[SOLVED] - Redeeming Unique download Codes - is there a Mod?

Hi All,
I use my store to sell Records (vinyl) which I have manufactured for me and the Bands I work with. Although I sell a physical item, which customers buy and pay postage for, I insert a small card with each record which contains a URL to a website where they can enter a unique code (also printed on the same card). This allows a 1 time Download of the record in an MP3 format.
Until now the Vinyl Pressing plant i use was offering this service free of charge so i used their MP3 hosting. Now they are charging for it so I want to do it myself.
I have been able to set up my site to allow a downloadable product when the customer buys the item from me, but I also send my records to UK stores who sell them from their shops/point of Sale.
I therefore need an independent feature. Where I can Place a downloadable product, which can be downloaded providing you enter a valid code. The code needs to be Unique (example, i want to load 1 MP3 zip file and create 300 unique codes). I want to ensure that each code only works once, and only works for this product (not the MP3 Zip of a different record i made and they didn't buy).
Ideally i would like them to resister or at least enter an email address (got the get them for marketing!)

Anyone know of such an extension? I have searched, download codes, redemption etc.
Maybe coupons that are restricted to just 1 product?

Your request is very specific to your own situation, I do not think there will be such an opencart extension. Opencart is a e-commerce system and the function you need is kinda like a one should probably exist in a CMS system, downloading free music files with a code that can only be used once.

The desired extension should do this for you:
(1)Add an option called "one time downloadable product", which could be checked and unchecked, to the product edit page in the admin end.

(2)Add a new page in the admin page, which bulk-generates uqniue codes for individual or multiple one-time downloadable products.

(3)The codes generated are sequential. By saying sequential, I mean codes will be generated in this way: the first code ever generated is like "A00000000000001", the second one "A00000000000002", the third one ever generated is "A00000000000003" etc. Yes, there will be no duplicated codes generated, even if a code is generated then deleted from the database, no identical codes will generated.
How do we do this? Everytime you generate some codes, the extension inserts or update a record of the last generated code and the product ID the code is bound to into the database. Next time you generate codes, the extension will check this record and start from where it stoped last time and start genreating the next sequential codes.

(4)On the front end of your site, if a product is a one-time-downloadable one, the cart button is hidden from the product page, search page and category page. Instead a box for entering the code appears on the product page. Once a correct code, which is bound to a unique product and has never been used, is entered, a customer is able to download a product.

(5)Once a code is used by a customer, the code is deleted from the database so that your database won't become huge with so many old used codes persisting. A bulky database might cause your site to load slowly.

I can develop this extension for you. If you are interested, pm me for a reasonable quote.

But before pming me for a customized extension, try googling relevant keywords in this way:
xxxxxxxxxx site:http://www.opencart.com/index.php?route ... /extension

I am still happy if you can find an off-the-self extension that suits your need

Thank you for the reply uNeverNo,
Sorry to take so long to answer - ended up in hospital a couple of days after posting!
I' all OK, but i had completely forgotten i had asked this question. Just got back to the issue and remembered. So sorry since you answered so fully.
I managed to set this up myself this week using a wordpress addin someone created, so i have set it up slightly separately to Opencart.

Thanks,
Paul