Need Pro Help: Building an Audio Based Magnetic Card Reader

[4pyros]

So, if I understand you correctly, you want to swipe a credit card, decode it, and use the info later to shop in online shops?

Yes what do you really want to do with the card info?

 

[jordan rodgers]

You are not seeing the bare wires connected and labeled GR.

oh those ok, so there is no grounding required and both go to the L if the software can do that if I am interpreting this correctly.

Yes I have the software for it to work.

 

[jordan rodgers]

Yes what do you really want to do with the card info?

No I am not going to steal the card info for use later on. If I wanted to do that I would just purchase a device for that.

I am doing this to show the people at my comic book store how fun and educational electrical engineering is. So maybe they will get real jobs instead of living with there moms.

 

[dougy83]

oh those ok, so there is no grounding required and both go to the L if the software can do that if I am interpreting this correctly.

Not quite. The GR and L terminals connect to the two terminals of a magnetic read head. The R terminal should not connect to anything.

 

[4pyros]

No I am not going to steal the card info for use later on. If I wanted to do that I would just purchase a device for that.

I am doing this to show the people at my comic book store how fun and educational electrical engineering is. So maybe they will get real jobs instead of living with there moms.

Well thats good to here.
So if you have the software do you know if it needs both channels or just one?
Your laptop mic input is mono anyway, maybe the mono channel can be put on both of wav file tracks by audacity if needed.

 

[Reloadron]

Something you may want to consider and think about. If you look at a few financial institution cards like credit cards for example the magnetic strip positions are all the same. The magnetic strips are all about .223" down from the tops of the cards. The strips all occupy about the same height also and that should be about .330". Financial cards are all formatted the same to a standard. Within that .330" top to bottom there are 3 tracks of data, each track being .110". What this means is that when reading data on a two or three track card your read head must remain in or on the track you are reading. Not for example like using a wand to read a bar code where we can just swipe the wand over the code. If you look back at the German in the early link reading the card note how he used a straight edge and worked along that edge. Readers that read strips on credit cards actually have three read heads in a single package.

All this really means if we use a hacked read head (from for example a cassette player) is that we can only read a single track and in the case of a multi track strip we need to remain within that track. Everything depends on the type strip you are reading.

Ron

 

[4pyros]

Something you may want to consider and think about. If you look at a few financial institution cards like credit cards for example the magnetic strip positions are all the same. The magnetic strips are all about .223" down from the tops of the cards. The strips all occupy about the same height also and that should be about .330". Financial cards are all formatted the same to a standard. Within that .330" top to bottom there are 3 tracks of data, each track being .110". What this means is that when reading data on a two or three track card your read head must remain in or on the track you are reading. Not for example like using a wand to read a bar code where we can just swipe the wand over the code. If you look back at the German in the early link reading the card note how he used a straight edge and worked along that edge. Readers that read strips on credit cards actually have three read heads in a single package.

All this really means if we use a hacked read head (from for example a cassette player) is that we can only read a single track and in the case of a multi track strip we need to remain within that track. Everything depends on the type strip you are reading.

Ron

You could offset two or three heads to read more tracks.

 

[Reloadron]

You could offset two or three heads to read more tracks.

Sure. Long as you know what you are looking for and where it is. You could offset single heads or use a three head unit. Either way you are bound to mine some data. All my credit and financial cards look the same. Don't know why I have it in my wallet but I came across my wife's casino perks card in my wallet. Much wider strip and I would venture a guess likely a single track with her name and unique number? Traveling this weekend so I don't have access to my toys at home to play around. Anyway, yeah, two or three read heads offset would work fine.

Ron

 

[4pyros]

Much wider strip and I would venture a guess likely a single track with her name and unique number?

Do they not store the amount of money used or that pulled from a server with her number?

 

[4pyros]

Are some cards fixed and some writable?

 

[Reloadron]

Do they not store the amount of money used or that pulled from a server with her number?

Nope. This one is like a "Rewards" card. The only thing this one does is get discounts on things like food at the restaurants. There are other cards that do exactly as you mentioned though. They just opened a new Hard Rock casino a few miles from us. Man, I love the restaurants in that place. We are far from gamblers but do visit the place every now and then. This gets off topic but imagine thousands of slot machines all connected to servers. Every slot machine has a slot where a player can insert their cards. You do not have to insert a card to play but doing so earns you points as the machines eat your money.

The network knows exactly what you win or lose when your card is in a machine. When a machine pays and you decide to "Cash Out" it prints a magnetically coded strip and you drag that to a machine that spits out your money. Imagine the behind the scenes computing going on? The casinos amaze me. None of this begins to figure in all the video cameras and other security being recorded 24/7. While all of this is way off topic, the stuff is amazing.

Ron

 

[4pyros]

Talk about POS systems.

 

[Reloadron]

Talk about POS systems.

Huh? What's a POS system?

Ron

 

[Nigel Goodwin]

Huh? What's a POS system?

Ron

Usually 'Point Of Sale' - but 'Piece Of Sh*t' is sometimes used

 

[Reloadron]

Usually 'Point Of Sale' - but 'Piece Of Sh*t' is sometimes used

Hi Nigel, LMAO, I was thinking the latter which led to Huh?

Ron

 

[4pyros]

Usually 'Point Of Sale' - but 'Piece Of Sh*t' is sometimes used

Yep thats it. LOL

 

[Reloadron]

OMG, that was funny.

Ron

 

[zbyszek]

Why to make simple thing complicated? Use USB card reader like this: https://www.ebay.com/itm/USB-Credit...418?pt=LH_DefaultDomain_0&hash=item45fb96ebda . I have similar in my store, I can read card even in notepad.

Swiping card is like entering info from keyboard.

 

[4pyros]

Why to make simple thing complicated? Use USB card reader like this: https://www.ebay.com/itm/USB-Credit...418?pt=LH_DefaultDomain_0&hash=item45fb96ebda . I have similar in my store, I can read card even in notepad.

Swiping card is like entering info from keyboard.

Seems cheep enough, but what would you use for software?

 

[Reloadron]

Why to make simple thing complicated? Use USB card reader like this: https://www.ebay.com/itm/USB-Credit...418?pt=LH_DefaultDomain_0&hash=item45fb96ebda . I have similar in my store, I can read card even in notepad.

Swiping card is like entering info from keyboard.

Generally I would agree and just suggest a turn key solution. However, the original poster does mention:

No I am not going to steal the card info for use later on. If I wanted to do that I would just purchase a device for that.

I am doing this to show the people at my comic book store how fun and educational electrical engineering is. So maybe they will get real jobs instead of living with there moms.

Looking at it from an educational standpoint I would suggest making something out of hacked parts. Just something for simple demonstration purposes. There was a time when I had old cassette decks laying around but have since trashed so much stuff. Down here in Columbus, Ohio visiting my kids and grand kids and I would have sworn my sister had more junk in her basement but I can't find an old tape head. Going back home this morning so maybe I have something left in all my junk at home. The thread has me curious. Not curious enough to wind a sensor but curious.

Ron