/sci/ - Science & Math

>>2105818
Go to priceline.com

bid 20 bucks for hotel room,

ask for 3 room keys

only return 1 room key

have 2 encodable cards to play with.

>>2105824
No no no no

Those are LoCo cards at 300 oersted, they will demagnetize too easily.

Will all HiCo readers take LoCo cards?

Time to somewhat hijack this thread.

I have a hotel card key that was given to my mom a couple years ago which now I keep.

How do I go about extracting and encoding information on it? What equipment will I need to accomplish that?

>>2105829
My hico reader does. And it is a cheap one. As for demagnatizing too easily, thats not necessarily a downside?


Otherwise 40 bucks gets you 100 cards online, but I assumed you wanted to get a card discreately.

>>2105856
card reader to extract

card writer to encode.

Let me elaborate a bit, I'm trying to copy HiCo type keycards that are designed for permanent use without reencoding. My setup will taking the track 1 dump and turning it into a WAV file which is played and amplified, then fed into an audio cassette head which writes to the card. Should this work?

>>2105867
recommend any particular card reader/writer?

>>2105870
I don't think the tape will hold the information well enough. running through a reader will damage it.

Also I have questions about getting readable information after running it as a .wav

>>2105872
any reader will work, don't own a writer myself so can't really make any recommendations.

>>2105901
Ahhh, but why? VHS at 650 oersteds is over twice a LoCo card! *Why* won't it work?

>>2105901
and the track is only encoded with 210 bits per inch, even at a speed of 100 inches per second you only need a WAV sampling frequency of twice the nyquist frequency, which in this case means a WAV encoded at atleast 42khz, but preferably somewhat higher.

>>2105921
and if we slow encoding to 2 inches per second, the nyquist frequency drops to 410hz, meaning our WAV can sample at anything over 820hz! (although far higher would give much better timing for the data)

>>2105910
The writing on the tape would work, but getting readable information seems, difficult?

Its like trying to use a c++ compiler on mython script.

or something. I could be wrong.

>>2105951
Isn't it just a matter of encoding the tape at a perfectly fixed speed of somewhat faster than 5 inches per second, the minimum speed on most readers?

Most readers max at like 100 inches per second, so you can theoretically have the data track take up only 1/20th of the card so long as it is timed properly and you swipe it very slowly.

Obviously that would be silly, but there is really no need to use the entire track so long as it is encoded at the same speed and swiped at a datarate between 1100 and 22000 bits per second, right?

>>2105969
To further elaborate...

Can't you...
-Encode half the stripe with all the data (420 bits per inch), and swipe it from 2.5 to 25 inches per second?
-Encode a quarter of the stripe (840 bits per inch), and swipe it from 1.25 to 12.5 inches per second?
-Etc

Again assuming the reader is designed for regular cards encoded at 210 bits per inches, and has a spec of 5 to 100 inches per second.

>>2105980
Sorry about the examples, the upper numbers should have been 50 and 25, not 25 and 12.5.

>>2105969
But how are you getting the correct information to play in the .wav so the head properly writes onto the tape, which you will need to manual move at the correct speed?

>>2105986
I already have a program that converts the ascii data dumped off the card back to the correct WAV file at well above F-nyquist.

As far as the card moving, don't I just need a servo to feed it at a consistent speed of somewhere between 5 and 100 inches per second during encoding (preferably somewhat above 5, but not too high) and just adjust for a shorter datastream in my swipe speed (eg if the data takes up half the card, don't swipe faster than 50 inches/sec).

Doesn't this work?

>>2105996
BTW the program I'm using is from the instructable about spoofing magnetic cards using an MP3 player (actually WAV in this case, but I suppose 320k mp3 would work well enough...), an amplifier and a solenoid on slotted iron (this last part is placed into the mag card reader and produces an EMF proportional to the amplifier output, just as the corresponding ferrite on a real HiCo card would)

>>2105996 I already have a program that converts the ascii data dumped off the card back to the correct WAV file at well above F-nyquist.

oh thats cool, then i don't see any problems, other than the reader dmamaging the tape. but should be good for a few swipes.

let me know how long it lasts,

>>2106012
So you don't see any problem with encoding less than the entire tape if I adjust my swipe speed?

And VHS is TWICE the coercivity of LoCo cards, how long do you think it would work?

>>2106019
ITs like the difference between sp and ep, the tape is very versatile in recording speed/space. there might be minor data loss, but shouldn't be anything noticable,

The lasting isn't going to be an issue of coercivity.

the tape isn't going to demagnify on you, the problem is the tape will physically get its data torn off of it by the reader. maybe 20 swipes, maybe 200 maybe 2000 not sure, just know it will have limited shelf life.

>>2106031
I'm going to be covering it with a 200 micron thick sheet of PP tape.

>>2106037
that would fix that problem then.

Im out of objections. test it out and let us know. sounds like you have everything covered.

>>2106059
Cool.

Will let you know once finals are over (three weeks for me)!

Bump.

>>2105991

buddy, thats exactly the fuck i was thinking