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Credit Card Transactions, readers — Parallax Forums

Credit Card Transactions, readers

xanatosxanatos Posts: 1,120
edited 2009-08-29 00:44 in Propeller 1
Has anyone made any projects that can facilitate credit card transactions using the propeller (or the stamp, but I doubt the stamp would have the power to do so)?· I have an application that would benefit from having the credit card payment system be embedded in the total device, rather than trying to interface to many different card payment boxes....· anyone do anything like this before?

Thanks for any info!!!

Dave

·

Comments

  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-08-27 22:43
    There is a Nuts & Volts column that explains how to do this with a Stamp, I don't have time to look for it now.....

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    I am microcontrolled.

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  • CounterRotatingPropsCounterRotatingProps Posts: 1,132
    edited 2009-08-27 23:56
    Dave, not having seen the N&V article microcontroller mentions, I think the card reader transmitters are very simple devices - and they tx/rv using old modem technology e.g. 1200 (or 2400?) baud. Considering that there's only a few chars going both directions, you don't need more than that. And, although I've not cracked open any of our POS stuff, it wouldn't surprize me if these didn't contain a humble Z-80 or some such. The real nut to crack will be the merchant session dialog on top of the simple comm protocol. (I just asked my merchant broker about is as he's been doing this stuff for 20+ years --- he just downloads the firmware each time he needs it.) Perhaps, it might be less work just to integrate a simple, pre-made POS system? There are tons out there...

    Wondering how in-depth the N&V article went on this?

    - H

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  • xanatosxanatos Posts: 1,120
    edited 2009-08-28 00:23
    Hi there,

    YES! I found the N&V article - THANK YOU MICROCONTROLLED! - looks very simple - even the BS1 could handle it I think! My challenge is that we need to take the range of credit cards, plus a whole bunch of non-standard cards, so after I determine card type (which is mind numbingly simple from the code example in the N&V article) - I would need to get that merchant session dialog thing going.... and I need to make it so that all these cards - bank cards as well as private issuers - can all be read by the same machine. Otherwise we'd have to integrate 5 or more pre-made POS systems.

    The N&V article covered a full reading of the data on teh card and displaying it - enough to obtain all data for a transaction, assuming you also added in a keypad for PIN entry, etc. Nothing about comm protocols, session dialogs, secure sockets layer, etc.... Looks like quite a challenge on that end of things.

    Thanks again for the info - any brainstorms or distant memories of useful info are, as always, incredibly appreciated!

    Dave

    PS., This will be my first project with the propeller! Got my first Prop Demo Board and wrote my first spin code today! WooHoo!
  • TinkersALotTinkersALot Posts: 535
    edited 2009-08-28 01:47
    xanatos,

    could you post the url to that article. Sounds like an interesting read.
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-08-28 02:34
    Thanks, I read the article a while ago when I was bored and just browsing the Parallax site, it caught my eye..........

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Computers are microcontrolled.

    Robots are microcontrolled.
    I am microcontrolled.

    But you·can·call me micro.

    If it's not Parallax then don't even bother.

    I have changed my avatar so that I will no longer be confused with others who use generic avatars (and I'm more of a Prop head then a BS2 nut, anyway)



  • hinvhinv Posts: 1,255
    edited 2009-08-28 02:40
    Where are the nuts and volts articles kept?
  • he1957he1957 Posts: 58
    edited 2009-08-28 03:57
    From the Parallax home page, Select the "Resources" tab, then the menu on the left.

    Here is a more direct link.

    http://www.parallax.com/tabid/272/Default.aspx
  • photomankcphotomankc Posts: 943
    edited 2009-08-28 13:36
    xanatos said...

    The N&V article covered a full reading of the data on teh card and displaying it - enough to obtain all data for a transaction, assuming you also added in a keypad for PIN entry, etc. Nothing about comm protocols, session dialogs, secure sockets layer, etc.... Looks like quite a challenge on that end of things.

    Not sure about the size of your installation but it might be worth using a small PC to handle the SSL and comm protocol to the banks if the design requirements would allow for it. Coding that with an OS library to call on for the networking would be rather simple where building the network from the bottom up on a microcontroller board would not be rather simple.
  • CounterRotatingPropsCounterRotatingProps Posts: 1,132
    edited 2009-08-28 22:55
    Actually, I'm pretty sure it doesn't use ssl - maybe some simplier encryption like CRC. These gadgets are dirt simple: a basic, stand-alone card swiper just has a phone jack w/modem and power. You have your merchant ID and the phone number it's supposed to call encoded into it by the merchant broker. You don't need multiple machines to do multiple card types - that's between your merchant broker and you. The broker will give you a phone number and a code to enter into the machine in 'function mode' --- it dials up the host and pulls in the firmware. So if your broker handles those card types, then he can set up your machine. I'm %99 certain you can't just go directly to the horses mouth (VISA, MS, etc) - you have to go through a broker/middleman.

    This is were you may well get stuck, because - for obvious security reasons - they won't just give you the required session access protocols. (Sure many of us here could hack such a stream - but that's because we're good and well beyond average [noparse]:)[/noparse]) --- the card company security guys aren't considering people like this.)

    So even if you build it, you won't have anything to run on it. And by the time you have hacked someone elses machine (which is probably highly illegal ! even with their permission!) you've still got to get that merchant firmware download, which in turn contains a valid merchant ID and the phone codes to get in the door.... in other words, you have to have a contract with a broker who has contracts with the banks/card co's.

    - H

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  • TinkersALotTinkersALot Posts: 535
    edited 2009-08-29 00:44
    the hard part will be to get your device certified to communicate with the processor's switch....Those guys have this game down....try to licens DUKPT for example
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