 11 years ago | (#7246210)

Really? Since I have no case and the motherboard just sits on my desk -- I use the nearest conductor handy (usually my keys) to short the power button jumper. Even easier than a button!

This is so 1995 (1)

_14k4 (5085) | about 11 years ago | (#7245984)

Popular Electronics had a very very similar article. Punched out phone cards.. all of that stuff.. only they had used old breadboard. Yum!

This is retarded, seriously guys (0, Troll)

Anonymous Coward | about 11 years ago | (#7246000)

Next on "Michael's Friday-night Slashdot Bag 'O Fun:" How to make a secure telephone with two tin cans and a piece of string.

This is so low tech it's not funny. Hey did you know you can take an LED, a resistor, and a battery and get a little shining light too? OMFGLOL!!1!

So why would you do this? (0, Insightful)

unterderbrucke (628741) | about 11 years ago | (#7246001)

Waste of time + money. Almost like women :D

Re:So why would you do this? (-1, Flamebait)

Anonymous Coward | about 11 years ago | (#7246018)

Hey now, don't discount the pussy, seriouly man. The only reason I'm on Slashdot on a Friday night is cause I'm killing time at work... working to make money to spend on hot bitches I'll be bumpin' uglies wit tomorrow. Oooh yeah.

Re:So why would you do this? (-1, Offtopic)

Anonymous Coward | about 11 years ago | (#7246816)

And you can't even have sex with this...

Punch Card (1)

Chucow (572393) | about 11 years ago | (#7246006)

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?"

Punchcards... again? (1)

downix (84795) | about 11 years ago | (#7246020)

excuse me for a moment, but WHAT?!?!?!?

Re:Punchcards... again? (1)

the_other_one (178565) | about 11 years ago | (#7246058)

Punch cards are actually significantly more advanced than this.

also in the article (0)

Anonymous Coward | about 11 years ago | (#7246032)

How to host your website with a 1200 baud modem.

1 button isn't enough (1)

Gyorg_Lavode (520114) | about 11 years ago | (#7246059)

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.

Re:1 button isn't enough (1)

LnxAddct (679316) | about 11 years ago | (#7246145)

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!!!!

Re:1 button isn't enough (1)

aardvarkjoe (156801) | about 11 years ago | (#7246337)

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.

Re:1 button isn't enough (1)

Sabalon (1684) | about 11 years ago | (#7246667)

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. :)

Re:1 button isn't enough (0)

Anonymous Coward | about 11 years ago | (#7246679)

May I suggest you add a third and label the buttons in the sequence: Ctrl, Alt, and Del?

Seems to have locked viewers out (1)

hhg (200613) | about 11 years ago | (#7246063)

How about turning the web-server back on? Bet a key-card could come in handy in that matter.

Obligatory Bill Hicks Quote (2, Funny)

edalytical (671270) | about 11 years ago | (#7246074)

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. []

Re:Obligatory Bill Hicks Quote (0)

Anonymous Coward | about 11 years ago | (#7246274)

that music sample was horrible. that guy is not even remoptely funny.. you can tell hes american. anyways the audience was also slow. i bet you modded that up with another account didnt you. so many people do that you know.

Re:Obligatory Bill Hicks Quote (1)

edalytical (671270) | about 11 years ago | (#7246497)

Bill Hicks is the best comedian ever! If you can't grasp the superior humor of a genius such as Bill Hicks I suggest you go watch Gallagher smash watermelons. "Yes folks it the amazing Sledge-O-Matic, it's not a slicer, it's not a dicer, but it can help get rid of pesky slashdot trolls."

Re:Obligatory Bill Hicks Quote (0)

Anonymous Coward | about 11 years ago | (#7246510)

I run a hotel, I've met them.
nice sincere salt of the earth people

I still washed my hand a few minutes later...

Though I know you are joking (1)

Sycraft-fu (314770) | about 11 years ago | (#7246521)

I actually HAVE met Gideons. They come to our university and hand out copies of the new testemant.

Turn On the Computer??? (1)

jetkust (596906) | about 11 years ago | (#7246078)

Yea but how do I get my computer to spit out cash like ATM machines do?

This is OLD! (0)

Anonymous Coward | about 11 years ago | (#7246079)

I remember an article in Rainbow which was a computer magazine that specialized in TRS-80 Color Computers (the Trash-80 Coco).

They described the project in great detail. It was a much better system, when you pulled the card out the computer would pause until it was reinserted.

Ahh, I remember my Coco - 1.5 MHz 6809E CPU, 64k ram, cassete tape, rom cartridges, and (WOW!) floppy disks. Some great games - Lancer, Cashman, Time Bandit. I think I was 9 at the time. I still have the daisy-wheel printer my parents bought for it. Still works great.

CoCo is tEh suXor!1!!1! (1)

Call Me Black Cloud (616282) | about 11 years ago | (#7246560)

Atari rulz!!!11!!

right on.

Personally... (3, Insightful)

LnxAddct (679316) | about 11 years ago | (#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.

Re:Personally... (1)

Jeff DeMaagd (2015) | about 11 years ago | (#7246516)

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.

Another idea (1)

sokk (691010) | about 11 years ago | (#7246103)

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 from using the computer when you don't want them too, and you have a little casemod :)

A simple scheme:

0 0 -0--0-\
#---1--1-/ 1 1 \
#-----------------O <- power on switch

Here the "code" is "1100". (#=pins on mainboard)

Re:Another idea (1)

Stephonovich (601356) | about 11 years ago | (#7246131)

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:-)

Re:Another idea (2, Funny)

Stephonovich (601356) | about 11 years ago | (#7246141)

BTW, by 4!==24, I mean 4! equals 24, not 4!=24. Although both of those are true...


Re:Another idea (1)

sokk (691010) | about 11 years ago | (#7246153)

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 :))

Re:Another idea (1)

Stephonovich (601356) | about 11 years ago | (#7246170)

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.


Re:Another idea (1)

Computer! (412422) | about 11 years ago | (#7246465)

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.

Re:Another idea (1)

jachim69 (125669) | about 11 years ago | (#7246225)

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.

Re:Another idea (1)

Dun Malg (230075) | about 11 years ago | (#7246243)

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?

Re:Another idea (0)

Anonymous Coward | about 11 years ago | (#7246837)

You are completely right. The original poster was completely wrong. If there was a prize for being wrong, he would win it. This guy eats, breathes, pisses, and shits wrong. He puts wrong sauce on his pancakes before eating them. When ordering at a restaurant he tries to order items that aren't on the menu, and he has the waitresses tell him he's wrong. If you look in the dictionary, there is a picture of him by "wrong". He got his middle name changed to wrong, and has the same plans for his first and last name.

Re:Another idea (0)

Anonymous Coward | about 11 years ago | (#7246162)

And how long did it take you to brute-force the switches in the game?


Re:Another idea (1)

Stephonovich (601356) | about 11 years ago | (#7246204)

As I said, while 4 switches might not take you long, with only 24 permutations, with 5 switches, there's 120, with 6, 720... And if you go further, as was said, and add 3-way switches into the mix, someone is going to have to really want your data to get past that.

Unless, of course, they just open the case, and bypass all your fancy tricks...


Re:Another idea (0)

Anonymous Coward | about 11 years ago | (#7246230)

What does factorial have to do with this?

The number is in binary, with four digits, hence 16 combinations, i.e. 2^4 .

Re:Another idea (1)

sokk (691010) | about 11 years ago | (#7246252)

You could use a padlock on your cabinet. A lot of cabinets have support for that :).

Re:Another idea (0)

Anonymous Coward | about 11 years ago | (#7246730)

HEY STUPID FUCK it's not permutations and combinations 4 switches with 2 potential positions each results in 2**4 combinations which is 16 you stupid sack of dumb fucking shit!!!!!!!!!! ass!

Re:Another idea (1)

Syrrh (700452) | about 11 years ago | (#7246522)

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 contact. Save yourself the tedium of even pushing a button, just turn the key on like a car ignition and set it back to the inactive position.

For the extra geek mile, find some little sound unit that can be wired into the completed circuit and trigger a car-revving sound effect.

I agree... (1)

Stephonovich (601356) | about 11 years ago | (#7246119)

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 Masterlock combination lock. The paper combination has been destroyed, and the only version other than the one in my head is PGP encrypted. From an average users' viewpoint, this is pretty tough to get into. Granted, with a hacksaw, you could break the chain in a few minutes. With a jigsaw with a metal blade, about 30 seconds. But I don't expect people to actually go attacking my box, so I don't have it covered with taser turrets or the like.

Pretty sucky analogy, I guess, but hey, it works...


Retro++ (1)

YouHaveSnail (202852) | about 11 years ago | (#7246121)

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!

Re:Retro++ (1)

jachim69 (125669) | about 11 years ago | (#7246234)

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.

It reminds me (1)

Joel Carr (693662) | about 11 years ago | (#7246133)

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... :)


Re:It reminds me (0)

Anonymous Coward | about 11 years ago | (#7246268)

I am going to do this. Not the case-mod, but the actual door-lock thingamajig. I just have to figure out how to get this OOPic to program right... then it'll be all sweet.

Why not use a floppy drive? (0)

Anonymous Coward | about 11 years ago | (#7246148)

If you could fit the nessesary components into a floppy drive, and then drill holes in a floppy disk, you could haave an almost invisible security feature.

help (-1, Offtopic)

Anonymous Coward | about 11 years ago | (#7246169)

i'm in #GNAA and penisbird is trying to dcc send me Gay_Niggers_from_Outer_Space_(1992).DCP.ShareReact or.mpg.

should I accept??????

Easy to break? (1)

Qweezle (681365) | about 11 years ago | (#7246194)

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. ;-)

Pointless and crappy (0)

mad flyer (589291) | about 11 years ago | (#7246205)

When you do something it should have some value...

Here it's obviously not for the safety, we're not at NORAD.

Maybe for the electronic know how ? well neither, i'm not a iron flux genius, but I think that everyone can obtain the same results with 1 quarter of the components (remember, in electronic, less is better, including for understanding how it works)

So maybe for the manual skills or cleanlyness of the job ? THAT's AWFULL, plastic modded with the iron flux, WOOD (!?) to place the leds where you can have done it cleanly with plastic parts from every "do it yourself" shops.

The whole article look like a big "look mum, i'm on the intarweb !".
Gyorg_Lavode reply about his second swith to power up trick is 10 times more useful (but for me it will be the reset switch that will be doubled... to many accident with this one)

do they work in florida? (1)

bryanthompson (627923) | about 11 years ago | (#7246241)

Do people in Florida need to be walked through how this works?

Old concept, nothing new (1)

mikeleemm (462460) | about 11 years ago | (#7246350)

I remember seeing this type of thing on several occasions years back on those electronics magazines and such..

DIY Lock (2, Interesting)

anubi (640541) | about 11 years ago | (#7246396)

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" cards out of the trash can, and went home and read them on my system, then programmed a few little AVR chips to recognize those specific cards. I keep one in my wallet to control the secure/access mode to my house alarm system and car. If it gets lost, its not obvious at all that the card has an alternate use. In the event I want some more cards, add or delete which cards work with the AVR, its not hard to put them back in the programmer and reflash their ROM with the new code list.

Actually, on mine, I never decoded the bar-code digits, I only kept track of whether it was a fat/narrow stripe and fat/narrow space by examining a counter interrupted on each rising and falling edge, and storing the counter state in an array. Upon scan completion, I examine the array and reduce it to 64 bits worth of fat/narrow of the first 32 stripes / spaces I encounter. There is a little start pattern at the beginning that helps a lot to align the data field so you are not shifted a bit or two off. To be on the side of possible error, I allow 8 bits to be bad before I declare the card invalid. This was from trial and error, as I could generate bad reads by not moving the card just right through the reader. I usually got at least one bit that wasn't right every time I scanned. I never did get it working absolutely perfectly. But then I did not really try that much on it after I had it working good enough. I think it was something to do with some focusing, and I could have used the analog side and some DSP to clean it up, I'm sure, but then I would have probably spent a good six months on it.

The only problem is I wish I had bought several dozen of those little optical slot readers when I had the chance. Anybody seen any out there ( dirt cheap ones, I mean - you know those surplus ditties they sell for a buck )? I am looking for some that just have the raw serial bar-code sensor out because I feed it right into the AVR.

My simple e-lock plans for your PC (1)

Bob Cat - NYMPHS (313647) | about 11 years ago | (#7246420)

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.

Even cooler... (1)

pr0ntab (632466) | about 11 years ago | (#7246642)

battery backed flash memory addressable via SMBus, which you program the "code" into, and the power switch only engages when the DIP pattern XOR values in NVRAM == all zero.

Punch cards (0)

Anonymous Coward | about 11 years ago | (#7246796)

This sounds an awful lot like using punch cards...are they making a technological comeback?

Must...resists...obvious...joke... (3, Funny)

IversenX (713302) | about 11 years ago | (#7246801)

In soviet russia, key card punches YOU!
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